New Cougar - Furnace wont heat above 60

Chris Bryant wrote:

nebmike wrote:
One final question for you fine folks... during all of this I noticed that the rear panel on my furnace (where the three main ducts come off of) is a bit crooked and there is quite a bit of heat escaping around the edges of it. Would it be worth my time to tape it with some aluminum tape or just leave it be?

Seal it up. That hot air will be drawn back in to the return, causing overheating.

That was probably original issue with 'limiting'

Addition of extra duct allowed more discharge flow that was most likely blowing out around gap at a higher rate/temp.
Sealing that leak would have probably cured initial issue w/o new limit switch, new additional duct and new registers.

Any leaks not into the living space can be taped up.
If you are warm in 15 minutes I can't imagine the furnace is undersized.
I have always thought if RVs were better built we would not need such large cooling and heating equipment.

The fact is, you have an undersized Furnace. NOTHING changes that. Doug

nebmike wrote:
One final question for you fine folks... during all of this I noticed that the rear panel on my furnace (where the three main ducts come off of) is a bit crooked and there is quite a bit of heat escaping around the edges of it. Would it be worth my time to tape it with some aluminum tape or just leave it be?

Seal it up. That hot air will be drawn back in to the return, causing overheating.

One final question for you fine folks... during all of this I noticed that the rear panel on my furnace (where the three main ducts come off of) is a bit crooked and there is quite a bit of heat escaping around the edges of it. Would it be worth my time to tape it with some aluminum tape or just leave it be?

Thanks for all the great advice and suggestions, everyone!!!

I picked up a limit switch and swapped it out. Also changed all the floor registers to a design that is less restrictive than the originals, and then plumbed in an additional duct off of the furnace (pics). The furnace sits directly behind the panel where I installed the white fixture. I drilled the door and installed a vent so that they line up when the door is closed.

Works perfectly and it got up to 72 degrees within about 15 minutes or so (that's just where I had the thermostat set - I'm sure I could go warmer if I wanted). Its 32 outside right now. This morning when it was 35, I couldn't get it past about 60-62 even after it had literally been running non-stop all night long.

Y'all are awesome! Now, off to pack for a short maiden voyage this weekend...

If I recall old school rule of thumb was 1000 btu per foot rv foot. This was way before slides though.

nebmike wrote:
Also, it seems as though every few minutes it'll blow cooler air for a while and then go back to somewhat warmer.

This sounds like the burner is cycling probably due to inadequate airflow causing the high limit switch to open for the heat exchanger to cool. Listen very carefully and you should hear when the burner kicks back on. Harder to tell as it shuts down. Cycle maybe every 1 or 2 minutes.

My main duct in the floor was collapsed as built new. Did my best to prop it open but the solution was to add two more ducts. I assume yours is different but similar issue.

I went thru this last year with a Cruiser Travel trailer. The customer had the exact same problem on a 28 foot with 1 slide. They installed a 20k Suburban. I do not have the formula at home, but Suburban gave me the number you use to take the Square Foot of the trailer and the number you multiply with to get the BTU size furnace. I had to remove the too small Furnace and `since the larger would not fit in same exact spot I had to install a 30k and cut a hole in the side of the trailer where the old furnace was. Cruiser also denied and stated that that furnace was the correct size, but after I gave then Suburbans figures they paid for the modification. If you call Suburban they will give you that figure to use. The 30k was just at the limit for this size trailer. I can guarantee you, your furnace is WAY undersized for your size trailer. Doug

Are there any fault codes for these furnaces, like on home models?

I know my high limit switch code on my home furnace by heart now.... It wasn't until I went through 2 of them that I found the culprit ... 2 filters shoved up inside the air return from the sheet-rockers when the house was built. Hasn't blown another limit switch yet. It isn't always the warm air registers that are the problem.

Hope you find the reason IF it does turn out to be the high limit switch. Something constricting airflow is the most likely, as others have pointed out.