Furnace not working

[Danorske]

Help me please,
My furnace will not ignite nor even try. It worked fine in Sept. Now I went out to start it for some cold spells and it don't. everything on Propane works OK.

I don't even hear any clicking from the igniter. zip, nadda. Check all the fuses they are OK.. I must be missing something. Any ideas to check on?

Thanks,
Ron

[BryanL]

One of the better diagnostic guides I have seen is rx4rv. The basic idea is to connect an ammeter across the thermostat.

Quote:

What these readings told me was 1- the relay was good and the furnace had power (the initial high amperage reading was the heating element in the relay heating up), the second amperage jump (after the blower came up to speed) told me that the limit switch and sail switch were both OK, and power was getting through to the circuit board, the last amperage jump told me that the gas valve was getting power, and the circuit board was opening it. (A side point is that the final amperage reading- 1 amp- is the setting that the “anticipator” should be set at on mechanical thermostats).

I have also found that some furnaces don't have enough airflow and end up cycling on the overheat safety which isn't designed for a lot of that so it fails. My current project is a furnace where the lead from the coil to the spark gap terminal was a bit loose and corroded. That also needed a new gasket (but the bad gasket did make it easy to see what the spark gap was doing!).

It is also easy to check the plug at the furnace to make sure you have good power and thermostat closure. I'd also check any wire terminals to make sure all are tight and solid.

[EngineerMike]

Ron- my thermostat has an on/off switch. Occasionally I forget to turn it on.

I once had a no-start condition, turned out I had pushed something against the furnace sheet metal box enough to tweak it so the closure-safety wasn't making contact. I just needed to take the cover off & de-tweak it.

[Danorske]

Thanks guys
My thermostat is the remote kind, That also controls the AC and fan. This afternoon I again took the cover off. Really didn't see anything, I touched the wire loom it then heard some clicking noise, and saw a LED lite on the PC board going on and off and the fan try to start. some more wiggling and the fan stayed on then it ignited to furnace burner. wiggling some more I could make it go off and on. So I guess I've kinda found the problem area. Now to figure out which wire is loose and it should be OK.

Ron

[powerboatr]

Quote:

Originally Posted by Danorske Thanks guys My thermostat is the remote kind, That also controls the AC and fan. This afternoon I again took the cover off. Really didn't see anything, I touched the wire loom it then heard some clicking noise, and saw a LED lite on the PC board going on and off and the fan try to start. some more wiggling and the fan stayed on then it ignited to furnace burner. wiggling some more I could make it go off and on. So I guess I've kinda found the problem area. Now to figure out which wire is loose and it should be OK. Ron

wow
i was going to say the RED off switch outside, i forget that puppy

good thing you found a loose wire loom, i need to check mine now

[Danorske]

Quote:

Originally Posted by powerboatr wow i was going to say the RED off switch outside, i forget that puppy good thing you found a loose wire loom, i need to check mine now

What red off switch? Do you mean toggle switch on the furnace behind the panel that you have to remove to access the furnace? Mine isn't red but is labeled reset and off.

Ron

[powerboatr]

Quote:

Originally Posted by Danorske What red off switch? Do you mean toggle switch on the furnace behind the panel that you have to remove to access the furnace? Mine isn't red but is labeled reset and off. Ron

yup mine is half red and black.

on my first rv i forget more than once