heater failure in cold weather

brodavefla · 09-21-2021, 05:24 PM

Hi all,

We're two weeks into our great fall RV adventure, by far the longest time we've been on the road--will be 2 months total. We're in the West Yellowstone area now, and had a low of 30-ish early this AM. Our TT wasn't much warmer than that! After quickly checking to make sure we still had 50 amp power (and cranking up the furnace), I turned the heater off, waited 30 seconds, and turned it back on. The central heat/AC unit (Airxcel 48000 series, with a wall thermostat) kicked back in and provided warm-ish air into our TT, but shut back off after 2 or 3 minutes. This cycle repeated itself for the several times I tried it. We've been using the heater for at least a week and haven't had a problem until now, though it hasn't been this cold for us until now.

After that we took off for the day. Upon returning, the outside temp now is mid-50s. I've just re-tested the heater, and the same symptoms presented themselves. It does run for about three minutes, but the air blowing out never gets warm. I thought maybe the coils had frozen and might've thawed out but doubt that now. BTW the AC, which seems to be on the same fuse, works OK. (I'll send a pic of the fuse panel shortly.)

I'm no electrician but am thinking that the fuse is shorting out, tho I'm not sure which one it is, as the legend on the panel is kinda fuzzy. Also, presumably the fuses are behind the panel, which appears to be removable. Assuming that's the case, I would certainly turn off the power main before working on it. If that's what the problem is, what kind of store would carry replacement fuses? Any wise guidance would be appreciated!

Thanks, DC

brodavefla · 09-21-2021, 05:35 PM

Here’s a pic of the fuse panel cover

**JRTJH** · 09-21-2021, 06:06 PM

The "airexcell 48000" is a roof mounted heat pump. It is powered by 120VAC shore power when you're plugged into a campground pedestal.

The furnace is probably a 35K btu 12 volt "floor mounted" propane furnace and is powered either by the converter and/or battery depending on whether you're connected to shore power or using battery power.

There is a control box in the rooftop unit that controls the furnace functions via the "dual use thermostat" (it controls both AC and heat).

From your comments that the "heater runs for 3 minutes" I'd suspect you're describing a problem with the furnace, not with the heat pump. I'd suspect that you have a thermostat setting that's incorrectly selected.

I also believe you have a 5500 btu electric fireplace that you could turn on to take the chill off the trailer and likely provide all the heat you need for 30ish to 50ish temperatures. Doesn't your fireplace work ???

brodavefla · 09-21-2021, 06:34 PM

Quote:

Originally Posted by JRTJH

From your comments that the "heater runs for 3 minutes" I'd suspect you're describing a problem with the furnace, not with the heat pump. I'd suspect that you have a thermostat setting that's incorrectly selected.

I also believe you have a 5500 btu electric fireplace that you could turn on to take the chill off the trailer and likely provide all the heat you need for 30ish to 50ish temperatures. Doesn't your fireplace work ???

I appreciate the nomenclature clarification. Yes, it's the furnace, not the heat pump. And we do have the fireplace, which I was calling the furnace. It does work, tho won't completely warm us for the expected low of 22-ish tonight. (We stayed toasty warm last nite with a spread and electric blanket, and have a backup electric space heater, so no worries there.) As to "incorrectly selected" thermostat setting, I'm not sure what that could be, as we've done the same thing we've always done and, until last night, it worked just fine. And we have plenty of propane.--DC

brodavefla · 09-22-2021, 05:06 AM

"learning all the time", as Benny Hill used to say

First of all, we did get enuf heat from the fireplace to keep the TT at 60F thru a nite in the low 20s. I'm glad to have, with the guidance provided here, the understanding of which heat source came from which power source. Thanks for that. When we bought this unit used last year we did have most or all of the documentation that was provided to the original owner, but as newbies that left huge knowledge gaps which have only been filled incrementally and the hard way. Story of my life...

Anyway, with some early-morning clarity, I seem to recall that we had a similar problem sometime in our six short outings in the TT prior to this big trip. I think there is a protocol to go through in order to reset the furnace so that it would light the propane. If my memory was really good I'd remember what it was! I may have gotten the tip for that on this forum but I've been unsuccessful at searching for my own posts in the past.

rhagfo · 09-22-2021, 05:27 AM

My best guess on your furnace is an issue with the sail switch. If the fan can’t get the switch to activate the no propane flow.

wegone · 09-22-2021, 07:24 AM

You might want to try this....I bought and use a small ceramic electric heater that oscillates, and has tip over protection, and different settings for heat.
I plug it in a outlet, and forget about it, it keeps us perfect and its quite. It might take longer than my 35k but if you leave in on, it get to the same point soon enough....we just snuggle until does

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