no heat

[albionbryant]

I have a problem witha Bryant gas FHA furnace serial#7S57577. I took the pilot and escapment tube (which I thought was a thermocouple and cleaned it with steel wool) apart and the furnace lit and produced heat for a day. Now, the blower motor runs, the pilot is lit but no gas and no heat. Any ideas?Thanks.

[Java_Bob]

a disk type temperature switch turns the blower on when bonnet temp is reached, or if your furnance has a flame rollout sensor it will keep it running too, and not allow the main burner to come on untill it is reset. llok for a diagram on your cover..

[albionbryant]

how do I know what the problem is? Flame out switch or roll out sensor? Seems the roll out sensor would be the culprit if the motor is running and never satisifies the flame out sensor. What do you think?

[Java_Bob]

If that has a flame roolout it will cause this problem, shut unit off and look for a red or white button on a devise around the burner assembly

[albionbryant]

Thanks for the input. I got my electrician to come by to check it out and there was significant heat damage to the jacket, around the exhaust and to the wiring of the two limit switches. Diagnosis was a cracked heat exchanger. So, I guess a 40 year old furnace has met the end of the road.

This is a great resource and I look forward to contributing as I can.