Furnace not working

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Peteyboy

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Took the MH to a local shop to fix the furnace on our rig as it is completely unresponsive to the thermostat.  The little flame icon appears when you ask for heat, but no ignition, fan, nothing.  They just called to say they can't figure it out.  Will probably take it to the factory when I can, but does anyone have any ideas in the meantime ?  Can a separate thermostat be installed just for the furnace ?  BTW,,, the shop said they got the furnace to run from directly at the unit and it ran that way perfectly.
 
Yes, you could have a separate thermostat just for the LP furnace. (My coach has two LP furnaces, one with it's own t-stat and one linked to the heat pump in the main t-stat.) Having a separate t-stat would not allow the heat pump lock-out mode that kicks on the LP furnace to work, but that wouldn't be a big deal in my opinion.

I am puzzled as to why the shop can't "figure it out." I would think that any competent shop would be able to determine whether or not the t-stat is sending the required signals to the furnace. It is possible the t-stat is defective, but they need to do some routine trouble shooting before starting to throw parts at it. I guess it is good that they admitted they can't figure it out rather than starting to do solutions that cost you $$$ and may or may not fix it!
 
Thermostat was replaced this summer for an A/C problem, so chances are that it is good. They did say that the thermostat signals are not reaching the furnace.  They said something about a secondary thermostat being in the system somewhere,,,, ??
 
If they cant figure it out they shouldn't be touching it. I would back track. They may have miss wired the thermostat when they worked on it last time. There are not that many wires controlling it so if a broken wire is suspected, bypass it. They already answered their own question and proved it when they jumped it directly at the furnace. I dont want to call them idiots but.....            What is the  model number.
 
What does your thermostat look like? Does yours control the heat and ac on the same thermostat?

Is it like this?

 

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Yep,,, thermostat controls both a/c's and the furnace.  Will try to work thru the manual but I am really a plug and play kinda guy, or if a wire is broken or disconnected I am a genius.
 
If your furnace works off the same thermostat as the a/c, chances are the heat-needed signal goes through the a/c zone controller. Almost guaranteed it does if you have heat pumps or multiple heating/cooling zones in the RV. Odds are both of those are true in your coach.

The signal to the furnace is simple - just +12v on a wire that [eventually] reaches the furnace. But if the wire goes to the zone control first, it may have been disconnected there, or conceivably the zone control board is faulty (rare).

What thermostat is it, and do you have multi-zone and/or heat pumps?
 
Thermostat is an RV Comfort.ZC.  Yes it controls everything with 2 zones. but the gas only works off the front a/c.
 
I did uncover both a/c units and both control boards have everything connected.
 
Looks like a fuse in that thermostat




FUSE
The thermostat is equipped with a replaceable fast acting 2-Amp fuse located on the base of
the thermostat.  The fuse is designed to ?open? if the appliance is mis-wired or there is a short
in the system.  If the fuse opens, the cause of the failure must be located and corrected before
the fuse is replace
 
QZ said:
Looks like a fuse in that thermostat




FUSE
The thermostat is equipped with a replaceable fast acting 2-Amp fuse located on the base of
the thermostat.  The fuse is designed to ?open? if the appliance is mis-wired or there is a short
in the system.  If the fuse opens, the cause of the failure must be located and corrected before
the fuse is replace

Took the original thermostat apart and if there is a fuse in there it is not like any fuse I ever saw.  Everything on the board is soldered into the board for sure.  The replacement thermostat looks exactly like the original.
 
Peteyboy said:
The control board does have terminals marked generator.

Look for a fuse on the base of therm. Check it with a low power test light or ohm meter. You mentioned your capabilities early. A visual inspection is a first step and then you start a process of troubleshooting. Most important is to not use any jumpers or accidentally shoot power to a circuit that blows out a control board or something. There is a point where you need to realize your limitations and maybe find a different repair facility.


Edit: Ok we were both typing. Is there a little door or plate or anything on the bottom?
 
Yep,,, I am  definately at my limits, so before I put 110 volts to a 12 volt system I will put my hands up.  Just have to stay above 40 degrees this winter which usually isn't too difficult in south Texas or Arizona.  Thank you for all the ideas and imput.
 
Peteyboy said:
Yep,,, I am  definately at my limits, so before I put 110 volts to a 12 volt system I will put my hands up.  Just have to stay above 40 degrees this winter which usually isn't too difficult in south Texas or Arizona.  Thank you for all the ideas and imput.

Dont give up yet. :) I was looking for a pic of the fuse location and only found this so far. Looks like it resets the system too.

http://www.winnieowners.com/forums/f259/rv-comfort-zc-issue-280415.html
 
Do you know how to properly program it? I know some modern gadgets will wear ya out until you learn it then we dont have a problem for a long time and forget it. Like my cameras and other stuff with too may features.
 
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