furnace issues

**redfish bayrat** · #1 06-28-2012, 04:42 PM

Last two winters have been pretty cool in my trailer. I cannot get the furnace to kick on. Trailer is a 1991 Wilderness Cimaron. Furnace looks like it has never been used.
I've checked fuses, etc. A/c works, but when I put the thermostat on heat and the gas is on, nothing happens. I've read that the furnace has an electronic ignition system. Any suggestion on where to start looking before Deer season?

**jesley22** · #2 06-28-2012, 06:13 PM

The problem I had with mine was mud dobers that made nest inside, had to take it apart to get them out. would have never known this unless I took it apart. They have a outside screen that can let bugs in, this what the rv people told me to look at first. I do know that the gas will not come on without ingition and you do need the battery on the trailer to make the inside thermostat to work.

Good luck

**seabo** · #3 06-28-2012, 07:13 PM

yes for sure it needs to be checked for nests and any blockage and make sure the blower will spin by hand it may be frose up not being used. usually,when you turn the heat on the blower starts blowing then you hear a click and hear the flame ignite, then it starts getting warm .so if its not blowing at all its either frose up or its not getting power. dont eliminate the thermostat in all this either. good luck and the way mine works is if your plugged in to 120, the convertor runs it on 12 vlts.battery or no. the reason i know this is because my convertor was over charging my battery (17vts). so i would un hook it when i plugged in and i remember running the heater .but i replaced a fuse in the convertor and now its charging 13vlts. i wouldnt have thought a fuse would fix it . anyway, i hope this helps. oh also the heater and ac are two different units not connected any way .

**redfish bayrat** · #4 06-28-2012, 08:09 PM

Thanks for the replys. Trailer was in Goliad for many years and now it is in Columbus where I know we have plenty of mud dobbers. Will check it out. Battery is brand new, but I have not checked the voltage yet. Going up there tomorrow. Thanks again for the hints.

**Ducatibilt** · #5 06-29-2012, 02:35 PM

If the fan is turning and it's just not igniting one of the common problems is the sail switch.
It's basically a micro switch with a small aluminum arm on it, the fan has to be pushing enough air for the arm to activate the switch before the the furnace will ignite. They tend to collect dust and get jammed up or just wear out.

Ran into this on mine before, pretty simple repair if thats the problem.

**redfish bayrat** · #6 06-29-2012, 11:01 PM

I get nothing when I put the thermostat on heat and up to high temp. No fan, no nothing. Saw some videos on youtube about the furnace and they were helpful along with the suggestions here. Thanks again.

**smokinguntoo** · #7 09-06-2012, 09:40 PM

Check for moisture plugging the gas line. Pain in the arse to do but disconnect and physically blow out the line. There may not be enough propane pressure to clear it out. While you are doing it operate the thermostat to see if the gas valve is opening. Or use an ohm meter to ck continuity in the valve. Be sure to buy the stainless mud dauber screens for the heat exchanger outlets. I must have cleaned 2 pounds of nests out of one unit. First cool front on the way.

**smokinguntoo** · #8 09-10-2012, 07:35 AM

BTW: I could hear the gas valve operate but no gas came out the orifice. The moisture issue I spoke of was downstream of the gas valve. I removed the small copper line at the gas valve and physically blew it clear with my breath. Hard to believe that the propane pressure wasn't enough to clear it, but it wasn't. This was a new unit about 4 years old that had never been used previously.

**sferg** · #9 09-12-2012, 10:20 PM

Unless you get the inside of the trailer into the 70's by running the a/c , it might just be too warm to get it to come on. Otherwise, Check for 12 volts at the circuit breaker in the furnace itself. The board , when activated turns on the fan after a short delay, When the can blows air on the sail switch, it closes the switch which allows power to the gas selonoids and releases fuel. Then the igniter send power to the electrode which lights the flame. I had a problem with my thermostat where a little resister wire had melted into the plastic and nothing would come on. I replaced the thermostat with a $19.00 wlamart hunter digital and problem was solved. The number 1 problem with furnaces is bugs or dirt dobbers. Always pull the burner and blow it out every fall, Be sure to remove the orfice as a spec of dirt will prevent it from ignition. The tail tail sign of a dirt bobber nest in the furnace tubes this is the unit light and the flame will go out almost immediately. What type of thermostat does it have? An old style analog > If so replace it first if the unit seems dead. If you get it cool in the unit and the new thermo fails to solve the problem, replace the dinosaur board. The the power at the circuit breaker, again. The schematic should be on the inside door of the furnace.