I am not a technition or anything but I do have a question regarding to heating. Last winter I have the circuit board replace by local technition and the heat work fine. Now this winter, just yesterday the heat won't work. Everything seem normal. It start and blow gas as it suppose to. But somehow there is no spark from igniter. What could be wrong?

Model gmp100-3
Ser. 9707835783

Any answer would be appreciated. Thanks u...

I don't think your unit has a spark ignition, I believe it is a hot surface ignition. If so, check the glow plug (hot surface igniter) for power when it should be glowing, or check the igniter for continuity. Or call the service tech back and have them trouble shoot it. If the gas valve is kicking on, then back off with no glow at all, you have either another bad board, or a bad igniter. Please let us know what you find.

The timing is off somewhere,, the gas valve isn`t supposed to open to let gas out until after the igniter comes on and stays on for a short few seconds

Correct wmproop. However, If the igniter is bad and doesn't glow or spark, the gas valve will still kick on for a few seconds until the boards realizes there is no flame sensed, then it cuts the gas back off. You know this, Im guessing it was a long day for you too. Have a good night man.

I have to give in to the man... I do this kind of work now only as a part time job,just 4-5 hours a day after my full time job is over, there's a lot a fulltime everyday HVAC tech see`s and knows better than me,, have a good night my friend

Holy cow, wmproop. Are you a workaholic or what. Your making me feel lazy here, lol. But really, Ive seen the answers you give here, and I know that if the furnace was in front of you, you would know right away what the problem was.