# Low Fan Speed on Furnace?



## chetlenox (Feb 3, 2004)

Hey all,

One quick question, has anybody gotten their furnace unit running on low fan speed instead of "Auto"? Mine is the Carrier AC/Heat combo unit in my 2004 28RSS using the little remote jobby. I click the fan speed button but it just beeps at me and stays on "Auto". I would assume that "Auto" means "High", since it pretty much sounds like a 747 taking off when that sucker fires up at 3am.









Thanks!

Chet.


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## camping479 (Aug 27, 2003)

I don't think you can slow down the furnace fan. It's probably designed to have a certain cfm of air pass over the heat exchanger to keep it from overheating. Would be nice to have it quieter though, although we've gotten used to it. Price you gotta pay for being warm I guess









Mike


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## chetlenox (Feb 3, 2004)

Mike,

Makes sense.

Thanks!

Chet.


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## Cats4Nat (Jan 28, 2004)

There was another post about if there was more air flow, it would not sound like 747. I think ceramic heaters are the best so far, although we are planning to add extra air intake next to fire extinguisher in our 25RS-S.


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## Y-Guy (Jan 30, 2004)

Yep fan speed only works for the A/C, I tried it on my furnace too.









I love the ceramic heaters when I have hook ups, quiet and cheaper than propane too.


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## chetlenox (Feb 3, 2004)

I have a ceramic heater that I use in my garage, I'll have to give it a try. I'm guessing that I'd have to get another one for cold nights though (one for the kids bunkroom, one for the slideout queen on the other end of the rig).

I've always thought that the forced air propane furnaces are the weak point of the whole electrical system on these (or any, really) trailers. I mean, if I don't have to run the furnace I could go for a long time on my two measly stock Group 24s. Hot water heater, frig, stove, oven, everything running nicely on propane (except the lights). As it is, the furnace drains the batteries in a day and a half. I'm sorta surprised no one has marketed and started putting into trailers small, self-contained radiant heat propane heaters (catalytic? or maybe even conventional "burn" type) that are externally vented and heat the local area. Sure, they wouldn't work nearly as fast as the forced air furnaces we have, but with one at each end of the trailer it would work great for camping in cold temps where you don't have hookups. Would also be nearly silent, another plus.

Of course, I could just bite the bullet and buy a generator, but that would be too easy...









Chet.


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## Y-Guy (Jan 30, 2004)

chetlenox said:


> I have a ceramic heater that I use in my garage, I'll have to give it a try. I'm guessing that I'd have to get another one for cold nights though (one for the kids bunkroom, one for the slideout queen on the other end of the rig).


Chet FYI, if you plug the heater in at the front of the camper, don't use the plug by the sofa/bathroom as they are all on the same circuit, used the plug by the folding table instead.


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## chetlenox (Feb 3, 2004)

Y-Guy,

Thanks for the tip, I'll use the folding table plug instead. I also like Schantz's idea of running the Carrier fan on low to help circulate the heat. I honestly have never checked how loud it is on low (we've never even run the A/C), so it might be reasonable even in the evenings.

We are headed out this weekend, so I'll be able to give it a try shortly.

Chet.


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## Y-Guy (Jan 30, 2004)

Chet, try the fan on low as Paul suggests. I did run it for a short while but it seemed to chill the camper down to much. I don't know if the fan pulls any outside air at all, I know I felt the draw inside the camper, but soemtimes they draw some fresh air too. I have two bunk light/fans that I would like to mod to use in our camper to circulate the air since they are quiet and farily low on the amp draw, but its low on my mod list since we have hook ups at many of our campgrounds this summer and with the A/C I don't think it will be a high need.


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## aplvlykat (Jan 25, 2004)

Hi chet, I gave a quick look at the suburban heater manual( page 5) and it looks like they put in a single speed fan. The fan motor is a double shaft type and serves two purposes, 1) move air across the heat exchanger, 2) provide outside combustion air for burner effientcy and to purge the heat exchanger before start-up. You do not want to slow down the fan for the above reasons the only way you can make it quieter is to insulate the cabnet, remove the unit and put insulation under the unit to isolate vibration, open up the return air opening to slow down the whoosing noise. hope this helps, Kirk


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## chetlenox (Feb 3, 2004)

Y-Guy,

I'll try and give it a shot this weekend (ceramic heater + fan circulation) and see how everyone likes it. I would have guessed that the air is just internally circulating, but if you are feeling a good draft it might be drawing in some outside air.

Kirk,

Thanks for the tip on the manual. I always hate it when I have to read those things...







I'm remembering that a lot of the noise is the "whooshing" of the return air duct (as opposed to the fan or propane burn noise). But I'll give it a little closer listen this weekend. If it is, I'm not sure what else I could do to improve the situation, maybe add another return opening on the other side of the dinette. If I get some time this weekend I'll do some digging..

Chet.


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## aplvlykat (Jan 25, 2004)

I have to agree that this model of suburban furnace is very loud. We had one in our old motorhome, it was located under the bunk bed where the kids slept, it was so quiet you had to get down on all fours to hear it run. Makes one wonder what they changed?? Kirk


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## chetlenox (Feb 3, 2004)

All,

Just a quick update on my trial run of the ceramic heater + fan trick during this weekend's camping. Turns out that technique doesn't work well at all when you leave the ceramic heater at home!









Anyway, I'll try again NEXT trip...

Chet.


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