Dou Thermo Furnace burner and fan going but no heat.

[kreipe]

I've got a Duo Therm model 90030-812 C and have a recent and unusual issue.

The blower comes on and the furnace fires about 5 seconds later and stays lit (you can hear it). The problem is that the blower continues to blow cold air and all the heat comes out of the exhaust flue outside. There is an extra strong fuel smell outside of the unit as well.

Can anyone assist in diagnosing?

Thanks!!

[kreipe]

Thanks guys. I just removed it from the RV and I see a small hole where the exchanger meets the burner box.

So I'm guessing the issue was caused because blower air was flowing into and affecting the combustion air.

[Francesca_Knowl]

kreipe wrote:
There is an extra strong fuel smell outside of the unit as well.

Can anyone assist in diagnosing?

Thanks!!

If you're smelling raw, unburned propane, turn it off and take the rig/questions to someone that knows what they're doing so they can do a hands-on diagnosis of its source/cause.

And sooner rather than later!

[Dakota98]

Found this information online. It may be a starting point.

QUOTE:

"The most common cause of this problem is that the LP pressure at the regulator is too low or the regulator is bad. This should be tested at least once a year. You can take the regulator off and into a shop to be tested if that is more convenient. You need to examine the combustion chamber of the furnace as this is apt to get a hole burned in it and this can be dangerous."

If you are getting hot air from the exterior vent, it sounds as though the combustion chamber does have a hole in it & the heat is escaping to the outside.