Dometic Furnance Help

[cmgirdwood]

I have a 1985 345 classic motorhome with Dometic series 900 furnances. The rear works perfectly, but the front does nothing. I check the voltage on the thermostat and at the furnance, both read 12.5 volts. The propane gas line is fine. When I turn the thermostat above room temp, nothing happens. I would like to repair it myself. Does anyone have any ideas ? Thanks

[FrankR]

Hey Chris, It is necessary to include all the info ya can about a question. It is very difficult to trouble check anything from 1000 miles. I don't have a AS motor home, but I know electrical. Does this unit have 2 furnaces?? Also 2 t-stats?? Does the other LPG appliances in the RV work?? If this unit has just a single furnace, the ducting from the furnace must be restricted. If there are 2 furnaces and one will not lite, the LPG line must be restricted or blocked. The only goood test for the LPG supply is to remove the line from the furnace, and sniff for gas. A helper is good to have so as to turn off the main supply after smelling for gas. A furnace needs only a few items to operate, as at least 11 volts, fresh air and LPG fuel. If ya give me more, I can give ya more....... Frank

[PeterH-350LE]

could be your printed circuit board
try Andy @www.inlandrv.com
or
http://www.dinosaurelectronics.com/

[83Excella]

Chris,
I had a similar problem with my trailer and after checking everything I could and it still not working I decided to yank it out and while doing so I had to move some insulation and guess what? cant guess? I'll tell you, I found the electrical plug that plugs into the side of the unit unplugged, so I plugged it in and whaallaa it fired right up as advertised. Just to point out some fixes are not as difficult as they appear.

John (who's chillin no more)