Fridge Performance Survey

[Boler77]

Originally Posted by Boler77

ZachO my friend,

Those darn fridge goblins have palgued so many of us. I have had some luck improving the performance of many of my friend's fridges as well as myself. The original maunal 3-way of the 1977 17' Boler died some time ago, and replace witha full automatic Dometic. Don't remember the model number as it was pure junk and best that it is forgotten. This one had a control board and no settings for setting the fridge colder. This one was to anticipate heating up and cool down. To keep this short, this fridge couldn't anticipate sh*t. Removed it after a week. The replacement for my old manual Dometic was the RM2354. Because of the warranty it had to be installed by a factory recognized RV dealership. Well it was insrallled and at best I was getting temps the same as you. I was not happy.

One thing I have learned is to have patience, and alot of it. I ordered my supply of patience off Amazon. Anyways any changes made to the performance of the fridge may or may not make the performance better. One thing I have noticed in about the last 10 fridges that I have helped friends is that nothing in these trailers is really level. The importance of having a level fridge is an absolute must. The front to back of the trailer or in the case of the fridge because it is sideways mounted (side to side) level is very important. The front to back of the fridge is slightly less, but I try to get the both bang on.

My first approach is to level the fridge front and back and compare this to the level of front to back and side to side of the trailer. There must be a trailer out there somewhere that the fridge is leveled to the frame. But I have not found one yet. I will say Casita comes so close though. So I first now level the trailer front to back and side to side, with the four jacks. I usually use a 4 foot level. Maybe over kill butI am only doing this once. Then after that I take a a 9 inch torpedo level and compare ti the fridge. Most of the time the side to side leveling of the fridge is not usually to far out from the trailer being level. The fronto back is usually way off. Like the bubble is pasted to one end. More times than not the back of the fridge needs to be lifted. I usually emove the fridge and insulate the fridge with a few layers of Reflectix. If the waals cavities of the fridge compartment have been framed out and there are pockets, the I use 2 sided tape and place a minimum of one layer of Reflectix, two if possible. If there is a heater or cupboard space under the fridge I will try my best to install several layers of Reflectix. If there is a cupboard above the fridge the the underneath portion of the cupboard gets a layer or 2. The base of the fridge bay gets 2 layers. The reason for using Refectix is that I find it easier to fit better than the pink. Each to ther own though. Some fridge doors allow a layer in between the outer trip wood panel and the inside, some not. If this is an older fridge, I have already checked for amonia leaks and cleaned the dust off the tubes and upper fins. Now check the chimney tube. I found to many fridges at the spiral ribbon that is fitted down the chimney tube either missing or off the wire. The spiral ribbon is very important in causing the flue gases to spiral. I won't get into all of that science here. Not sure why the spiral ribbons are missing, but putting them back on the wire holder is simple enough. Having a clean chimney is important. The last fridge fridge I looked at this last week at the beginnings of a wasp nest, no less than 50 black flies and a few dead spiders. I guess they all like the smell of propane .

After the fridge and compartment has been properly insulated, then I use shims under the metal runners that the fridge sits on. These metal runners run from the front of the fridge to the back. There is usually a few holes to attach them to the deck of the fridge compartment. The reason of leveling the fridge to the trailer, is that I am just plain tired of everything out of kilter. This way if the trailer is level, so should be the fridge, but I usually given it a quick check to be sure. Each glass trailer is different as to the amount of shim under the metal runners. Usually 1/4 to 3/4 inch. I guess this depends on who installed the cabinetry. So now the fridge is level to the trailer and insulated.

Now Dometic asks for a 1 inch gap from the tubes at the back of the fridge to the outer wall of the trailer. Please find me a trailer that has the 1 inch gap. No fintage glass trailer yet that I have seen.

I usually use a very thin panel board that id flexible and light to work with and very thin and easy to cut galvanized sheet metal (Home Depot). What I usually do it cut the galvanized sheet so that I am able to seperate the chimney from the cooling tubes. So this piece runs vertical up between.and goes from just below the 120 volt electrodes to the top of the cabinetry above the fridge. You will have to cut a small slot fro one of the tubes to pass through. A small pit of reflective tape to hold it in place against the back of the fridge. The purpose of this is to keep the hot flue gases away from the the top cooling fins at the top of the back of the fridge. This vertical sheet metal piece then forms the corner to the paneling that I use that is 1 inch away from the tubing running vertical from about 5 to 6 iches from the bottom of the fridge base to just even with the top of the cooling fins at the top of the fridge. This panel is just attached to the wall of the cabinet with small metal L brackets and screws. I use refective tape on the back of the paneling and run a strip a flective tape down the seam of the corner of the metal and panel corner where they meet. So now the chimney air and the air form the cooling fins are seperated. The last piece to install is where I install a piece of panel board that is fitted just slightly above the top edge of the lower vent and runs straight across the wideth of the fridge cabinet, This will vary in length and depth depending on the trailer and fridge depth in the cabinet. This piece can run flat or at an slight angle. This piece was attched to the walls of the cabinet with small L brakets and the other edge butts against the vertical panel that is 1 inch from the tubes. This will close off this area and force the air to go up the bottom of the vertical panel and as the air rises it must pass through the cooling fins, and the air is also allow to go another route and up along the chimney and and out. The exhaust air from each will not mix until it goes out the outer vent holes. Now to help with the air movement to the outside I first installed a heavy duty 4 inch fan and placed it at an angle and pushed the air up from the bottom. The fridge would not cool properly, so Because the upper and lower fridge vents each have three opening, I installed three 4 inch computer fans inside each of the upper vent openings and blew the air out. Wow a big success. Not sure the cubic feet of air that each move, but yo can definitely feel the warm air from the cooling fins from the two vents and the much hotter air from the exhaust of the chimney. Can you have too much ventilation. I would think on the cooling fin side not so much a problem,but on the chimney side, all I want to do is get rid of some of the heat, so that it does not collect inside, but not too much air movement as to disrupt the chimney flue gases. If that is possble. I would think that when going down the highway and you are on propane, there must be alot of air movement. Well it worked.
The three fans pull 0.4 amps/hr. I can live with that.I have 3/4 of kilowatt of solar so not really a problem and it would be several days boondocking before that would put any strain on a good set of deep cycle batteries.

One of the things that I noticed is that on some fridges there is no plug on the drain hose coming from the back of the fridge for the drip tray. If the hose is left open, warm air will creep up and into the fridge. Some caps have from one small hole to several very tiny holes drilled in the cap to let the water out. A little more difficult for the warm air to go up into.

The fan in the fridge blowing from the bottom or against the inside cooling fins worked on some of the fridges, about half it heped, on the RM2354 it did not. In fact it messed up the inner cooling effect alot. But for some it works, not sure why.

I thing some fans give off more heat than they do help in circulating the air. I did try the small Coleman fan withe the D cell batteries, t seem to work. That fan unit did not heat up the interior of the fridge, did it help not sure.

Probably and more importantly was the fact that the fridge must have something inside it for the cold air to be absorbed into whether it is water bottles or beer. An empty fridge is diificult to gauge. I have had this one trailer in the upper 90 degrees F and 100 % humidy and the unit will stay at 33.5 to 34.5 on a setting of 3 out of 5. I am happy with that.

Is each situation differnt, very much so. Ya got to have time to play with things, make slight changes and wait and be patient to see if the changes have any effect.

As for the warm exhaust air being recirculated we used a large smoke emitter and when there was no breeze outside we estimated that at least 50% of that exhaust air was being recirculated and this was done on several of the trailers we worked on. How often is there no breeze , not often, but to solve it we just put a temporary deflector as to deflect that hot exhaust air when no breeze occurs. I never thought this would have happened until we were seeing how much warm air was was being forced out the top vents.

Well the fridge works great now

[ZachO]

Thanks Greg! That's a lot of good info. I'll check the level (how do you measure front to back level with the fridge installed? From inside the fridge?), and think again about that vertical baffle. I have a couple computer fans I plan to install just under the upper fins. I guess these will be the last things I do before giving up!

[Boler77]

Hi ZachO

Well I used the belly band as a reference point to start my leveling. These trailer are like boat building. Nothing is square or level. From there I started placing a 2 foot level on the countertops. I even checked the sleeping area, top bunk was level with the trailer. So if the sleeping area is all level I am ok with that. I can live if my countertop is off a bit Not bad, not perfect either. But close enough. Why level the trailer people have asked. My answer is if you can find a good place to level the trailer and use that mark to reference your fridge to, then you don’t need to open the fridge for level placement. As I face my fridge in my trailer, like most trailers, it would be the side to side of the fridge I am checking in comparison to the front to back of the trailer. I place the level in many spot of the fridge to compare. Nothing says the floor of the fridge is correct but I the n place I the level under the freezer or in the freezer compartment. Who says that the cubby where the fridge is placed is even level to the trailer. Once I know the fridge what the side to side of the fridge is doing. Then I checked the front to back of the fridge ( side to side of the trailer). There are usually metal runners under the back of the fridge to attach it to the deck. I placed wooden shims under the runners until the fridge was level.

I think what helped me the most was , separating the exhaust flue gases away from the top cooling fins. What still amazes me is that original manual fridge worked flawlessly without modification and I have friends that still have the originals and work perfectly. Many people have mentioned here and other forums that the flue exhaust temp while on propane runs around 500 to 550 F. How are the cooling fins to cool if there is that kind of heat passing by and mixing with the cooler air. So by placing a vertical metal sheet baffle and entirely closing it off, I feel this was a big factor. I have taken fridges that people say won’t work in their trailers, place them in my garage, connect them to propane, and they work fine. In fact flawlessly. Air circulation I think is the biggest factor. When the fridge is in the counter space, airflow is so restricted. By talking to Dometic and working and following their recommendations and by installing the false wall 1 inch from the tubing at the back of the fridge results in the a chimney affect and forces the air to be pulled in near the bottom and up through the coils and through the top fins. I never tried putting a fan mud way up, like the Casita factory or Dometic has done, otherwise I can not maintain that 1 inch spacing. Levelling is a big factor and air circulation. Why the old manual fridges worked so well remains a true mystery. What I have noticed is that the older fridges in most cases had greater depth and sat further back in the compartment, so possibly this helped with the airflow using the side of the trailer as the wall. I did try the fan from the bottom blowing up and the fridge refused to cool. So with the three fans on each of the three upper vents, it works. High 90f yesterday 100 % humidity and the fridge sat at 34 to 36 F on a setting of 4 out of 5. The freezer was -12 F. At night if it cools off I turn the fridge to a setting of 2 or 3 or everything will freeze.

The other factors are the vents used today are different than the old style.

When you get everything all connected up. The vertical metal shield and the fans in place. Place you hand near the top of the lower vents and see how much really warm air is coming down from the upper vents.

Anyways I hope this helps

[Boler77]

Originally Posted by ZachO

Thanks Greg! That's a lot of good info. I'll check the level (how do you measure front to back level with the fridge installed? From inside the fridge?), and think again about that vertical baffle. I have a couple computer fans I plan to install just under the upper fins. I guess these will be the last things I do before giving up!

ZachO

Never give up. One last question. Do you have 11 cm of water column gas pressure at the fridge? If so then this is only an air problem. The fridge is trying to expel the heat from the cooling process and between the flue gases and cooling fins heat, circulation is restricted.
What I have also noticed is because of the difference maes of glass trailers and how they are set up fridge wise, each situation is different and what works on one doesn't always work on another, and why some of us have fridge problems and others do not, well tht is a lottery question at best.

[Boler77]

Originally Posted by Boler77

ZachO

Never give up. One last question. Do you have 11 cm of water column gas pressure at the fridge? If so then this is only an air problem. The fridge is trying to expel the heat from the cooling process and between the flue gases and cooling fins heat, circulation is restricted.

That is the same as 0.4 lbs per square inch, I would try everything before I would junk the fridge, even take it out and see if it will run outside of the trailer. I have found that almost every fridge that people want to scrap, works great out of the trailer unless there are controll issues or ammonia leaks. Most of the time it is gas pressure and venting.

[ZachO]

The fact that I have to build a manometer in order to test the pressure is the reason why, after over a year of struggling with this thing, I still haven't tested the pressure.

I will eventually...

Just to recap, since I don't expect you to read this whole thread, I have:

-installed a fan in the center of the upper vent, blowing hot air out
-installed a curved metal sheet in the top of the upper compartment to move air out
-installed two metal baffles, one right below the upper fins, one down lower, with less than 1" air gap between them and the fins
-stuffed as much fiberglass insulation as I could around the sides of the fridge (no room on the top side)
-fan inside fridge
-new propane regulator
-cleaned chimney, orifice and burner tube
-extended the chimney up above the cooling fins

I still plan to build a vertical baffle to more less totally separate the chimney/burner heat from the fins, check the gas pressure and someday build a bracket so I can install the two computer fans I bought, right below the upper fins to blow air on them, and possibly buy a new upper vent cover which allows better flow.

[tractors1]

Originally Posted by ZachO

I still plan to build a vertical baffle to more less totally separate the chimney/burner heat from the fins, check the gas pressure and someday build a bracket so I can install the two computer fans I bought, right below the upper fins to blow air on them, and possibly buy a new upper vent cover which allows better flow.

If you have a roof top vent and you're going to remove it one last thing you might want to try is to cut a piece of flexible dryer duct (metal, not the plastic stuff) and work it over the top of your burner tube extending up to the bottom of the vent screen. I used wire to secure the top to the metal screen in the bottom of the vent, so the hot gases have no place to go but straight up. Worked superb, eliminated the need for my fans around the coils.

[ZachO]

Thanks Charlie.

I think if mine were top-vent, I wouldn't be having these problems.

[Burro1]

Using propane is an old fashioned and inefficient way to run a refrigerator.

Solar is relatively cheap today. We run our 12 volt 5.8 cu ft NovaKool with 210 watts of solar. Just returned from a month in the southwest. Hottest day was a sweltering 117 deg. Fridge worked normally.

[ZachO]

I appreciate the input, and don't disagree. However the idea of "doing what's most efficient" assumes money is no object. But of course it is.

Oversimplified but fairly accurate math:

Convert to electric fridge powered by solar:

Fridge: $1,300
Solar including connections, mounting etc: $800
Battery System: $2-300
Plus any miscellaneous expenses, we're looking at well over $2,000.

Fix my propane fridge, which, though you can call propane inefficient, can run a fridge on a match-size flame for a month with a 20# propane tank that costs under $20 to fill:

Supplies: Maybe $100 for fans, aluminum sheet metal, adhesives.
Time: A lot of it, but my time is my time and I spend it how I like. Though I don't much prefer spending my time on a fridge, I have more time than money.

A 12V fridge and the solar to support it just isn't in the cards.

[Burro1]

Looks like you already spent a bunch of time and money trying to make the propane fridge work

[k corbin]

Cost effective means you could buy some block ice to put in a container in the fridge for the few weeks of the year you can't keep the fridge cool enough.

If you can't fix it with engineering and money then be flexible in your solutions and your attitude about the issue. Meaning remind yourself it only happens for a short period of time and the rest of the time it does not need to be fixed.

[Burro1]

I futzed around with Propane refrigerators for 20 + years and finally went for it

Good luck Zach

[ZachO]

Both good points.

Rob, yes, I mean you only have to look at the length of this thread, and the various other fridge threads on the site to see that for some, it's a major pain. Others have very few problems. But obviously these things need the right conditions to work well, and the RV manufacturers often don't set them up for success...

And yeah Karin, I was just thinking about that this morning. It's really only July and August that this is a problem. I mostly manage to limp it through those months. But it seems possible to get another 5 or 10 degrees out of this thing, and that's all I'd need.

If money were no issue, there's a lot of things I'd do to my trailer, and an electric fridge and solar array would definitely be one of them. But it can't happen any time soon, so here I am, working with what I've got.

Thanks.

[Boler77]

Originally Posted by ZachO

Both good points.

Rob, yes, I mean you only have to look at the length of this thread, and the various other fridge threads on the site to see that for some, it's a major pain. Others have very few problems. But obviously these things need the right conditions to work well, and the RV manufacturers often don't set them up for success...

And yeah Karin, I was just thinking about that this morning. It's really only July and August that this is a problem. I mostly manage to limp it through those months. But it seems possible to get another 5 or 10 degrees out of this thing, and that's all I'd need.

If money were no issue, there's a lot of things I'd do to my trailer, and an electric fridge and solar array would definitely be one of them. But it can't happen any time soon, so here I am, working with what I've got.

Thanks.

Zach0

and all of the above being said is very relavant. I myself have a lot of time on my hands and rving full-time gives me the time to think about inprovements as well. I enjoyed the challenge that my fridge gave me to make it work more challenging. I have well over half a kilo of solar available and yes I could have gone to a Noval Kool fridge or infact even a bar syslr 110 fridge, but the challenge is what I wanted, and if all else failed, well the other two options were always there and maybe even in the not so far off future one of those options may play out. Solar gives me the opportunity to do and camp where I want. In northern Canada in some of the remote spots, you use either propane or solar, as there is no electrical and in alot of cases the restrictions on generator use really limits any use. I hope that it all works out for you, and if I am able to assist feel free to contact.

enjoy

[ZachO]

Thanks Greg. In the summer I fulltime in my camper. But I'm not retired...so these things matter but I don't have quite the time I'd like to work on them. I like the challenge but mostly wish this fridge would just work, after all the time I've already put into it.

I've got your suggestions and my now relatively short to-do list for my fridge. Right now I'm working during the week and even though the smoke has moved in, it's still prime get-out-in-the-mountains weather, so most weekends I'll be backpacking or floating. But I'll do what I can for the fridge and worst case, I get to this stuff in September, and possibly have to wait till next summer to see what worked and what didn't.

Thanks for all the help and I'll keep you updated.

[k corbin]

Hopefully by next summer you can add some solar. Your pricing on the cost of solar is what the cost was 5 years ago. Now you can get a 100 watt panel kit with wiring, brackets and controller from Renogy for $184.00 with free shipping and sometimes even less when they run a special deal on them on Amazon.

The 12v portable chest fridge/freezers are much more efficient units than the fridges with a side opening door. There is a new brand on Amazon that is reasonably priced but getting good reviews from Van dwellers. https://www.amazon.com/Alpicool-C20-...70_&dpSrc=srch

But the other thing about the 12v portables is the used ones in good working condition show up a lot more often than a used built in fridge/freezer on any type of fuel source. Seattle craigslist gets one or two a month listed, they come out of boats including some of the smaller sized front door models.

I lucked out and was given a 50 liter Waeco portable last week. It is larger than I want but I managed to fit it into my build plan. I had to make the bed an inch narrower and since I had not yet built the framing for the bed that was an easy modification. I would prefer to have gotten a smaller unit to put in a pull out tray in the cabinet...maybe someday I will get that done but not soon unless I trade down with someone who is wanting to trade up to a larger fridge.

Approach the change over in stages, it does not have to all happen at once.

Mine has been done over 18 months for this stuff. I got the solar panels last year, then a few months ago I came across a below cost deal on a 160ah AGM battery, then the fridge which was free otherwise I would not have been able to buy it until November. Now I just need to buy the cable clam fitting for the roof and some cables. I still need to fabricate some mounting brackets for the panel out of some aluminum angle I have on hand. Putting the panel on the roof is on hold until my friend recovers from a recent surgery and then catches up on the work he missed from that. Two person job, I need a helper.

[ZachO]

Nice. Yeah that model is affordable. Cool thing about your situation is that you can build to suit. I'd have to modify a lot to fit that in my camper, but it would be doable. Maybe even under one of the dinette seats where no one sits.

We'll see. For now I'm working with what I have. I have 90W of solar already. I don't monitor my battery all that accurately, I just use the built in display panel. Charge, good, fair and weak. Mine mostly stays in "good", but will dip into fair regularly this time of year when my fridge exhaust fan is running constantly, and again in early spring, late fall when I run the heater all night. So I would say my 90w and one battery is adequate for my current use, but wouldn't support much more. I tend to charge all my electronics at work, too, so my 12V use is pretty minimal outside the constant fridge fan.

[k corbin]

Originally Posted by ZachO

Nice. Yeah that model is affordable. Cool thing about your situation is that you can build to suit. I'd have to modify a lot to fit that in my camper, but it would be doable. Maybe even under one of the dinette seats where no one sits.

We'll see. For now I'm working with what I have. I have 90W of solar already. I don't monitor my battery all that accurately, I just use the built in display panel. Charge, good, fair and weak. Mine mostly stays in "good", but will dip into fair regularly this time of year when my fridge exhaust fan is running constantly, and again in early spring, late fall when I run the heater all night. So I would say my 90w and one battery is adequate for my current use, but wouldn't support much more. I tend to charge all my electronics at work, too, so my 12V use is pretty minimal outside the constant fridge fan.

That portable fridge could very well be about the same use of power as the fridge fan especially if you add extra insulation around the portable fridge. But then again you probably on run the fridge fan in the hotter months.



Eventually I will have a smaller portable fridge on a pull out tray located in a cabinet. The big free fridge is too much of a space hog but it will do for now since there are still essential expenses to go on my project. Safety comes before creature comforts.

[Dave Fish]

Originally Posted by k corbin

Hopefully by next summer you can add some solar. Your pricing on the cost of solar is what the cost was 5 years ago. Now you can get a 100 watt panel kit with wiring, brackets and controller from Renogy for $184.00 with free shipping and sometimes even less when they run a special deal on them on Amazon.

The 12v portable chest fridge/freezers are much more efficient units than the fridges with a side opening door. There is a new brand on Amazon that is reasonably priced but getting good reviews from Van dwellers. https://www.amazon.com/Alpicool-C20-...70_&dpSrc=srch

But the other thing about the 12v portables is the used ones in good working condition show up a lot more often than a used built in fridge/freezer on any type of fuel source. Seattle craigslist gets one or two a month listed, they come out of boats including some of the smaller sized front door models.

I lucked out and was given a 50 liter Waeco portable last week. It is larger than I want but I managed to fit it into my build plan. I had to make the bed an inch narrower and since I had not yet built the framing for the bed that was an easy modification. I would prefer to have gotten a smaller unit to put in a pull out tray in the cabinet...maybe someday I will get that done but not soon unless I trade down with someone who is wanting to trade up to a larger fridge.

Approach the change over in stages, it does not have to all happen at once.

Mine has been done over 18 months for this stuff. I got the solar panels last year, then a few months ago I came across a below cost deal on a 160ah AGM battery, then the fridge which was free otherwise I would not have been able to buy it until November. Now I just need to buy the cable clam fitting for the roof and some cables. I still need to fabricate some mounting brackets for the panel out of some aluminum angle I have on hand. Putting the panel on the roof is on hold until my friend recovers from a recent surgery and then catches up on the work he missed from that. Two person job, I need a helper.

I just bought one of these except mine has the lithium battery that is supposed to last up to 10 hours without outside power. It also comes with the solar connection for boondocking. I literally just got it last night and am testing it today.

After a full charge, it showed 12.5 volts. After 2.5 hours maintaing at 39 degrees, it's showing 11.9 volts at 41 degrees. It looks like it warms up a little between cooling cycles, which should be considered when setting the desired temperature. I currently have it set on eco mode and it's in the dining room, so the room temperature is not extreme.

I will be interested to see if the 45w solar panel on the Campster can keep up with it. Speaking of Campster Karin, I'm not sure we will leave it inside when we are camping. It might be awkward squeezing around it in the isle. There are 2 of us and a 83 pound German Shepherd.we have a pop up tent that we can use to protect it from the elements.

Other observations: it's fairly heavy but has good molded handles as well as the wheels. The food storage area extends under the cooling unit, which surprised me but is neither good or bad. It makes kind of a gurgling noise when it is running, but that is normal according to the book.

We have a trip planned in a couple of weeks, so I'll do an update when we return.