I have a used 3 way fridge that I am going to install in my Burro to replace the ice box. I know it works because I pulled it from my old popup camper. I am ready to build the platform and connect AC and DC connections. But I am not ready to install the propane (I need to replace all propane lines first) nor am I ready to cut the two needed outside vents.
Any thoughts on running the fridge on either AC or DC without vents? Aren't the vents only needed for propane?
Looking for some guidance before I do something I regret.
Thanks
Mike
Full Version: 3 way fridge question
FiberglassRV > All About Our Unique Little Molded Fiberglass Trailers > Problem Solving -- Owners Helping Owners
QUOTE (MikeCM @ Oct 15 2009, 03:12 AM) 
I have a used 3 way fridge that I am going to install in my Burro to replace the ice box. I know it works because I pulled it from my old popup camper. I am ready to build the platform and connect AC and DC connections. But I am not ready to install the propane (I need to replace all propane lines first) nor am I ready to cut the two needed outside vents.
Any thoughts on running the fridge on either AC or DC without vents? Aren't the vents only needed for propane?
Looking for some guidance before I do something I regret.
Thanks
Mike
Any thoughts on running the fridge on either AC or DC without vents? Aren't the vents only needed for propane?
Looking for some guidance before I do something I regret.
Thanks
Mike
If you are not going to use propane then maybe you should consider simply buying a 110V dorm fridge or a coleman 12V.
Mike,
I repair these, my answer is watered down a little off the technical side.
These are absorption refrigerators, they absorb energy from inside compartments (where the food is) and move it to outside (to where the fins are)...these systems do not make cold...they move heat energy, the heated air coming off the back of the equipment fins/coils is picking up heat/energy being moved out of that inside space to the outside space " the outside fins facilitate this" if they do not breath they will fail to operate.
This is true of any mechanical device that transfers heat energy from point a to point b.
Since in R.V.s we do not use outside fans (generally by design) to exhaust heat away (like under your home refrigerator or your home a/c) must rely on the subtle air currents of convection..."this is cooler air entering thru the bottom part of the appliance at the rear part thru the vented door outside is drawn up across the coils/fins picking up heat. The heated air really being lighter than the cooler incoming air at the bottom will gently exhaust thru the top vent taking the nasty heat energy away outside.
The answer to the question is under no circumstances run this with out venting, you are correct, the gas combustion products also exit thru the venting system BUT that is only one purpose for the vents as outlined above.
This is a great question, your thoughtful to investigate your issues prior to design changes, shows you thinking ahead.
Happy Camping, Safe Trails.
Harry
I repair these, my answer is watered down a little off the technical side.
These are absorption refrigerators, they absorb energy from inside compartments (where the food is) and move it to outside (to where the fins are)...these systems do not make cold...they move heat energy, the heated air coming off the back of the equipment fins/coils is picking up heat/energy being moved out of that inside space to the outside space " the outside fins facilitate this" if they do not breath they will fail to operate.
This is true of any mechanical device that transfers heat energy from point a to point b.
Since in R.V.s we do not use outside fans (generally by design) to exhaust heat away (like under your home refrigerator or your home a/c) must rely on the subtle air currents of convection..."this is cooler air entering thru the bottom part of the appliance at the rear part thru the vented door outside is drawn up across the coils/fins picking up heat. The heated air really being lighter than the cooler incoming air at the bottom will gently exhaust thru the top vent taking the nasty heat energy away outside.
The answer to the question is under no circumstances run this with out venting, you are correct, the gas combustion products also exit thru the venting system BUT that is only one purpose for the vents as outlined above.
This is a great question, your thoughtful to investigate your issues prior to design changes, shows you thinking ahead.
Happy Camping, Safe Trails.
Harry
QUOTE (Harry Young @ Oct 14 2009, 11:50 PM)
The answer to the question is under no circumstances run this with out venting, you are correct, the gas combustion products also exit thru the venting system BUT that is only one purpose for the vents as outlined above.
Good question Mike, and great response Harry.
My fridge is a rare exception to what Harry says about the combustion gases - only because it has it's own direct intake/exhaust vent separate from the cooling vents.
I modified the cooling vents and the air flow over the rear fins and the fridge efficiency noticably improved. I still have not added the 12V computer fans. Details can be seen here:
http://www.fiberglassrv.com/board/index.php?showtopic=30778
Proper venting makes a huge difference.
Roy and Harry thanks. I had a feeling that I should wait till I was ready to do the whole job, but did not know why. I wont need it for the next planned trip so I can wait till I can do it right.
Floyd I will be using the propane eventually, just not ready to. Over the winter I plan to have all of the propane lines replaced at a local shop, right now they are all original and I can see leaks in the hose. Not willing to gamble with a leak.
As always ask a question here and get an answer and understand why too.
Thanks Mike
Floyd I will be using the propane eventually, just not ready to. Over the winter I plan to have all of the propane lines replaced at a local shop, right now they are all original and I can see leaks in the hose. Not willing to gamble with a leak.
As always ask a question here and get an answer and understand why too.
Thanks Mike
Harry, nice to have a "go to guy" for the ammonia (?) coolers! I also have one sitting on the shelf and man it is scary to think about putting in. Just being afraid I guess. 
I agree with you Pat --- it sure is nice that Harry chips in with his vast store of knowledge. Also, it's one thing to have the knowledge, and quite another to be able to pass it on effectively in writing 
Isn't it true about the ammonia/propane "scary" angle? I know just what you mean, Pat, as I have had that feeling myself. And it's good to be careful. But what's funny is how blase we all are about electricity. I mean, Hello! 120 VOLTS! I guess it's just that people use it all the time and so they don't think about it as much. Also, wires are so "clean" and they don't rust and whatnot.
Raya
Harry, that was a great explaination.
Harry, another question for you:
I did a lot of research before I installed my 1.9cuin Dometic 2190 3-way into my Scamp.
I found this info about venting online. In it, there are instructions to keep a baffle between the lower control area from the upper cooling fins. So I did. I also installed two computer fans into the upper venting area (one pulls and one pushes) to help create circulation.
Is this baffle necessary. Or worse, causing a potential problem? I just rechecked the "manual" from Dometic and there's no mention of the need for any baffles.
Can you share any thoughts? Thanks.
RJ
I did a lot of research before I installed my 1.9cuin Dometic 2190 3-way into my Scamp.
I found this info about venting online. In it, there are instructions to keep a baffle between the lower control area from the upper cooling fins. So I did. I also installed two computer fans into the upper venting area (one pulls and one pushes) to help create circulation.
Is this baffle necessary. Or worse, causing a potential problem? I just rechecked the "manual" from Dometic and there's no mention of the need for any baffles.
Can you share any thoughts? Thanks.
RJ
Robert,
I'll be interested to hear Harry's take on this.
When you installed your baffle(s), did you leave the 1/4" space they specified?
The way I understand it it's not so much the baffling itself that is important -- or that the baffle "separate" the control area from the cooling fins -- but more the fact that you are trying to create a chimney effect (sucking air up and out), and if your open space behind the fridge is too wide, you won't get that effect. Like the difference between your large living room (basically still air) and your (relatively) small fireplace chimney (air sucking up).
If I understand it correctly, I also see that they mentioned that one could also make the whole "chimney" area behind the refrigerator 1/4", by filling in between the baffles, if it were safely possible.
Raya
PS: Note that my info is only from a combination of reading that document you linked to, and having experience with wood stoves. With wood stoves, people would often install an 8" diameter chimney on a small stove, thinking a larger chimney would work better; when in fact, a 5" chimney would provide more draft (and the heat would make less creosote form; not that that means anything for a refrigerator).
I'll be interested to hear Harry's take on this.
When you installed your baffle(s), did you leave the 1/4" space they specified?
The way I understand it it's not so much the baffling itself that is important -- or that the baffle "separate" the control area from the cooling fins -- but more the fact that you are trying to create a chimney effect (sucking air up and out), and if your open space behind the fridge is too wide, you won't get that effect. Like the difference between your large living room (basically still air) and your (relatively) small fireplace chimney (air sucking up).
If I understand it correctly, I also see that they mentioned that one could also make the whole "chimney" area behind the refrigerator 1/4", by filling in between the baffles, if it were safely possible.
Raya
PS: Note that my info is only from a combination of reading that document you linked to, and having experience with wood stoves. With wood stoves, people would often install an 8" diameter chimney on a small stove, thinking a larger chimney would work better; when in fact, a 5" chimney would provide more draft (and the heat would make less creosote form; not that that means anything for a refrigerator).
Roy,
What you have could be the French built and designed refrigeration unit, Dometic contracted these in the early years (late 60s thru 70s) when the Canadian Gas Association was trying to grapple with standard design practice for Canadian R.Vs appliance. standards in their country, latter they ceased being built in Europe because they were deemed a shipping hazard, (bogus claim to get it built here) the parts were sent un-assembled to the U.S.A so that final assembly was done here when the gases were installed....The furnaces of this era were somewhat different too being made in the U.S.A. to Canadian rules...Take alot of pics and archive them, to my knowledge I have seen only one other system like yours...Therm-ex built a French cat heater import which used a strange (to me) series of pilot safety's for Canada also specified for the Dominion of Canada.
People do not realize the journey technology took to get here today or the cowboy mentality of the early years.
Harry
What you have could be the French built and designed refrigeration unit, Dometic contracted these in the early years (late 60s thru 70s) when the Canadian Gas Association was trying to grapple with standard design practice for Canadian R.Vs appliance. standards in their country, latter they ceased being built in Europe because they were deemed a shipping hazard, (bogus claim to get it built here) the parts were sent un-assembled to the U.S.A so that final assembly was done here when the gases were installed....The furnaces of this era were somewhat different too being made in the U.S.A. to Canadian rules...Take alot of pics and archive them, to my knowledge I have seen only one other system like yours...Therm-ex built a French cat heater import which used a strange (to me) series of pilot safety's for Canada also specified for the Dominion of Canada.
People do not realize the journey technology took to get here today or the cowboy mentality of the early years.
Harry
QUOTE (Roy in TO @ Oct 14 2009, 09:51 PM)
Good question Mike, and great response Harry.
My fridge is a rare exception to what Harry says about the combustion gases - only because it has it's own direct intake/exhaust vent separate from the cooling vents.
I modified the cooling vents and the air flow over the rear fins and the fridge efficiency noticably improved. I still have not added the 12V computer fans. Details can be seen here:
http://www.fiberglassrv.com/board/index.php?showtopic=30778
Proper venting makes a huge difference.
My fridge is a rare exception to what Harry says about the combustion gases - only because it has it's own direct intake/exhaust vent separate from the cooling vents.
I modified the cooling vents and the air flow over the rear fins and the fridge efficiency noticably improved. I still have not added the 12V computer fans. Details can be seen here:
http://www.fiberglassrv.com/board/index.php?showtopic=30778
Proper venting makes a huge difference.
Harry,
Did you have a chance to see and read my questions about my Dometic, posted here on this thread?
Did you have a chance to see and read my questions about my Dometic, posted here on this thread?
Raya and Robert,
I will do my best to answer the issues you guys so cleverly figured out...
First let me say this,
There is the world I live in, the technicians universe, its guided forcibly by insurance company studies and reports, their detailed suggestive information being fed into the R.V. industry resulting in volumes of future changes to the R.V. universe of the engineering...The guru to every problem is the engineer he owns every success or disaster that has ever impacted RV life.
This group is easy to find when the party is going on but hard to reach when the kitchen needs cleaning.
The engineer is the high priest of any design...
I cannot have an opinion contrary to them officially.
Their realm is sacred to them, their defenses are many, their considerable education worthy of recognition, the societies that they recognize and recognize them tower over me and act as look outs for the profession in general, they are also cannibals and eat technicians for lunch...
They are the guiding light to the service technician forever and ever.
Only in recent decades have engineers consorted with the lowly dirty technicians in the repair field for input into their designs or maintenance issues of the equipment they engineer.
Now much of any engineering is done over seas, by standardizing the rules, any C.A.D. Program in any part of the world can be hired to dream stuff up...Cheaper too.
Point made here is I will explain what I know to be true in as much of a non technical language as I can so the information is less mesmerizing.
Its meant to be down to earth, organic to R.V. only.
That said...
This is the basic theory of baffles...then there is the practice of the theory in real life conditions after the explanation.
Overview...
The baffle system was intended to take incoming cool air at the bottom of a refrigerator inducing the correct drafting effect required to supply the “condenser” hot fins with a supply of cooler air.
Goals...
To increase the systems efficiency to absorb heat energy we mix the warmer and cooler air layers inside the back compartment with baffles.
To get correct air flow across all the hot fins evenly and move the now warmed air in the right direction of flow we continue mixing the air correctly and increase its input velocity at the bottom. If we do this well we transfer the maximum amount of heat energy thru heat transfer of conduction from the hot fins...
Then overcoming any encountered resistance the air exits the system at the physical top of the chimney “the rear space” in the back of the refrigerator, the movement of this air is thru the principle of convection and the expansion of heated air.
Raya,
I love the words you used in your post when you referred to the "chimney effect". It really describes the mechanics being done, though we use terms like drafting as a descriptor I worked it into this explanation.
The theory of baffles is better understood if I describe what the sequence of operation is without baffles.
The first thing happening without baffles...The problem.
As the incoming air being drawn in waifs across the fins up the rear refrigerator cavity (chimney) to the vent at the top, the fins transfer heat from the warmer fins to the cooler air heating it up, the now lighter air moves out the vent we hope...Nice to say this, but it is to simple.
Because...
The air nearest to the fins gets hotter first, since the cooler air mass is moving in a good orderly direction slowly the closer air to the hot fins heats up faster exiting and pulling the cooler air out with it without the rest of the cooler inside the compartment picking up available excess heat from the fins.
Without baffles this is how it works, the air will speed up closer to the fins, but it will not mix well at all...This wastes volumes of cooler air within the compartment that will not come in contact with the hot fins starving for it.
The air needs to mix upwith cooler air, the heated air will not mix up inside by just slipping by the hot fins faster and faster by any real measure...Heat transfer needs to happen with all incoming available air!
The air towards the outer wall without baffles will measure much less in temperature than the air immediately touching the fins, that air is desperately needed...
A law of thermal dynamics states, “heat must move from a warmer to a cooler object”.
When the air touching the fins reaches the same temperature of the fins the energy STOPS moving, when this equalizing of the two temperatures occurs the transfer of energy from INSIDE the box stops too! Ergo hot food.
How do we get cooler air nearer the fins to increase the heat transfer?
Answer: Mix the warmer closer fin heated air layer with cooler non heated air nearer the skin of the trailer which is farther from the hotter fins...By mixing all surrounding air by swirling it around we harness more potential to transfer more heat energy away from the fins.)
(1) Mix How?
We create a closed space open on the top and the bottom at the back of the refrigerator...Then place baffles so the air must roll over the baffle causing the air to mix up by swirling the air current as it goes by the baffle, ([cavitation of air) this air begins to blend all the air warmer air closer to the fins (warm air layer) with the cooler air farther away from the fins (cooler air layer) lowering the over all temp (ambient temperature) of the air mass so the fins farther up the way have a greater Delta T or DT. (temperature difference) to keep transferring heat longer.
The greater the temperature difference of the contact air layer with the actual metal fins of the heat condenser heat exchanger the greater the heat transfer rate out of the system.
(2) The second thing going on...
That said...Lets go to Raya's "chimney effect" a good description because there is another thing going on back there with baffles and the incoming air which her descriptor clues us too.
Beyond mixing air temps?
The cooler air is coming in a nice big louvered door slowly...When it must squeeze a little past the first baffle beginning the cavitation or swirl effect cycle mixing the hot and cooler air another thing happens at the baffle.
Principle here...
"When a larger amount of air squeezes thru a smaller opening it must speed up, the tighter space available increases the velocity of the air moving."
Think a wide quiet stream of water transitioning to a narrow rapids)
Those of you who are engineers on FBRV be kind, I am trying to really simplify this.
Review:
The cavitation effect described earlier in (1) is now multiplied by simultaneously increasing the air velocity moving into the place of cavitation itself...Mixing the warmer and cooler air in zones better still, arguably also increasing the total of the air volume passing thru the compartment.
The direction the air wants to go is assisted by the now lighter expanded qualities of heated air (think hot air balloon).
And...
The baffle acts as an air mass back stop or a air check-valve, permitting easily the heated air moving in the desired direction (UP) but making it much harder for the heated air to reverse direction.
Then...
A tiny increase in air pressure via the gentle expansion of air increases ever so slightly above the baffle...This increase in static pressure of the upper refrigerator compartment/chimney ever so slightly lends again to the desired effect of moving air in a good orderly direction.
The new air properties in the upper compartment above the baffle partner together in a concert to encourage the correct direction of the heated, expanded, lighter air exhausted up and out thru a b]correctly sized vent over coming any resistance to it!!!!![/b]
I have NOT included the air currants blowing over the top of the vent system or chimney.
Now I will really shoot myself in the foot here and fall on my sword as a technician. In small systems like most fiberglass trailers these baffles really do not in practice make a hoot of difference in the field with tiny systems like in fiberglass trailers...The temperature swings in the climate zones we all camp in are far more influential in performance outcomes than the itsy bitsy baffles in our tiny spaces...
Except in the big expensive luxury refrigerators.
Not having baffles in new installations is good for voiding warranties...
Having baffles makes SURE manufacturers of R.V.s keep the back fins of the refrigerator off the compartment wall.
What Is Important is...
The size of the top vent and the lower door design must be matched to ensure the correct convective flow of air volume totals...[to often the vent is not the correct one.
I like .25 amp computer fans...even better the solar ones on that subject I want to say this, fans, any size of fan will suck more heat out than it can push, I put them on top of the heated air space and suck the air out. A tiny one is best, always line the space with an infra red reflective barrier, these refrigerators are built to handle sensible heat loads (heat that heats the air thru conduction) Refrigerators DO NOT handle insensible heat loads at all!!! (heat energy that does not raise the temp of air it passes thru BUT raises the temp of any object when it strikes, then the object warms the air) See infrared Heat definitions.
If you have a Burro like trailer, or a 13 foot Scamp-ish trailer with the under counter refrigerators using the side vents consider a solar or battery fan exhausting out the top vent in warmer climates.
If you are using a push pull fan (2 fans) put both of them in the top as exhaust fans, suck the air thru the system and exhaust the air... You can switch the fans independently so you can select low or high volume air exhaust. I do not like a fan blowing on the bottom as it may change the air fuel mix ratio of the burner by pressurizing the compartment or blow the pilot away from the thermocouple flame sensor...
ALSO BY PRESSURIZING THE REAR COMPARTMENT BY BLOWING AIR INTO IT CARBON MONOXIDE CAN BE MOVED INTO THE TRAILER.
Where fans are concerned exhaust only directly thru the vent.
Hope this helps.
Happy Camping, Safe Trails.
Harry
I will do my best to answer the issues you guys so cleverly figured out...
First let me say this,
There is the world I live in, the technicians universe, its guided forcibly by insurance company studies and reports, their detailed suggestive information being fed into the R.V. industry resulting in volumes of future changes to the R.V. universe of the engineering...The guru to every problem is the engineer he owns every success or disaster that has ever impacted RV life.
This group is easy to find when the party is going on but hard to reach when the kitchen needs cleaning.
The engineer is the high priest of any design...
I cannot have an opinion contrary to them officially.
Their realm is sacred to them, their defenses are many, their considerable education worthy of recognition, the societies that they recognize and recognize them tower over me and act as look outs for the profession in general, they are also cannibals and eat technicians for lunch...
They are the guiding light to the service technician forever and ever.
Only in recent decades have engineers consorted with the lowly dirty technicians in the repair field for input into their designs or maintenance issues of the equipment they engineer.
Now much of any engineering is done over seas, by standardizing the rules, any C.A.D. Program in any part of the world can be hired to dream stuff up...Cheaper too.
Point made here is I will explain what I know to be true in as much of a non technical language as I can so the information is less mesmerizing.
Its meant to be down to earth, organic to R.V. only.
That said...
This is the basic theory of baffles...then there is the practice of the theory in real life conditions after the explanation.
Overview...
The baffle system was intended to take incoming cool air at the bottom of a refrigerator inducing the correct drafting effect required to supply the “condenser” hot fins with a supply of cooler air.
Goals...
To increase the systems efficiency to absorb heat energy we mix the warmer and cooler air layers inside the back compartment with baffles.
To get correct air flow across all the hot fins evenly and move the now warmed air in the right direction of flow we continue mixing the air correctly and increase its input velocity at the bottom. If we do this well we transfer the maximum amount of heat energy thru heat transfer of conduction from the hot fins...
Then overcoming any encountered resistance the air exits the system at the physical top of the chimney “the rear space” in the back of the refrigerator, the movement of this air is thru the principle of convection and the expansion of heated air.
Raya,
I love the words you used in your post when you referred to the "chimney effect". It really describes the mechanics being done, though we use terms like drafting as a descriptor I worked it into this explanation.
The theory of baffles is better understood if I describe what the sequence of operation is without baffles.
The first thing happening without baffles...The problem.
As the incoming air being drawn in waifs across the fins up the rear refrigerator cavity (chimney) to the vent at the top, the fins transfer heat from the warmer fins to the cooler air heating it up, the now lighter air moves out the vent we hope...Nice to say this, but it is to simple.
Because...
The air nearest to the fins gets hotter first, since the cooler air mass is moving in a good orderly direction slowly the closer air to the hot fins heats up faster exiting and pulling the cooler air out with it without the rest of the cooler inside the compartment picking up available excess heat from the fins.
Without baffles this is how it works, the air will speed up closer to the fins, but it will not mix well at all...This wastes volumes of cooler air within the compartment that will not come in contact with the hot fins starving for it.
The air needs to mix upwith cooler air, the heated air will not mix up inside by just slipping by the hot fins faster and faster by any real measure...Heat transfer needs to happen with all incoming available air!
The air towards the outer wall without baffles will measure much less in temperature than the air immediately touching the fins, that air is desperately needed...
A law of thermal dynamics states, “heat must move from a warmer to a cooler object”.
When the air touching the fins reaches the same temperature of the fins the energy STOPS moving, when this equalizing of the two temperatures occurs the transfer of energy from INSIDE the box stops too! Ergo hot food.
How do we get cooler air nearer the fins to increase the heat transfer?
Answer: Mix the warmer closer fin heated air layer with cooler non heated air nearer the skin of the trailer which is farther from the hotter fins...By mixing all surrounding air by swirling it around we harness more potential to transfer more heat energy away from the fins.)
(1) Mix How?
We create a closed space open on the top and the bottom at the back of the refrigerator...Then place baffles so the air must roll over the baffle causing the air to mix up by swirling the air current as it goes by the baffle, ([cavitation of air) this air begins to blend all the air warmer air closer to the fins (warm air layer) with the cooler air farther away from the fins (cooler air layer) lowering the over all temp (ambient temperature) of the air mass so the fins farther up the way have a greater Delta T or DT. (temperature difference) to keep transferring heat longer.
The greater the temperature difference of the contact air layer with the actual metal fins of the heat condenser heat exchanger the greater the heat transfer rate out of the system.
(2) The second thing going on...
That said...Lets go to Raya's "chimney effect" a good description because there is another thing going on back there with baffles and the incoming air which her descriptor clues us too.
Beyond mixing air temps?
The cooler air is coming in a nice big louvered door slowly...When it must squeeze a little past the first baffle beginning the cavitation or swirl effect cycle mixing the hot and cooler air another thing happens at the baffle.
Principle here...
"When a larger amount of air squeezes thru a smaller opening it must speed up, the tighter space available increases the velocity of the air moving."
Think a wide quiet stream of water transitioning to a narrow rapids)
Those of you who are engineers on FBRV be kind, I am trying to really simplify this.
Review:
The cavitation effect described earlier in (1) is now multiplied by simultaneously increasing the air velocity moving into the place of cavitation itself...Mixing the warmer and cooler air in zones better still, arguably also increasing the total of the air volume passing thru the compartment.
The direction the air wants to go is assisted by the now lighter expanded qualities of heated air (think hot air balloon).
And...
The baffle acts as an air mass back stop or a air check-valve, permitting easily the heated air moving in the desired direction (UP) but making it much harder for the heated air to reverse direction.
Then...
A tiny increase in air pressure via the gentle expansion of air increases ever so slightly above the baffle...This increase in static pressure of the upper refrigerator compartment/chimney ever so slightly lends again to the desired effect of moving air in a good orderly direction.
The new air properties in the upper compartment above the baffle partner together in a concert to encourage the correct direction of the heated, expanded, lighter air exhausted up and out thru a b]correctly sized vent over coming any resistance to it!!!!![/b]
I have NOT included the air currants blowing over the top of the vent system or chimney.
Now I will really shoot myself in the foot here and fall on my sword as a technician. In small systems like most fiberglass trailers these baffles really do not in practice make a hoot of difference in the field with tiny systems like in fiberglass trailers...The temperature swings in the climate zones we all camp in are far more influential in performance outcomes than the itsy bitsy baffles in our tiny spaces...
Except in the big expensive luxury refrigerators.
Not having baffles in new installations is good for voiding warranties...
Having baffles makes SURE manufacturers of R.V.s keep the back fins of the refrigerator off the compartment wall.
What Is Important is...
The size of the top vent and the lower door design must be matched to ensure the correct convective flow of air volume totals...[to often the vent is not the correct one.
I like .25 amp computer fans...even better the solar ones on that subject I want to say this, fans, any size of fan will suck more heat out than it can push, I put them on top of the heated air space and suck the air out. A tiny one is best, always line the space with an infra red reflective barrier, these refrigerators are built to handle sensible heat loads (heat that heats the air thru conduction) Refrigerators DO NOT handle insensible heat loads at all!!! (heat energy that does not raise the temp of air it passes thru BUT raises the temp of any object when it strikes, then the object warms the air) See infrared Heat definitions.
If you have a Burro like trailer, or a 13 foot Scamp-ish trailer with the under counter refrigerators using the side vents consider a solar or battery fan exhausting out the top vent in warmer climates.
If you are using a push pull fan (2 fans) put both of them in the top as exhaust fans, suck the air thru the system and exhaust the air... You can switch the fans independently so you can select low or high volume air exhaust. I do not like a fan blowing on the bottom as it may change the air fuel mix ratio of the burner by pressurizing the compartment or blow the pilot away from the thermocouple flame sensor...
ALSO BY PRESSURIZING THE REAR COMPARTMENT BY BLOWING AIR INTO IT CARBON MONOXIDE CAN BE MOVED INTO THE TRAILER.
Where fans are concerned exhaust only directly thru the vent.
Hope this helps.
Happy Camping, Safe Trails.
Harry
Holy crap, Harry! That was awesome!
So, what I've gleaned from what you've written, that's directly applicable to my situation (small, under-counter fridge in a 13' Scamp), is this:
1 Properly matched, and appropriately sized, venting, top and bottom is imperative
2 Baffles, in theory, are okay--but in my configuration, not necessary, and probably ineffective
3 Using a small fan (or two, in a push-pull arrangement) at the top of the airspace (near fins) is a good thing
Do you concur?
RJ
So, what I've gleaned from what you've written, that's directly applicable to my situation (small, under-counter fridge in a 13' Scamp), is this:
1 Properly matched, and appropriately sized, venting, top and bottom is imperative
2 Baffles, in theory, are okay--but in my configuration, not necessary, and probably ineffective
3 Using a small fan (or two, in a push-pull arrangement) at the top of the airspace (near fins) is a good thing
Do you concur?
RJ
[My new text is in green so that I can put stuff in between Robert's quotes, and not have it all confusing.]
Harry,
Yeah, wow! I think you should be crowned
Click to view attachment
of Refrigerator Baffling. AND of explaining it.
I love engineers, and they do great things, but one should never underestimate real-world experience. Thank you!
Quick question: Would something like that metallic/air-bubble insulation be an example of a good infrared barrier sheet? If not, then can you name an example?
This is a great discussion.
Raya
Harry,
Yeah, wow! I think you should be crowned
Click to view attachment
of Refrigerator Baffling. AND of explaining it.
I love engineers, and they do great things, but one should never underestimate real-world experience. Thank you!
Quick question: Would something like that metallic/air-bubble insulation be an example of a good infrared barrier sheet? If not, then can you name an example?
QUOTE (Robert Johans @ Oct 17 2009, 12:34 PM)
So, what I've gleaned from what you've written, that's directly applicable to my situation (small, under-counter fridge in a 13' Scamp), is this:
1 Properly matched, and appropriately sized, venting, top and bottom is imperative
I have another question now: What are "properly matched and appropriately sized" vents? I have the Dometic vents, and the one at the bottom (large panel that you can remove to access "guts" of fridge) is probably twice the size of the one at the top (horizontal "ribbon" vent). I've seen this arrangement on many Bolers; I believe it is stock. Is this properly matched and sized?
2 Baffles, in theory, are okay--but in my configuration, not necessary, and probably ineffective
3 Using a small fan (or two, in a push-pull arrangement) at the top of the airspace (near fins) is a good thing
I got from Harry's post that both fans should be at the top, and that both should be exhausting (pulling). Harry, can you confirm which one it should be?
1 Properly matched, and appropriately sized, venting, top and bottom is imperative
I have another question now: What are "properly matched and appropriately sized" vents? I have the Dometic vents, and the one at the bottom (large panel that you can remove to access "guts" of fridge) is probably twice the size of the one at the top (horizontal "ribbon" vent). I've seen this arrangement on many Bolers; I believe it is stock. Is this properly matched and sized?
2 Baffles, in theory, are okay--but in my configuration, not necessary, and probably ineffective
3 Using a small fan (or two, in a push-pull arrangement) at the top of the airspace (near fins) is a good thing
I got from Harry's post that both fans should be at the top, and that both should be exhausting (pulling). Harry, can you confirm which one it should be?
This is a great discussion.
Raya
If you don't mind, Harry, check out this illustration showing exactly what I've got on my Scamp now. Please send me any advice applicable. Thanks.
I'm not Harry (and can't even come close to his advice - by about four orders of magnitude), but I still think you'd want both of those fans exhausting air (vs. the way you have it with one drawing in and one exhausting).
That's because I think you want the fact that the fans are pulling hot air up and out (both of them) to be what makes cold air come in at the bottom.
With them one going each way, and both at the top, I don't see any "reason" that cool air would want to come in at the bottom (not to anthropomorphize cool air...). It seems like your current way would just make for a little enclosed loop at the top, with the bottom all left out and lonely.
Harry?
Raya
That's because I think you want the fact that the fans are pulling hot air up and out (both of them) to be what makes cold air come in at the bottom.
With them one going each way, and both at the top, I don't see any "reason" that cool air would want to come in at the bottom (not to anthropomorphize cool air...). It seems like your current way would just make for a little enclosed loop at the top, with the bottom all left out and lonely.
Harry?
Raya
Robert,
Where is the top of the uppermost fins? In my case it was above the pre-existing vent, that is why I moved the upper vent to above the belly band and the top of the uppermost fins.
Where is the top of the uppermost fins? In my case it was above the pre-existing vent, that is why I moved the upper vent to above the belly band and the top of the uppermost fins.
Harry, that was a wonderfully detailed post. I know how much mental energy and time it takes to put that sort of thing together . . . thanks for taking the time and expending the energy.
--Peter
--Peter
Robert,
I love the drawing!!!
To #1 I agree.
To #2 I agree.
To #3 I would like to say that both fans should exhaust out the top, wire the fans to a single pole double throw switch...the middle position is off, switch up runs one exhaust and switch down runs two...Use computer fans (like C.P.U. fans, .25 to .75 amps) let the fans throw the air out the top vent, mount immediately under the vent blowing out...You will need to use them day time only.
You can buy the little solar fan for daytime use and use the other as a backup for cloudy days or a boost in the god awful heat. See ebay they make a solar refrigerator fan, it comes with the solar panel.
Your on the right track, You ideas are sound, you need to understand you can PULL more air thru the compartment than you can push with the same size fan fan.
Happy Camping, Safe Trails.
Harry
I love the drawing!!!
To #1 I agree.
To #2 I agree.
To #3 I would like to say that both fans should exhaust out the top, wire the fans to a single pole double throw switch...the middle position is off, switch up runs one exhaust and switch down runs two...Use computer fans (like C.P.U. fans, .25 to .75 amps) let the fans throw the air out the top vent, mount immediately under the vent blowing out...You will need to use them day time only.
You can buy the little solar fan for daytime use and use the other as a backup for cloudy days or a boost in the god awful heat. See ebay they make a solar refrigerator fan, it comes with the solar panel.
Your on the right track, You ideas are sound, you need to understand you can PULL more air thru the compartment than you can push with the same size fan fan.
Happy Camping, Safe Trails.
Harry
QUOTE (Robert Johans @ Oct 17 2009, 09:34 AM)
Holy crap, Harry! That was awesome!
So, what I've gleaned from what you've written, that's directly applicable to my situation (small, under-counter fridge in a 13' Scamp), is this:
1 Properly matched, and appropriately sized, venting, top and bottom is imperative
2 Baffles, in theory, are okay--but in my configuration, not necessary, and probably ineffective
3 Using a small fan (or two, in a push-pull arrangement) at the top of the airspace (near fins) is a good thing
Do you concur?
RJ
So, what I've gleaned from what you've written, that's directly applicable to my situation (small, under-counter fridge in a 13' Scamp), is this:
1 Properly matched, and appropriately sized, venting, top and bottom is imperative
2 Baffles, in theory, are okay--but in my configuration, not necessary, and probably ineffective
3 Using a small fan (or two, in a push-pull arrangement) at the top of the airspace (near fins) is a good thing
Do you concur?
RJ
Peter,
I have always enjoyed your posts, and the pics of your work.
A moderator must have cleaned up my different fonts off the two laptops I was using.
(Thanks moderator)
Harry
I have always enjoyed your posts, and the pics of your work.
A moderator must have cleaned up my different fonts off the two laptops I was using.
(Thanks moderator)
Harry
QUOTE (peterh @ Oct 17 2009, 09:26 PM)
Harry, that was a wonderfully detailed post. I know how much mental energy and time it takes to put that sort of thing together . . . thanks for taking the time and expending the energy.
--Peter
--Peter
Bang on Raya...
QUOTE (Raya L. @ Oct 17 2009, 05:20 PM)
I'm not Harry (and can't even come close to his advice - by about four orders of magnitude), but I still think you'd want both of those fans exhausting air (vs. the way you have it with one drawing in and one exhausting).
That's because I think you want the fact that the fans are pulling hot air up and out (both of them) to be what makes cold air come in at the bottom.
With them one going each way, and both at the top, I don't see any "reason" that cool air would want to come in at the bottom (not to anthropomorphize cool air...). It seems like your current way would just make for a little enclosed loop at the top, with the bottom all left out and lonely.
Harry?
Raya
That's because I think you want the fact that the fans are pulling hot air up and out (both of them) to be what makes cold air come in at the bottom.
With them one going each way, and both at the top, I don't see any "reason" that cool air would want to come in at the bottom (not to anthropomorphize cool air...). It seems like your current way would just make for a little enclosed loop at the top, with the bottom all left out and lonely.
Harry?
Raya
Raya,
I love the bubble wrap...
I personally use foil backed engine firewall spun fiberglass heat shield, its spun fiberglass tightly compacted that has a foil reflective barrier...This is a personal thing I do, B-Wrap is fine, the reason I use the other is IF I ever had a fire, the spun fiberglass would contain the fire longer and allow me to get a fire extinguisher.
Happy Camping, Safe Trails.
I should not be crowned Raya, I am bored stiff...
I go to surgery Tuesday the 20th and your wonderful question keeps me sane...
I would rather be camping!!!
If not that I will natter.
Harry
I love the bubble wrap...
I personally use foil backed engine firewall spun fiberglass heat shield, its spun fiberglass tightly compacted that has a foil reflective barrier...This is a personal thing I do, B-Wrap is fine, the reason I use the other is IF I ever had a fire, the spun fiberglass would contain the fire longer and allow me to get a fire extinguisher.
Happy Camping, Safe Trails.
I should not be crowned Raya, I am bored stiff...
I go to surgery Tuesday the 20th and your wonderful question keeps me sane...
I would rather be camping!!!
If not that I will natter.
Harry
QUOTE (Raya L. @ Oct 17 2009, 10:10 AM)
[My new text is in green so that I can put stuff in between Robert's quotes, and not have it all confusing.]
Harry,
Yeah, wow! I think you should be crowned
Click to view attachment
of Refrigerator Baffling. AND of explaining it.
I love engineers, and they do great things, but one should never underestimate real-world experience. Thank you!
Quick question: Would something like that metallic/air-bubble insulation be an example of a good infrared barrier sheet? If not, then can you name an example?
This is a great discussion.
Raya
Harry,
Yeah, wow! I think you should be crowned
Click to view attachment
of Refrigerator Baffling. AND of explaining it.
I love engineers, and they do great things, but one should never underestimate real-world experience. Thank you!
Quick question: Would something like that metallic/air-bubble insulation be an example of a good infrared barrier sheet? If not, then can you name an example?
This is a great discussion.
Raya
Harry,
I hope you're up and about and camping ASAP after your surgery
Your out-of-the-way-place camping reports are great, too 
Until then, if you really are bored, can you explain what you meant by properly sized vents? Real-world, the Bolers are pretty limited (unless one were to put in a chimney/pipe), but I do notice they usually have a larger vent at the bottom (Dometic) and then a smaller one up top (either just below or just above the belly band).
Is the larger/lower smaller/upper the right general idea?
again!
I hope you're up and about and camping ASAP after your surgery
Your out-of-the-way-place camping reports are great, too Until then, if you really are bored, can you explain what you meant by properly sized vents? Real-world, the Bolers are pretty limited (unless one were to put in a chimney/pipe), but I do notice they usually have a larger vent at the bottom (Dometic) and then a smaller one up top (either just below or just above the belly band).
Is the larger/lower smaller/upper the right general idea?
again!
QUOTE (Harry Young @ Oct 18 2009, 01:24 AM)
you need to understand you can PULL more air thru the compartment than you can push with the same size fan fan.
Harry,
Thanks for that comment. You've made up my mind on how to add my fans. My fridge has a small fan built in at the bottom that needs replacing. It is controlled by a thermocouple attached to the fins. You can see it in the picture I posted earlier connected to the blue and yellow wires:
http://www.fiberglassrv.com/board/index.ph...st&id=17779
I'll disconnect the original fan and use that wiring for the computer fans in the upper compartment. I remember reading somewhere that if one connects the fans in series they run slower and draw less power. But that was in reference to the larger 12V computer case cooling fans. Any thoughts on that, with respect to both power and cooling efficiency?
Best wishes for your health.
Roger,
If you look at the picture (link above) you'll see how much room you have for vents above the belly band. You've got about an inch less in height from the rivets for the lower kitchen cabinet.
Raya,
As a reference, check out the photo of my vent set-up on my Scamp.
These vents are the ones spec'd by Dometic to fit the small 1.9cuin 2190 model that I have. You can see that the upper vent isn't that much smaller than the lower. I was able to keep the upper vent below my belly band and still keep it positioned slightly above my fridge cooling fins.
Hope this helps...
As a reference, check out the photo of my vent set-up on my Scamp.
These vents are the ones spec'd by Dometic to fit the small 1.9cuin 2190 model that I have. You can see that the upper vent isn't that much smaller than the lower. I was able to keep the upper vent below my belly band and still keep it positioned slightly above my fridge cooling fins.
Hope this helps...
QUOTE (Roy in TO @ Oct 17 2009, 06:40 PM)
Robert,
Where is the top of the uppermost fins? In my case it was above the pre-existing vent, that is why I moved the upper vent to above the belly band and the top of the uppermost fins.
Where is the top of the uppermost fins? In my case it was above the pre-existing vent, that is why I moved the upper vent to above the belly band and the top of the uppermost fins.
Roy,
Since the fridge install was recent, I was able to put my venting exactly where I felt they should go. My cooling fins are just a couple inches below the top of the fridge (approx. 22" off the floor). They are also centered behind my upper vent. (See bellow.)
QUOTE (Robert Johans @ Oct 18 2009, 12:29 PM)
As a reference, check out the photo of my vent set-up on my Scamp.
These vents are the ones spec'd by Dometic to fit the small 1.9cuin 2190 model that I have.
These vents are the ones spec'd by Dometic to fit the small 1.9cuin 2190 model that I have.
Hi Robert,
Thant looks similar to the vent set-up for my Dometic fridge too, and is what's on my Boler. I was just curious about Harry's take on it, since he's got Real World experience that may or may not agree with what the manufacturer suggested.
Raya
These crappy fridges can't cool anything if its over 90 degrees especially after the flame blows out on the hiway.
Bring an ice chest and don't expect too much even if it has a fan.
These Dometics have many problems-feeble door latch-flame out-need interior and external venting-worthless 12V cooling to name the worst.
Sorry to be so negative but that's reality.
Bring an ice chest and don't expect too much even if it has a fan.
These Dometics have many problems-feeble door latch-flame out-need interior and external venting-worthless 12V cooling to name the worst.
Sorry to be so negative but that's reality.
Jim,
Nothing wrong with reality, but others seem to have good experiences with their Dometic 3-way fridges. I'm sure they are challenged when it's over 90 degrees though. I'm just curious: Does yours also have problems cooling in that hot weather if it is plugged in to shore power (I realize it uses the same cooling mechanism then)?
Also, I think they mean for you to run it via 12v connection when you are underway, if I'm not mistaken.
I suppose a "regular" electric fridge, with a compressor (vs. absorption) would work better in really hot weather, but it's so nice to be able to run it on propane, and the silence is great too (in my opinion).
Has your installation been modified in the ways that Harry suggests? How much did that help compared to the stock installation?
Raya
PS: If you really do decide to get rid of it, please advertise it here, as I don't believe one can get parts for the original Dometics we had in our older eggs (2100 model, going by memory).
Nothing wrong with reality, but others seem to have good experiences with their Dometic 3-way fridges. I'm sure they are challenged when it's over 90 degrees though. I'm just curious: Does yours also have problems cooling in that hot weather if it is plugged in to shore power (I realize it uses the same cooling mechanism then)?
Also, I think they mean for you to run it via 12v connection when you are underway, if I'm not mistaken.
I suppose a "regular" electric fridge, with a compressor (vs. absorption) would work better in really hot weather, but it's so nice to be able to run it on propane, and the silence is great too (in my opinion).
Has your installation been modified in the ways that Harry suggests? How much did that help compared to the stock installation?
Raya
PS: If you really do decide to get rid of it, please advertise it here, as I don't believe one can get parts for the original Dometics we had in our older eggs (2100 model, going by memory).
QUOTE (Raya L. @ Oct 18 2009, 10:42 AM)
Jim,
Nothing wrong with reality, but others seem to have good experiences with their Dometic 3-way fridges. I'm sure they are challenged when it's over 90 degrees though. I'm just curious: Does yours also have problems cooling in that hot weather if it is plugged in to shore power (I realize it uses the same cooling mechanism then)?
Also, I think they mean for you to run it via 12v connection when you are underway, if I'm not mistaken.
I suppose a "regular" electric fridge, with a compressor (vs. absorption) would work better in really hot weather, but it's so nice to be able to run it on propane, and the silence is great too (in my opinion).
Has your installation been modified in the ways that Harry suggests? How much did that help compared to the stock installation?
Raya
PS: If you really do decide to get rid of it, please advertise it here, as I don't believe one can get parts for the original Dometics we had in our older eggs (2100 model, going by memory).
Nothing wrong with reality, but others seem to have good experiences with their Dometic 3-way fridges. I'm sure they are challenged when it's over 90 degrees though. I'm just curious: Does yours also have problems cooling in that hot weather if it is plugged in to shore power (I realize it uses the same cooling mechanism then)?
Also, I think they mean for you to run it via 12v connection when you are underway, if I'm not mistaken.
I suppose a "regular" electric fridge, with a compressor (vs. absorption) would work better in really hot weather, but it's so nice to be able to run it on propane, and the silence is great too (in my opinion).
Has your installation been modified in the ways that Harry suggests? How much did that help compared to the stock installation?
Raya
PS: If you really do decide to get rid of it, please advertise it here, as I don't believe one can get parts for the original Dometics we had in our older eggs (2100 model, going by memory).
I concur with Raya...
My first outing with my Scamp renovation, and new Dometic, was super.
I followed the advice of those here on the forum and pre-cooled my fridge with 120v before I left home. Then switched over to 12v for the four hour drive the the NOG we just put on here in Oregon. By the time I got to my camp site and unhitched, I found the beer nearly frozen! Shore power kept things cool for the duration. Of course, it wasn't 90 degrees, but I'm quite confident that the fridge will work as designed.
That said, and as you may have gathered from reading this thread, I did put a lot of thought into my entire fridge configuration, including the insulated shroud that reduces the effects (I'm told) of ambient heat.
RJ
My fridge is about 3 years old-freezer not included on new models.
Never does much on 12V even with a 10ga. wire. On 110 fairly well.
Has the little fan like promoted here.
I glued a 2 in. foam board under the trailer floor-maybe helped a little.
The basic problem is there is not enough insulation outside. But that would require more space.
Look at a household propane fridge-it is huge!
I've never read any discussion about the blowout problem.
I put in perforated aluminum behind the louvers openings-no help.
Now I'm trying pink wool wads stuffed in cracks in the flame area-not tested yet.
Never does much on 12V even with a 10ga. wire. On 110 fairly well.
Has the little fan like promoted here.
I glued a 2 in. foam board under the trailer floor-maybe helped a little.
The basic problem is there is not enough insulation outside. But that would require more space.
Look at a household propane fridge-it is huge!
I've never read any discussion about the blowout problem.
I put in perforated aluminum behind the louvers openings-no help.
Now I'm trying pink wool wads stuffed in cracks in the flame area-not tested yet.
Hi Jim,
Yeah, the freezer is nice. Plus, the newer units are deeper, and stick out into the trailer.
On the perforated aluminum: It seems like the main issue with our units is getting the heat to exhaust (since what the fridge is really doing is removing heat). It gets out of the fridge but then has a hard time getting out of the trailer because we don't have "real" chimneys but only little vents.
I would think that perhaps the perforated aluminum is actually reducing airflow coming in (can't see it, so just postulating), further reducing the chimney/cooling.
I think if it were me, I would give up on using propane when driving, and would try to get the heat to more effectively transfer out of the surround.
Do you have two fans, as Harry suggested, and are they both at the top of the enclosure, and both exausting? It sounds like that is the way to go.
I wonder if there is a specific problem with your 12-volt operation, or if it is related to the general "hot air not exausting" issue?
Raya
Yeah, the freezer is nice. Plus, the newer units are deeper, and stick out into the trailer.
On the perforated aluminum: It seems like the main issue with our units is getting the heat to exhaust (since what the fridge is really doing is removing heat). It gets out of the fridge but then has a hard time getting out of the trailer because we don't have "real" chimneys but only little vents.
I would think that perhaps the perforated aluminum is actually reducing airflow coming in (can't see it, so just postulating), further reducing the chimney/cooling.
I think if it were me, I would give up on using propane when driving, and would try to get the heat to more effectively transfer out of the surround.
Do you have two fans, as Harry suggested, and are they both at the top of the enclosure, and both exausting? It sounds like that is the way to go.
I wonder if there is a specific problem with your 12-volt operation, or if it is related to the general "hot air not exausting" issue?
Raya
Just pitching in here,
On the older Dometics, they were not dual carb units, the new ones are so they are less sensitive to angles as the old generation, Norcold as well...
The pictures are great, in the ones I have seen I can see you are not using the Dometic access doors?...On the older trailers the louvers poke out so rain water sheds off it efficiently. The new design the louvers poke in forming scoops.
These older doors suck, they void warranties too.
There is an important design innovation to these side saddle mounted refrigerators that have come up the production line in the last decade.
It seems F.B.R.V. folks are not aware of it for what it is.
Its not just a new fancy door?
The new lower door design and matching new upper design uses an inside out scoop intrinsic to the doors venting system greatly improving heat transfer.
This is really important to the operation of side saddle mount installations.
I will try to post pics to this design at the bottom.
As hot condenser air rises in the new design doors a portion of the warm air is scooped up with the louvers from inside the space and thrown away.
The new louvers "cup" away air as it rises
Dometic requires this door vent system on all installations, it works much better than the old louvered door of old. As an installer I must upgrade to this system with each NEW install or void warranties.
Side saddle venting arrangements like I saw in the in the pics lock more heat into the compartments because the louver faces outward, maker the interior wall smooth to air.
Look at the pics, imagine you are hot air sliding and rising becoming lighter and lighter, looking at the new design ask yourself what happens to you when you brush up against the new design?
On the older Dometics, they were not dual carb units, the new ones are so they are less sensitive to angles as the old generation, Norcold as well...
The pictures are great, in the ones I have seen I can see you are not using the Dometic access doors?...On the older trailers the louvers poke out so rain water sheds off it efficiently. The new design the louvers poke in forming scoops.
These older doors suck, they void warranties too.
There is an important design innovation to these side saddle mounted refrigerators that have come up the production line in the last decade.
It seems F.B.R.V. folks are not aware of it for what it is.
Its not just a new fancy door?
The new lower door design and matching new upper design uses an inside out scoop intrinsic to the doors venting system greatly improving heat transfer.
This is really important to the operation of side saddle mount installations.
I will try to post pics to this design at the bottom.
As hot condenser air rises in the new design doors a portion of the warm air is scooped up with the louvers from inside the space and thrown away.
The new louvers "cup" away air as it rises
Dometic requires this door vent system on all installations, it works much better than the old louvered door of old. As an installer I must upgrade to this system with each NEW install or void warranties.
Side saddle venting arrangements like I saw in the in the pics lock more heat into the compartments because the louver faces outward, maker the interior wall smooth to air.
Look at the pics, imagine you are hot air sliding and rising becoming lighter and lighter, looking at the new design ask yourself what happens to you when you brush up against the new design?
That's interesting, Harry. Makes sense, too!
Those louvers are completely the opposite of what is on the older Bolers; it's exactly as you described.
For replacing the older louvers with the newer ones, is it more important to replace the bottom or the top or both? (I'm guessing based on what you said that the top one is more critical...)
Raya
Those louvers are completely the opposite of what is on the older Bolers; it's exactly as you described.
For replacing the older louvers with the newer ones, is it more important to replace the bottom or the top or both? (I'm guessing based on what you said that the top one is more critical...)
Raya
I would do both, but if I had to choose the top is non negotiable, a must.
Harry
Harry
QUOTE (Raya L. @ Oct 18 2009, 06:23 PM)
That's interesting, Harry. Makes sense, too!
Those louvers are completely the opposite of what is on the older Bolers; it's exactly as you described.
For replacing the older louvers with the newer ones, is it more important to replace the bottom or the top or both? (I'm guessing based on what you said that the top one is more critical...)
Raya
Those louvers are completely the opposite of what is on the older Bolers; it's exactly as you described.
For replacing the older louvers with the newer ones, is it more important to replace the bottom or the top or both? (I'm guessing based on what you said that the top one is more critical...)
Raya
I'm definitely going to replace the top vent then. The bottom one is a nice one that opens, etc. but the top is nothing special so it's a no-brainer.
Are these Dometic brand vents? Or can you name a source?
Thanks - this is going to be a great reference thread!
Raya
Are these Dometic brand vents? Or can you name a source?
Thanks - this is going to be a great reference thread!
Raya
http://cgi.ebay.com/ebaymotors/ws/eBayISAP...;category=50069
Raya,
I buy at eBay often, the lower door in this style opens, the top in this style stays closed when bought as the set...What I do is I use two lower doors so BOTH open.
I like to be able to clean the upper compartment without disassembling the trailer!
Also I can service the small fan in mine at the top.
Happy Camping, Safe Trails.
Harry
Raya,
I buy at eBay often, the lower door in this style opens, the top in this style stays closed when bought as the set...What I do is I use two lower doors so BOTH open.
I like to be able to clean the upper compartment without disassembling the trailer!
Also I can service the small fan in mine at the top.
Happy Camping, Safe Trails.
Harry
QUOTE (Raya L. @ Oct 18 2009, 07:21 PM)
I'm definitely going to replace the top vent then. The bottom one is a nice one that opens, etc. but the top is nothing special so it's a no-brainer.
Are these Dometic brand vents? Or can you name a source?
Thanks - this is going to be a great reference thread!
Raya
Are these Dometic brand vents? Or can you name a source?
Thanks - this is going to be a great reference thread!
Raya
Harry,
Since it sounds like you've sourced quite a few refrigerator vents, I wonder if you know if it is possible to get metal ones? I went to look at the eBay ones you linked to, and I see that they are genuine Dometic, but I'm a bit hesitant to replace metal vents (that are still in good shape after 35 years) with plastic ones.
Now these may be a better plastic - and I see they can be painted - but in general I've been disappointed with RV plastic parts (such as the electrical cord access door that is completely degraded).
I'd like to get the new style vent for efficiency, but I'm going to try to find metal ones. If you know of a source, great. And/or if I find one, I'll post it here.
Raya
Since it sounds like you've sourced quite a few refrigerator vents, I wonder if you know if it is possible to get metal ones? I went to look at the eBay ones you linked to, and I see that they are genuine Dometic, but I'm a bit hesitant to replace metal vents (that are still in good shape after 35 years) with plastic ones.
Now these may be a better plastic - and I see they can be painted - but in general I've been disappointed with RV plastic parts (such as the electrical cord access door that is completely degraded).
I'd like to get the new style vent for efficiency, but I'm going to try to find metal ones. If you know of a source, great. And/or if I find one, I'll post it here.
Raya
QUOTE (jim munson @ Oct 18 2009, 01:34 PM)
... fridges can't cool anything if its over 90 degrees
...worthless 12V cooling
...
Sorry to be so negative but that's reality.
...worthless 12V cooling
...
Sorry to be so negative but that's reality.
FWIW
Mine now makes ice in the 90's on 120V and propane. The 12V is better suited to maintain cooling while travelling. My fridge was designed to run on propane with a sealed combustion chamber with separate intake/exhaust vents. The propane works better than the 12V while travelling.
Maybe it's due to different models.
Who knows. I'm happy.
Roy
Raya,
The answer is Yes and No,
I have a source where any custom door is made for me (louver machines are very expensive) but you get a conventional door like what you have, I think?
I guess the best approach would be to lay out the 24 dollars for the molded plastic one, then go to a sheet metal shop or send it to the custom cargo door maker I used and say can you get close to this stressing the cup feature in the Dometic plastic door? Or call Dometic and see if they source you to a party who can.
I have done this with ancient wheel well covers and some heater covers with success, the people in these trades always surprise me with what they can do.
While I have had sheet metal as part of my business I am in the stone age when it comes to louvers.
Happy Camping, Safe Trails.
Harry
The answer is Yes and No,
I have a source where any custom door is made for me (louver machines are very expensive) but you get a conventional door like what you have, I think?
I guess the best approach would be to lay out the 24 dollars for the molded plastic one, then go to a sheet metal shop or send it to the custom cargo door maker I used and say can you get close to this stressing the cup feature in the Dometic plastic door? Or call Dometic and see if they source you to a party who can.
I have done this with ancient wheel well covers and some heater covers with success, the people in these trades always surprise me with what they can do.
While I have had sheet metal as part of my business I am in the stone age when it comes to louvers.
Happy Camping, Safe Trails.
Harry
QUOTE (Raya L. @ Oct 18 2009, 09:17 PM)
Harry,
Since it sounds like you've sourced quite a few refrigerator vents, I wonder if you know if it is possible to get metal ones? I went to look at the eBay ones you linked to, and I see that they are genuine Dometic, but I'm a bit hesitant to replace metal vents (that are still in good shape after 35 years) with plastic ones.
Now these may be a better plastic - and I see they can be painted - but in general I've been disappointed with RV plastic parts (such as the electrical cord access door that is completely degraded).
I'd like to get the new style vent for efficiency, but I'm going to try to find metal ones. If you know of a source, great. And/or if I find one, I'll post it here.
Raya
Since it sounds like you've sourced quite a few refrigerator vents, I wonder if you know if it is possible to get metal ones? I went to look at the eBay ones you linked to, and I see that they are genuine Dometic, but I'm a bit hesitant to replace metal vents (that are still in good shape after 35 years) with plastic ones.
Now these may be a better plastic - and I see they can be painted - but in general I've been disappointed with RV plastic parts (such as the electrical cord access door that is completely degraded).
I'd like to get the new style vent for efficiency, but I'm going to try to find metal ones. If you know of a source, great. And/or if I find one, I'll post it here.
Raya
Raya,
I understand the disappointment in the plastic parts, the new parts coming out of China are beginning to be blended plastics, they have their issues but the different plastics in the recipe lend positive qualities now to the product. I would paint the vent with a U.V. coating to toughen it up to the sun here, the cold shatter issue there is no defense against in really cold climates. The design I would like to see these guys make is make a flexible silicon one, it takes the sun, the heat and the cold, bump it there are no dents or cracks in the cold.
Harry
I understand the disappointment in the plastic parts, the new parts coming out of China are beginning to be blended plastics, they have their issues but the different plastics in the recipe lend positive qualities now to the product. I would paint the vent with a U.V. coating to toughen it up to the sun here, the cold shatter issue there is no defense against in really cold climates. The design I would like to see these guys make is make a flexible silicon one, it takes the sun, the heat and the cold, bump it there are no dents or cracks in the cold.
Harry
QUOTE (Raya L. @ Oct 18 2009, 09:17 PM)
Harry,
Since it sounds like you've sourced quite a few refrigerator vents, I wonder if you know if it is possible to get metal ones? I went to look at the eBay ones you linked to, and I see that they are genuine Dometic, but I'm a bit hesitant to replace metal vents (that are still in good shape after 35 years) with plastic ones.
Now these may be a better plastic - and I see they can be painted - but in general I've been disappointed with RV plastic parts (such as the electrical cord access door that is completely degraded).
I'd like to get the new style vent for efficiency, but I'm going to try to find metal ones. If you know of a source, great. And/or if I find one, I'll post it here.
Raya
Since it sounds like you've sourced quite a few refrigerator vents, I wonder if you know if it is possible to get metal ones? I went to look at the eBay ones you linked to, and I see that they are genuine Dometic, but I'm a bit hesitant to replace metal vents (that are still in good shape after 35 years) with plastic ones.
Now these may be a better plastic - and I see they can be painted - but in general I've been disappointed with RV plastic parts (such as the electrical cord access door that is completely degraded).
I'd like to get the new style vent for efficiency, but I'm going to try to find metal ones. If you know of a source, great. And/or if I find one, I'll post it here.
Raya
QUOTE (Harry Young @ Oct 18 2009, 08:28 PM)
http://cgi.ebay.com/ebaymotors/ws/eBayISAP...;category=50069
Raya,
I buy at eBay often, the lower door in this style opens, the top in this style stays closed when bought as the set...What I do is I use two lower doors so BOTH open.
I like to be able to clean the upper compartment without disassembling the trailer!
Also I can service the small fan in mine at the top.
Happy Camping, Safe Trails.
Harry
Raya,
I buy at eBay often, the lower door in this style opens, the top in this style stays closed when bought as the set...What I do is I use two lower doors so BOTH open.
I like to be able to clean the upper compartment without disassembling the trailer!
Also I can service the small fan in mine at the top.
Happy Camping, Safe Trails.
Harry
Harry,
Are you suggesting to use this one vent door you've spec'd for both top and bottom? I can't identify any locking/closure hardware in the photos shown on the eBay link. What holds it closed?
Robert, 
Two locking screws on the side release the door.
Be advised these doors come in different sizes and latching options.
(example of different sizes)
http://cgi.ebay.com/ebaymotors/NEW-RV-DOME...COVER-DOOR_W0QQ
Also these come in different latch configurations.
Some of the big electronic RV box stores like PPL RV sell variations, these are all ok as long as the venting is in the inward style louver, Dometic can sell doors too.
(I was showing a single example of the correct side vent louver construction for side saddle refrigerator installs where top venting is not possible.)
I recommend both vents be the type that can easily pop opened for servicing top and bottom sections of the install.
I did not mean the one example I featured was the only way to go, or the size you need, as you see from the link above they come in different sizes.
I was trying to get F.B.R.V. members to note that Dometic really did make a move forward in side saddle venting with respect to exit hot air that older trailers should think over.
I like the rain proofing of the old design better, but its no good if the refrigerator will not work well?
If I were back in Washington State or Alaska again I would put a drip cap over my newer Dometic doors if I were stuck side saddle regarding the refrigeration of my trailer.
Look around at the choices, if you have any questions feel free to P.M. me.
Thanks for a great thread.
Happy Camping, Safe Trails.
Harry
Two locking screws on the side release the door.
Be advised these doors come in different sizes and latching options.
(example of different sizes)
http://cgi.ebay.com/ebaymotors/NEW-RV-DOME...COVER-DOOR_W0QQ
Also these come in different latch configurations.
Some of the big electronic RV box stores like PPL RV sell variations, these are all ok as long as the venting is in the inward style louver, Dometic can sell doors too.
(I was showing a single example of the correct side vent louver construction for side saddle refrigerator installs where top venting is not possible.)
I recommend both vents be the type that can easily pop opened for servicing top and bottom sections of the install.
I did not mean the one example I featured was the only way to go, or the size you need, as you see from the link above they come in different sizes.
I was trying to get F.B.R.V. members to note that Dometic really did make a move forward in side saddle venting with respect to exit hot air that older trailers should think over.
I like the rain proofing of the old design better, but its no good if the refrigerator will not work well?
If I were back in Washington State or Alaska again I would put a drip cap over my newer Dometic doors if I were stuck side saddle regarding the refrigeration of my trailer.
Look around at the choices, if you have any questions feel free to P.M. me.
Thanks for a great thread.
Happy Camping, Safe Trails.
Harry
QUOTE (Robert Johans @ Oct 19 2009, 08:30 AM)
Harry,
Are you suggesting to use this one vent door you've spec'd for both top and bottom? I can't identify any locking/closure hardware in the photos shown on the eBay link. What holds it closed?
Are you suggesting to use this one vent door you've spec'd for both top and bottom? I can't identify any locking/closure hardware in the photos shown on the eBay link. What holds it closed?
To All, 
On the subject of the Newer Dometic doors in this thread...
I must also in all fairness state that snow will get in them, driving rain is an issue too...
To still use the better door for warm weather operations of a Dometic refrigerator I have had to deal with this issue.
I have installed pop snaps onto the trailer wall and made in the past a vinyl storage cover to snap on for long term stowage.
I have seem pre-made travel covers, but for the life of me I cannot find them now.
You might need to give thought to this issue ahead of time, such as a long wet nasty drive ect.
As a service person I have seen water damage in the rear compartment because of this door designs very open features.
Likewise I have ALSO witnessed the very much improved operation of the refrigeration in side saddle installed refrigeration.
I recommend these doors for that delema...I prefer where possible the old doors and top venting.
This seems the devil one must pay to get the benefits for warm weather operation.
Consideration and planning should mitigate the drawbacks of this door design once its understood.
Happy Camping, Safe Trails.
Harry
On the subject of the Newer Dometic doors in this thread...
I must also in all fairness state that snow will get in them, driving rain is an issue too...
To still use the better door for warm weather operations of a Dometic refrigerator I have had to deal with this issue.
I have installed pop snaps onto the trailer wall and made in the past a vinyl storage cover to snap on for long term stowage.
I have seem pre-made travel covers, but for the life of me I cannot find them now.
You might need to give thought to this issue ahead of time, such as a long wet nasty drive ect.
As a service person I have seen water damage in the rear compartment because of this door designs very open features.
Likewise I have ALSO witnessed the very much improved operation of the refrigeration in side saddle installed refrigeration.
I recommend these doors for that delema...I prefer where possible the old doors and top venting.
This seems the devil one must pay to get the benefits for warm weather operation.
Consideration and planning should mitigate the drawbacks of this door design once its understood.
Happy Camping, Safe Trails.
Harry
QUOTE (Harry Young @ Oct 19 2009, 09:13 AM)
Robert,
Two locking screws on the side release the door.
Be advised these doors come in different sizes and latching options.
(example of different sizes)
http://cgi.ebay.com/ebaymotors/NEW-RV-DOME...COVER-DOOR_W0QQ
Also these come in different latch configurations.
Some of the big electronic RV box stores like PPL RV sell variations, these are all ok as long as the venting is in the inward style louver, Dometic can sell doors too.
(I was showing a single example of the correct side vent louver construction for side saddle refrigerator installs where top venting is not possible.)
I recommend both vents be the type that can easily pop opened for servicing top and bottom sections of the install.
I did not mean the one example I featured was the only way to go, or the size you need, as you see from the link above they come in different sizes.
I was trying to get F.B.R.V. members to note that Dometic really did make a move forward in side saddle venting with respect to exit hot air that older trailers should think over.
I like the rain proofing of the old design better, but its no good if the refrigerator will not work well?
If I were back in Washington State or Alaska again I would put a drip cap over my newer Dometic doors if I were stuck side saddle regarding the refrigeration of my trailer.
Look around at the choices, if you have any questions feel free to P.M. me.
Thanks for a great thread.
Happy Camping, Safe Trails.
Harry
Two locking screws on the side release the door.
Be advised these doors come in different sizes and latching options.
(example of different sizes)
http://cgi.ebay.com/ebaymotors/NEW-RV-DOME...COVER-DOOR_W0QQ
Also these come in different latch configurations.
Some of the big electronic RV box stores like PPL RV sell variations, these are all ok as long as the venting is in the inward style louver, Dometic can sell doors too.
(I was showing a single example of the correct side vent louver construction for side saddle refrigerator installs where top venting is not possible.)
I recommend both vents be the type that can easily pop opened for servicing top and bottom sections of the install.
I did not mean the one example I featured was the only way to go, or the size you need, as you see from the link above they come in different sizes.
I was trying to get F.B.R.V. members to note that Dometic really did make a move forward in side saddle venting with respect to exit hot air that older trailers should think over.
I like the rain proofing of the old design better, but its no good if the refrigerator will not work well?
If I were back in Washington State or Alaska again I would put a drip cap over my newer Dometic doors if I were stuck side saddle regarding the refrigeration of my trailer.
Look around at the choices, if you have any questions feel free to P.M. me.
Thanks for a great thread.
Happy Camping, Safe Trails.
Harry
Harry,
Sorry to sound lame, but "side saddle refrigerator" is a new term to me. What is that? And do I have it?
I'm guessing Harry is using "side saddle" to refer to a refrigerator/camper that uses side venting instead of the more effective top (roof) vent.
Actually, looking at the louver design of the newer side vents, I'm thinking it might just be better to go to a top vent. If the flue is tightly joined, the only place any water would go is down the pipe (to one specific area at the bottom), and it might be easier to cap than a "huge" side vent.
It looks like some of the Compact family of trailers use a roof vent. I also see them at Vintage Trailer Supply for Airstreams. If anyone reading this thread has used one I'd be interested to hear about it.
Raya
Actually, looking at the louver design of the newer side vents, I'm thinking it might just be better to go to a top vent. If the flue is tightly joined, the only place any water would go is down the pipe (to one specific area at the bottom), and it might be easier to cap than a "huge" side vent.
It looks like some of the Compact family of trailers use a roof vent. I also see them at Vintage Trailer Supply for Airstreams. If anyone reading this thread has used one I'd be interested to hear about it.
Raya
QUOTE (Harry Young @ Oct 19 2009, 09:34 AM)
To All,
On the subject of the Newer Dometic doors in this thread...
I must also in all fairness state that snow will get in them, driving rain is an issue too...
To still use the better door for warm weather operations of a Dometic refrigerator I have had to deal with this issue.
I have installed pop snaps onto the trailer wall and made in the past a vinyl storage cover to snap on for long term stowage.
I have seem pre-made travel covers, but for the life of me I cannot find them now.
You might need to give thought to this issue ahead of time, such as a long wet nasty drive ect.
As a service person I have seen water damage in the rear compartment because of this door designs very open features.
Likewise I have ALSO witnessed the very much improved operation of the refrigeration in side saddle installed refrigeration.
I recommend these doors for that delema...I prefer where possible the old doors and top venting.
This seems the devil one must pay to get the benefits for warm weather operation.
Consideration and planning should mitigate the drawbacks of this door design once its understood.
Happy Camping, Safe Trails.
Harry
On the subject of the Newer Dometic doors in this thread...
I must also in all fairness state that snow will get in them, driving rain is an issue too...
To still use the better door for warm weather operations of a Dometic refrigerator I have had to deal with this issue.
I have installed pop snaps onto the trailer wall and made in the past a vinyl storage cover to snap on for long term stowage.
I have seem pre-made travel covers, but for the life of me I cannot find them now.
You might need to give thought to this issue ahead of time, such as a long wet nasty drive ect.
As a service person I have seen water damage in the rear compartment because of this door designs very open features.
Likewise I have ALSO witnessed the very much improved operation of the refrigeration in side saddle installed refrigeration.
I recommend these doors for that delema...I prefer where possible the old doors and top venting.
This seems the devil one must pay to get the benefits for warm weather operation.
Consideration and planning should mitigate the drawbacks of this door design once its understood.
Happy Camping, Safe Trails.
Harry
Whew! My head is spinning... Harry, can you say, by looking at the set-up I now have, that you recommend replacing the vents (as shown) with those you've referred us to at eBay?
QUOTE (Raya L. @ Oct 19 2009, 11:56 AM)
I'm guessing Harry is using "side saddle" to refer to a refrigerator/camper that uses side venting instead of the more effective top (roof) vent.
Actually, looking at the louver design of the newer side vents, I'm thinking it might just be better to go to a top vent. If the flue is tightly joined, the only place any water would go is down the pipe (to one specific area at the bottom), and it might be easier to cap than a "huge" side vent.
It looks like some of the Compact family of trailers use a roof vent. I also see them at Vintage Trailer Supply for Airstreams. If anyone reading this thread has used one I'd be interested to hear about it.
Raya
Actually, looking at the louver design of the newer side vents, I'm thinking it might just be better to go to a top vent. If the flue is tightly joined, the only place any water would go is down the pipe (to one specific area at the bottom), and it might be easier to cap than a "huge" side vent.
It looks like some of the Compact family of trailers use a roof vent. I also see them at Vintage Trailer Supply for Airstreams. If anyone reading this thread has used one I'd be interested to hear about it.
Raya
Sheesh! You wouldn't think a little 1.9 cuin fridge would create such a, ahem, heated discussion.
As it turns out, I also own a '65 Airstream Globetrotter that I'm restoring, and the fridge top-vented "flue" is as wide as the fridge. Ugly, too. I really don't want to think about adding something so "imposing" into my little Scamp just to accommodate a top vent...
There's got to be an efficient way to make the side venting work appropriately. Dontcha think?
Oh yes, I think side venting can be made to work, as evidenced by Roy in TO's success (similar methods to Harry's).
It's just that you're always trying to "force" the fridge to vent, when a vertical chimney does it with comparative ease. With the new-style -- and clearly more effective -- vents being much less of a "leak resistant" design, well, it made me re-consider roof venting. Not that I'm saying I'll change over for sure; just thinking about it.
The Compact family has a relatively small, tidy-looking rounded vent. Or, I wonder about an openable/closable mushroom ventilator like you'd use on a boat. Hmm, for that matter, what about a solar powered Nicro vent on the roof? They are actually made to be watertight, can be removed and replaced by a screw in deck plate for extreme storms, move a fair bit of air, and are "water proof"* One of those hooked up to a chimney might be a good system.
Click to view attachment
http://www.marinco.com/product/4-daynight-...less-steel-vent
(You can remove the vent and replace it with a threaded, completely watertight cover.)
With one of these up top, I wonder if one could put the air intake vent under the floor, and do away with the huge, somewhat unsightly, vents from the side altogether?
Raya
*I put "water proof" in quotes because while they are basically waterproof under most sailing conditions (and sailing can force water into granite, I swear), I wouldn't take one offshore where it would be constantly submerged though and for boats I've always been a wee bit skeptical of them (because there is a sturdier solution that would be impractical for campers). But for the roof of a camper.... Hmmm, I'm going to think about this.
It's just that you're always trying to "force" the fridge to vent, when a vertical chimney does it with comparative ease. With the new-style -- and clearly more effective -- vents being much less of a "leak resistant" design, well, it made me re-consider roof venting. Not that I'm saying I'll change over for sure; just thinking about it.
The Compact family has a relatively small, tidy-looking rounded vent. Or, I wonder about an openable/closable mushroom ventilator like you'd use on a boat. Hmm, for that matter, what about a solar powered Nicro vent on the roof? They are actually made to be watertight, can be removed and replaced by a screw in deck plate for extreme storms, move a fair bit of air, and are "water proof"* One of those hooked up to a chimney might be a good system.
Click to view attachment
http://www.marinco.com/product/4-daynight-...less-steel-vent
(You can remove the vent and replace it with a threaded, completely watertight cover.)
With one of these up top, I wonder if one could put the air intake vent under the floor, and do away with the huge, somewhat unsightly, vents from the side altogether?
Raya
*I put "water proof" in quotes because while they are basically waterproof under most sailing conditions (and sailing can force water into granite, I swear), I wouldn't take one offshore where it would be constantly submerged though and for boats I've always been a wee bit skeptical of them (because there is a sturdier solution that would be impractical for campers). But for the roof of a camper.... Hmmm, I'm going to think about this.
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