no furnace fan??

[JSzewczyk]

Had a problem this weekend at the Martinsville race. We set the heater on and went to bed. In the morning i had dead batteries. while charging the batteries the next day, I dicovered that my furnace would trun on, light up up but had no fan blowing. The exhaust was coming out rather hot, but I was not getting any flow out of the registers. THe fan switch on the thermostat did not make a difference either. I moved the switch from high to low but it made no difference. I took the cover off looking for a loose wire or other simple fix. I also checked out the thermostat's wring and it was all good. Anybody have any thoughts?

 

[HighRanger]

If this is in a camper there is some sort of temp control that turns the fan on when the furnace gets hot. No power thru that, no fan. Might want to gram a meter and the wiring diagram and chek your power route. could be a bad fan motor, if it is the motor would likely be hot as hell after a minute or two of the t stat calling for the fan and it not running.

 

[Prairie Dog]

Take of the front cover and look through the exhaust for a bug nest, also check for a bad sail switch. You may have to do a little more disassembly to really check it out but it's not hard to do.

 

[JFaughn]

The fan & sail sw. have to work to turn on the gas valve & ingniter , if its lighting up then I would think that the curcuit board is bad .
I had a hornets nest in mine this fall , I saw them going in & out last summer , so I put a pice of metal screen under to outside exhaust , but it was too late , they had built a nest in by the sail & it keeped the furnace from turning on .

 

[CPittman]

Definitely get the mud dauber screens:

http://www.pplmotorhomes.com/parts/rv-furnaces/mud-dauber-screens.htm



and, if you have to replace the circuit board, get the new one from this guy:

http://www.rg-electrospec.com/



Oh, and get the one with the "fan control"



I agree w/ JFaughn, the system usually kicks the draft fan on which activates the sail switch before the regulator opens to flow gas and hit the igniter... HighRanger is probably dead on: bad fan motor.

 

[Prairie Dog]

Definitely get the mud dauber screens:

http://www.pplmotorhomes.com/parts/rv-furnaces/mud-dauber-screens.htm



This brings up an intesting question. Every rv furnace I've owned has stated in it's manual that you shouldnt use these screens but I've always done so anyway (I'm a rebel I guess).

I wunder why they whine about them?

 

[HighRanger]

Screens can get clogged with dirt and debris, they tell you not to use them to absolve them from any liability. Its all about liability.