I just found this site a few days ago and I'm quite impressed at all the knowledge here! That said, I'm hoping some of you can help me out...
I have this OLD Silver-Line gas furnace that was made in Winnipeg, Manitoba at least 40 years ago(has a service sticker on it from 1969). I've owned this house about 8 years and the furnace has worked flawlessly until about two years ago when the burner wouldn't light. I cleaned the wire splice(they were just twisted together) between the thermostat wires and the wires to the furnace and it fixed the problem until last spring when it happened again. I cleaned them and this time used a crimp connector for a "permantent fix" which worked until last week but now the burner won't light again. Actually the burner does light and stay on IF I jump the thermostat terminals on the gas valve OR touch my two crimp connectors together but not if I jump the wires up at the thermostat....odd.
I believe the furnace uses a millivolt gas system because it only has two wires at the thermostat and no house supplied power source except for the fan motor. It looks pretty simple, a thermostat, gas valve, over heat mercury switch and what I believe is a thermopile all connected in series.
I'm now wondering if maybe the thermopile is getting weaker over time and now it's at the point where it can't open the valve with the full circuit but can hold it open once the gas valve is jumped?.....
The thermopile puts out about
>215mv with just the pilot light on
>270mv with the burner on(checked just after the burner is turned off)
My problem is that I can't find any specs on what the thermopile should put out or what the gas valve should open at so maybe some of you guys could give me some advice? Without any specs how can you tell if the thermopile or the gas valve is bad? ......or could it somehow be the wiring??
Any advice is appeciated!