Is my furnace functioning properly?

[Horseshoe]

The Atwood furnace in my 2011 ATC Cougar seems to work fine. It blows warm air into the camper and I can't really complain. However the air being vented outside the camper is HOT. It does seem oddly inefficient and I'm curious if this temperature differential is normal. Any thoughts?

 

[Wandering Sagebrush]

I believe your talking about the exhaust, and yes... It's very hot, loaded with CO, too. You don't want that in the camper...

 

[Horseshoe]

Thanks! Yeah, I realize the exhaust needs to be vented outside, but did not expect it to be so much hotter. I'll stop worrying about it.

 

[MarkBC]

It's normal that the air being blown outside is hotter/warmer than the air being blown into the camper. The air being blown outside is the raw exhaust of the propane flame -- after passing over the heat exchanger that transfers some (ideally, "most") of its heat to the camper air. But the camper air will always be cooler than the raw exhaust from which it gets its heat for heat transfer to work. To get the exhaust temperature close to the camper-air temperature you'd need a really big/long heat exchanger.

To say how efficient it is you'd need to compare the temperatures and the volumes of air blowing out of the two ports -- to calculate what fraction of the propane-burning heat goes into the camper.
But, yeah -- it's a long way from being super efficient.
I wonder if Atwood makes a claim for efficiency somewhere...?

 

[CougarCouple]

Horseshoe if the temperature of the flue gas was the same, as the conditioned air, your camper would probably be on fire..

Look in the literature look for but rating input compare to btu output rating.

i.e. Residential type furnace of which there are several sizes: 90,000 btu 80% efficiency furnace has an input of 90,000, but only puts out 63,000 btus. A 70,000 btu would put out 54,000

Hope this helps.
Russ

 

[Horseshoe]

Yep this all makes sense. Thank you all for your input!