HAve replaced the inducer and blower boards, pressure switch, and wiring harness plus the bi-metal pilot assy.
The problem is that the pilot will light, burn for about 15 seconds then start popping off and on. Never have had the inducer start to make the pressure switch prove for main burner ignition. Correct voltages have been traced to each circuit...the last thing left is the gas valve...anyone have a suggestion?
Thanks!

Intermittent Spark or Standing Pilot Ignition

Intermittent Spark ignition Pilot Light Assembly For the Intermittent Pilot Ignition type, after the control board has confirmed that the inducer fan is in fact running or in the case with no inducer fan upon a call for heating the heating system[/URL]
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will open the pilot gas valve which is part of the main gas valve assembly and send high voltage to the spark igniter.

The Heating system control board confirms that the gas pilot has in fact lit and is burning with a flame sensor of some kind, this usually looks like a small metal cylinder that is in direct contact with the flame itself. The board then switches on the main gas valve that allows gas to flow to the burner assembly. The burner then lights and the flame should be uniform across all burner tubes and mostly blue in color where it can be seen.


CAUTION - Always be very careful with electricity as it can be lethal, if you are not comfortable performing any of these steps please do not perform them, of course you are performing these steps at your own risk.

Important Note: The heating system control board is sometimes very sensitive to static electricity, avoid touching this board to prevent failure.