Dead furnace

Originally posted by techntrek  Have you checked all of the fuses to make sure the one for the furnace isn't blown?  I also just read there is likely a circuit breaker either under the front cover of the furnace or behind the furnace (don't know why it would be back there).

The only fuse I know about is the 7.5 amp fuse in the main fuse panel and it's fine.  All the fuses there are fine.  I have the cover off the furnace, and don't see another fuse.  There is a black button thing that I think is hooked straight to the thermocouple.  It's pushable but doesn't do anything for me.  There is a circuit board at the furnace, mounted sideways, at right angles to the front of the furnace.  I can see an off/on switch on there that is on, but without pulling the furnace, I don't see how to access the circuit board.  That would mean disconnecting the LP copper pipe, which seems like a last resort to me.  And the furnace definitely won't work with no LP, so other than something very obvious like a blown fuse, there's not a lot of point in my pulling the furnace out.

If we know there is a fuse there it might be worth it.  I'll see what the manual for the furnace says about that.  The manual has not been much help so far though.

TT

Well, the thermostat works for every thing but the furnace.  I've tried shorting it every way that makes any sense at all.  The furnace wire to the thermostat ground wire does make a barely audible muffled little click at the furnace, but still no heat or furnace fan.

Any other thoughts?  Does it seem prudent to replace the thermostat still?

TT

I think you will find that shorting the white and green wires is what you want to try. You said you had ruled out the fuse, so it almost has to be the stat or wireing..

The following are the wire colors used in a 5 wire thermostat cable. if it is hooked up correctly by installer.

• G – Fan, usually a green wire
• R – 12 Volt usually a red wire 
• C – 12 Volt Common usually a blue wire
• Y – Cool, usually a yellow wire
• W – Heat, usually a white wire

Originally posted by Tars Tarkas I'd like to figure out how to bypass the thermostat though to start the furnace just to ensure the problem isn't on that end.