Vented cat heater - Page 2 - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-22-2011, 11:14 AM   #15
Senior Member
 
DannyH's Avatar
 
Name: Dan
Trailer: 1976 Scamp 13 ft "Siesta"
Oregon
Posts: 546
Registry
Andy, I mainly got this because I had limited space, and with the remodel couldn't figure out where to put a conventional heater. The one thing that the Cat has, at least from reading about it, is that it is over 95% efficient at using the gas for heating. I believe this is much more than the conventional heater, so it should make your propane last longer. I'm also a light sleeper and have heard that the fan noise is loud on a regular heater. I have tested mine out and I can barely hear it. I think if I had the space and a larger trailer I would think of putting in a regular heater, but this unit worked out well for my situation.
__________________

__________________
DannyH is offline   Reply With Quote
Old 04-22-2011, 08:02 PM   #16
Senior Member
 
Trailer: 1980 Burro
Posts: 288
Quote:
Originally Posted by DannyH View Post
Andy, I mainly got this because I had limited space, and with the remodel couldn't figure out where to put a conventional heater. The one thing that the Cat has, at least from reading about it, is that it is over 95% efficient at using the gas for heating. I believe this is much more than the conventional heater, so it should make your propane last longer. I'm also a light sleeper and have heard that the fan noise is loud on a regular heater. I have tested mine out and I can barely hear it. I think if I had the space and a larger trailer I would think of putting in a regular heater, but this unit worked out well for my situation.
That is the best reason of all, you installed the one that fits.
__________________

__________________
Andy B is offline   Reply With Quote
Old 04-23-2011, 01:23 PM   #17
Senior Member
 
Mike Magee's Avatar
 
Name: Michael
Trailer: Li'l Hauley
Oklahoma
Posts: 5,145
Quote:
Originally Posted by Andy B View Post
What is the advantage of this heater over a conventional heater like the Atwood 8012? People usually choose a cat heater because it does not use any electric power, but this one uses 5 amps for 2 min each time it starts and then 0.5 amps after that when running. The 8012 uses 1.8 amps when running. The 8012 puts out a lot more btu's so it would not run nearly as long on each cycle and it has a blower to move the heated air around inside the trailer. The cat requires opening a window for fresh air or a leaky trailer, which is not good when you are trying to heat the inside space. The 8012 has a fresh air source built into the exhaust system. The 8012 also costs less and does not take as long to get when ordered and spare parts are available from lots of places. The cat is a different shape and a little smaller, but I don't see an advantage over a conventional furnace like the 8012 since it seems like it will draw more electric power.
2 minutes is negligible, so we can almost forget about the 5 amp draw for that short a time. Figuring .5A per hour, if there's 40A available for use in the battery, that would run the heater theoretically for close to 80 hours straight. But I would think the plat cat would shut off for periods of time when it got warm enough.

When I had a conventional rv furnace (in a 22' Rockwood, about 5 years ago) I recall one time boondocking in Colorado when it got into the 40s for a couple nights. The furnace did the job (albeit noisily) the first night. Then I drove about 20 minutes up the highway and found a new spot, and the second night it operated once and then ran out of juice (middle of night, blower running but no heat! Yuck!). So to my way of thinking, the cat should heat much longer than 2 nights.

Part of it may be that the furnace fan must run for a while before the burner kicks in, then it runs while the burner operates, then it keeps running for several minutes after the burner is done... blowing cold air! All of that runtime uses battery juice.

It seems like it would be possible to run a fresh air line from outside to the plat cat, if someone were handy. (that leaves me out!)

The trailer I just bought has one of those noisy furnaces. I almost special ordered one just to delete the furnace! In the end I took what was on the lot. I'll probably use the furnace occasionally to quickly bring a cold trailer up to comfy temp, then switch to the Coleman Black Cat (with windows cracked) to maintain temp. The latter is silent, great for sleeping.
__________________
How much time do we have left? 2 Chr. 7:14
Mike Magee is offline   Reply With Quote
Old 04-23-2011, 05:05 PM   #18
Senior Member
 
Francesca Knowles's Avatar
 
Name: Francesca Knowles
Trailer: '78 Trillium 4500
Jefferson County, Washington State, U.S.A.
Posts: 4,543
Registry

Name:   Cat-htr-4b-796552.jpg
Views: 117
Size:  20.1 KB
The "Plat Cat" heater (pictured) came up in a thread I started about condensation problems I had that were partly related to my use of a standard propane catalytic heater.
I think it's wrong to refer to this as a "fully vented" heater, especially if one presumes "vented" to mean that combustion byproducts (mainly water and carbon DIoxide) are vented to the outside. As you can see in the picture, the whole combustion surface is exposed to the interior of the trailer, meaning that warm, rising, vapor-laden air enters the trailer immediately, bypassing the "power vent". It's my opinion that the ONLY working difference between this and standard propane catalytics is that the fan may draw additional oxygen IN to the trailer, thus somewhat allaying the main safety concern attached to their use : oxygen depletion.
Even this advantage may be in doubt, since the manufacturer apparently directs the user to open a window somewhere in the trailer.
If it's true as posted earlier in this thread that this heater doesn't have a U.L. approved listing, it may be due to the dubious nature of the claims made by the manufacturer.


Francesca
__________________
Francesca Knowles is offline   Reply With Quote
Old 04-23-2011, 08:39 PM   #19
Senior Member
 
Mike Magee's Avatar
 
Name: Michael
Trailer: Li'l Hauley
Oklahoma
Posts: 5,145
Francesca, those are some very interesting observations and you have raised some questions in my mind. I just sent off an email to the manufacturer, asking for clarification on the venting's thoroughness (or lack thereof) and the air intake issue. I'll report back when I receive an answer.
__________________
How much time do we have left? 2 Chr. 7:14
Mike Magee is offline   Reply With Quote
Old 04-23-2011, 09:47 PM   #20
Senior Member
 
Francesca Knowles's Avatar
 
Name: Francesca Knowles
Trailer: '78 Trillium 4500
Jefferson County, Washington State, U.S.A.
Posts: 4,543
Registry
Quote:
Originally Posted by Mike Magee View Post
Francesca, those are some very interesting observations and you have raised some questions in my mind. I just sent off an email to the manufacturer, asking for clarification on the venting's thoroughness (or lack thereof) and the air intake issue. I'll report back when I receive an answer.
I'll be interested in their reply, and especially in any independent studies they may cite that support their claims...

.....
Francesca
__________________
Francesca Knowles is offline   Reply With Quote
Old 04-23-2011, 10:10 PM   #21
Senior Member
 
Trailer: 1980 Burro
Posts: 288
Quote:
Originally Posted by Mike Magee View Post
2 minutes is negligible, so we can almost forget about the 5 amp draw for that short a time. Figuring .5A per hour, if there's 40A available for use in the battery, that would run the heater theoretically for close to 80 hours straight. But I would think the plat cat would shut off for periods of time when it got warm enough.
2 minutes at 5 amps uses the same amount of power as .5 amps for 20 minutes. If the duty cycle is 10 min on then 10 min off and repeat the startup part of the cycle uses more power than the running part of the cycle. The longer the on/off cycle the less important the start up draw is. The off part of the cycle depends on how quickly the trailer looses heat, not the type of heater. Since the cat heater does not put out a high btu level, maybe it runs for long periods of time or even continuously.
__________________
Andy B is offline   Reply With Quote
Old 04-24-2011, 10:02 AM   #22
Senior Member
 
Name: Darwin
Trailer: 2002 19 ft Scamp 19 ft 5th Wheel
Posts: 3,030
Send a message via Yahoo to Darwin Maring
Years ago we had a gravity heater in a camper and I wish they still sold these heaters because they were ideal for small campers. Vented fresh air and vented exhaust and no noise or electric used.

I rented a Uhaul type of egg back about 22 years ago and think it had one too.
__________________
Darwin Maring is offline   Reply With Quote
Old 04-29-2011, 07:15 PM   #23
Senior Member
 
Mike Magee's Avatar
 
Name: Michael
Trailer: Li'l Hauley
Oklahoma
Posts: 5,145
Quote:
Originally Posted by Francesca Knowles View Post
I'll be interested in their reply, and especially in any independent studies they may cite that support their claims...

.....
Francesca
I received a reply. They indicated that the design has been certified by the National Gas Association, that it does collect the combustion gases and vent them. The plenum at the top sucks the gases up and out. It sucks about double the volume needed to gather the byproducts, which would have the added effect of creating a change of air in the trailer every so often.

For air intake, they say an intake inlet can be rigged if desired; 1.5" is plenty big. Actually an opening of about 8 or 9 mm diameter lets in enough air, apparently, so mere leaky window seals might do the trick. I would have had no trouble with air coming into my Burro... besides the old windows, the side vent behind the A/C was wide open and the air could leak quite readily around the A/C and fridge.

If the vent gets blocked or the fan quits working or combustion isn't right, the unit shuts itself down. Seems like a good safety feature.
__________________
How much time do we have left? 2 Chr. 7:14
Mike Magee is offline   Reply With Quote
Old 04-29-2011, 09:02 PM   #24
Senior Member
 
Name: Terry
Trailer: 1996 Casita Freedom Deluxe 17 ft
Colorado
Posts: 392
Quote:
Originally Posted by Mike Magee View Post
I received a reply. They indicated that the design has been certified by the National Gas Association...
I think I'd like a bit more information about this organization since I was unable to Google it up. There are a number of trade groups with names similar to this (such as the National Propane Gas Association) but those organizations seem to be more interested in pushing the use of gas than in certifying heaters.
__________________
Terry G is offline   Reply With Quote
Old 04-29-2011, 09:29 PM   #25
Senior Member
 
Francesca Knowles's Avatar
 
Name: Francesca Knowles
Trailer: '78 Trillium 4500
Jefferson County, Washington State, U.S.A.
Posts: 4,543
Registry
Thanks for getting back, Mike

I'm thinking the same thing as Terry- I wonder what the gas association certification means- I suspect it's more about safe construction than performance claims. I wonder if Consumer Reports has anything?
They told you it the "sucks the gases up and out" ?
I don't get it- are they saying that the heat stays in the trailer, and the water and CO2 go out the vent?
And that no byproducts enter the interior?
That fan would have to suck pretty hard to do that, not to mention be supplied with some kind of magical heat separating device.
I'm still skeptical. I just don't see how it's possible to get rid of all the byproducts without a very substantial amount of heat loss. It's all coming off that exposed combustion surface, and if the fan's moving enough air to vent all the vapor, a lot of heat has to be going out with them.
I'm actually doing much the same thing they're doing with my Eco- Fan setup, and it didn't cost me an arm and a leg to do it. And I'm keeping most of my heat. It's absolutely silent too, which reminds me- if noise is a consideration I'd expect this fan to make just as much of it as any heater fan. It'd be nice if you could hear one work, preferably in a quiet place.
No advantage I can see with the safety features- all cats have low-oxygen shutoffs, and all trailer heaters with fans have low battery shutoffs. Interesting that they claim that a blocked vent will shut off the heater. Is that another switch besides the low oxygen shutoff ?

Francesca
__________________
Francesca Knowles is offline   Reply With Quote
Old 04-30-2011, 12:07 AM   #26
Senior Member
 
Francesca Knowles's Avatar
 
Name: Francesca Knowles
Trailer: '78 Trillium 4500
Jefferson County, Washington State, U.S.A.
Posts: 4,543
Registry
FYI:
Here're some pics of my Catalytic heater/Ecofan combo.
The stone silent fan generates its own electricity using the heat off the heater and circulates about 100 cfpm.
Click image for larger version

Name:	<a title=Trillium Heater 001.jpg Views: 11 Size: 202.1 KB ID: 35517" style="margin: 2px" />......................Click image for larger version

Name:	<a title=Trillium Heater 002.jpg Views: 12 Size: 296.3 KB ID: 35518" style="margin: 2px" />
The two screened cutouts behind the fan are ducted to the outside and supply continuous outside air. I've used this system for four or five years and the only problem I've had has been condensation on the inside walls, though lately I've figured out a better combination of cracked windows, succeeding in expelling more water while keeping more heat.

Ecofan costs begin at $100.00
The pictured RV heater I got brand spankin' still in the box new for $35.00, and I hope it never quits on me-
it'll KILL me to pay full retail for a new one....
The aluminum surround is an old chalk board tray,
and YES, the "hood" is an artistically butchered angel food cake pan!
__________________
Francesca Knowles is offline   Reply With Quote
Old 04-30-2011, 02:28 AM   #27
Senior Member
 
Roger C H's Avatar
 
Name: Roger
Trailer: 2009 Trillium 1300 "Homelet"/2014 Subaru Outback "Rosie"
Washington
Posts: 2,172
Registry
Cool Suffocate or drown, your choice.

Shudder. I wouldn't be able to sleep at night worrying about being asphyxiated.

Plus there is the problem of the added moisture being added to the trailer. There is a discussion on here someplace about that. Fuels yield about a 1:1 ratio on fuel to H2O, that is, burn a gallon of fuel and you get a gallon of water. With no flue, that water goes into the trailer.
__________________
A charter member of the Buffalo Plaid Brigade!

Whether you think you can or think you can't, you're right.
Roger C H is offline   Reply With Quote
Old 04-30-2011, 09:26 AM   #28
Senior Member
 
Trailer: 1980 Burro
Posts: 288
There seems to be 3 reasons why people choose a cat heater over a more conventional furnace like an Atwood 8012. I compare to the 8012 because it is a state of the art conventional furnace with low electric power consumption, low noise, light weight, small size and good efficiency.

1) Reduced electric power consumption/reduced noise because there is no fan.
2) Increased efficiency (less propane used)
3) Different size and shape that will fit where another furnace might not fit.

Comments:

1) The vented cat heater being discussed here has a fan and it is not clear that it uses less electric power or is less noisy than a conventional furnace. It may actually use more power because of the high start up current requirement. It is also not clear how well it actually vents. If it does vent well, there will be no additional water vapor added to the trailer environment and the efficiency will be lower than the non-vented cats. If a non-vented cat is used there is no electric power consumption, however significant amounts of water, etc is added to a very small room requiring open windows or vents to supply fresh air and remove the combustion byproducts.

2) The increased efficiency that is quoted for cats is mostly because they are not vented. A conventional furnace exhausts the combustion byproducts outside the trailer along with some amount of heat. This heat loss is a major reason why the conventional furnace efficiency is lower than a cat. The higher cat efficiency rating is mostly due to the lack of venting because all the heat ends up inside the trailer. Virtually all cat makers say that venting of the heated space is required, however they do not include the loss of heat from this venting in their efficiency calculation because it is not part of their hardware and they have no control how much venting is done by the user. The high efficiency ratings that they quote are misleading due to this. Exhausting combustion byproducts into a living space where they mix with the heated air and then trying to vent only the byproducts through a window or vent while keeping the heat can never work very well unless something like an air to air heat exchanger is used. An air to air heat exchanger for room temperature air would be bulky and not fit very well in a small trailer. Some states have laws against using non-vented heaters in living spaces because relying on the user to properly vent has shown to be unreliable and has sometimes caused death. The 8012 vents the exhaust outside while drawing fresh air for combustion in and transfers some of the exhaust heat to the intake air by using a co-axial exhaust/intake increasing efficiency and effectively isolating the trailer environmental air from the combustion process.

3) Most cats are surface mount and they take away living space both for the cat itself as well as the required distance to combustible surfaces. Conventional furnaces are usually mounted in a cabinet and take away cabinet space.
__________________

__________________
Andy B is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yes!! A Great Vented Catalytic Heater S Sato Modifications, Alterations and Updates 35 02-06-2017 11:41 AM
Heater Kevin K Problem Solving | Owners Helping Owners 5 09-29-2007 04:31 PM
Heater Help Joe Mielke Problem Solving | Owners Helping Owners 11 06-13-2007 03:39 AM
OK, I need a heater. But where to put it? John McMillin Modifications, Alterations and Updates 7 01-24-2006 10:07 AM
Mr. Heater Buddy Portable Propane Heater Legacy Posts Problem Solving | Owners Helping Owners 16 08-03-2003 01:01 PM

» Upcoming Events
No events scheduled in
the next 465 days.
» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 12:25 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.