Tony Hwang wrote in news:1Flqf.158519$ki.53095@pd7tw2no:

My Carrier furnace can go into test moce cycling thru it's sequences.
Just a mattrer of jumpering one pin. No such thing in your furnace?
If you do, you can observe what's going on.
Tony


Mine has that option too. Since it fires up and works fine once I cycle
the circuit breaker or open and close the door, test mode is not required.

Problem is intermittent. Woke up yesterday morning to a 50 degree house.
Today, everything is working fine. It's happened 3 times in a week. I
just never know when the thing won't work.