Propane furnace will not ignite

[Horsetime]

When we purchased our home the inspector was unable to test the furnace due to what they thought was no propane in the tank. When we got the propane filled we discovered some issues.

It's a UltraSX80, and we had the furnace valve, the pilot, the igniter, and the thermal couple replaced. Later in the winter the control board went down so we had that replaced.

It's our first year in an old house if you can't tell and a new furnace will wait. The inducter motor is working. We got a new propane delivery today, it was at 10% from last winter and tried to turn on our furnace, the pilot igniter will turn on but does not light the propane. We can manually ignite the pilot with a flame but the pilot does not heat up the thermal couple and the unit shuts down. The flame is blue. We have checked all safety switches, the unit will fire up but will drop out due to lack of pressure. The valve on the propane tank is open, and pressure regulator on the side of the house is open. Any suggestions?

Does anyone have any ideas? We used a family member in the HVAC business but he's out of town and if it's something simple we're missing I'd rather save the money on a call to someone else on a weekend.

 

[Silentrunning]

The only idea I would have is to follow the feed line from the tank to the furnace. Check every inch of it because there may be a kink in the line or another valve hidden away somewhere. Also, check your tank to be sure it is still full. There may be a leak somewhere.

 

[SandburRanch]

We recently had a propane water heater that would only burn the pilot. I disconnected the flex line at the heater, turned the supply line valve on and there was only a short burst of gas. A new regulator solved the problem. Ours has the regulator on the tank and is set for 14" water column.

 

[Horsetime]

Hi! It's been a year and our furnace works fine now. What we discovered was that the control board went out again. What we didn't know the first time was that moisture in the basement caused water to collect on a pipe and drip on the control board, so when we replaced it the first time we never caught the reason it was rusty. We ordered a new board and moved the pipes so they weren't over the furnace.

 

[SandburRanch]

Glad you solved the furnace problem and I realize from your OP this is an older house, but basement moisture and the pipe temperature that's causing the drip in October is interesting because that would concern me of other elements in the basement suffering from a moist atmosphere. There is a chart I find handy to calculate those conditions and if you be interested I can post it as a link.

 

[argile_tile]

It's a UltraSX80, and we had the furnace valve, the pilot, the igniter, and the thermal couple replaced. Later in the winter the control board went down so we had that replaced. It's our first year in an old house if you can't tell and a new furnace will wait. The inducter motor is working.

MECHANICS DO NOT THROW PARTS. they veryify (by any method) what part work and test any part in question (ie, bench test).

You still have the VACUUM that detects if the hot gas inductor motor is blowing.

You have the furnace temperature sensor, which senses if the box is too hot.

> We have checked all safety switches, the unit will fire up but will drop out due to lack of pressure.

You said you replace your tanks, tanks full, and the whole rail. So lack of pressure isn't possible according to your previously saying the gas handling equipment (including control valves) were replaced.

ALSO: A UNIT WITH AN IGNITER DOESN'T HAVE A PILOT LIGHT - that's a contradictory statement

 

[Horsetime]

This post is 2 years old. Thanks for the advice! Furnace works fine now.