Need thoughts from furnace gurus......

[MiCarl]

An update:

 

Furnace crapped out again a few days after the new transformer went in. Manually lit it one time and it was fine for a week. Crapped out again last night and even after manual lighting several cycles it didn't resume firing the igniter. I jury rigged it so the pilot stayed lit to get us through the night.

 

This morning I put the replacement control on. Same thing, control complains of low voltage. This happens even with the gas valves disconnected. Conclusion: ICM Controls are junk.

 

I reconnected the original Johnson Controls G60RBG-3 and it didn't work, but with a different problem. Igniter was firing but the gas valves were chattering. Wiggling the wires I found the immediate problem. After re-connecting that wire the furnace worked normally again.

 

I noticed that the terminals on the old control are apparently steel and have some corrosion on them. I'm wondering if this is the source of my problem. Remember, after I'd disconnected everything to try the replacement control then switched back it worked for almost a year. I'm wondering if all the connect/disconnect cleaned them up enough to get me by until they corroded again.

 

I think the next warm, dry day I'll pull the control out and give all the terminals a good cleaning.

[Flyinfool]

Give all those terminals a good cleaning and a good coat of dielectric grease to help keep them clean.

[MiCarl]

Shortly after my last post the furnace crapped out again. Of course it was very cold outside. With all my messing around in there I'd finally figured out how things worked and re-wired it so the pilot would stay lit and got through the winter that way.

 

Honeywell makes a control that's supposed to be a suitable replacement for the Johnson Controls control that was in the furnace. The ICM control (2 different units I tried) is supposed to be a "clone" of the Honeywell. Last week I broke down and ordered the Honeywell control which I installed today. The furnace works flawlessly with the Honeywell control.

 

I guess the moral of the story is it doesn't pay to try and save a couple $$ with off brand furnace parts.

 

The other moral is it's way easier to work on a furnace when it's 73 degrees than when it's 2 degrees.

 

Thanks everyone who gave me input on this.