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No voltage to Bryant 373LAV igniter

1057 Views 2 Replies 3 Participants Last post by  HVACDave
The furnace will not fire.

The insides are clean. It has been running fine. The filter is now new, but the old one was not horrible. We had some significant wind recently, but none of the limit switches are tripped.

When I reset the power, the big blower runs about 90 seconds, the small blower runs for about 30 seconds and you can hear a faint click followed by a louder click like it is trying to light, but it doesn't. It does the click sequence 3 times then shuts down with the ignition lockout code 13 I think it was.

The igniter does not glow red but shows a complete circuit with the continuity tester. During cycles I can hear and smell the puff of gas, but no ignition.

I tested the 120v to the igniter, but for the most part that was zero all through the sequence with the following exception. When I hear a faint click soon after the small blower starts, I see a momentary blip of voltage going to the igniter but it instantly falls back to zero. It happens to fast I cannot even see a number. About 15 seconds later I hear a louder click and smell & hear the gas.

I did not see where any limit switches have tripped. I pressed the center switch on three. I checked 4 total and they are complete circuits showing continuity. 2 were above the burner, the main one in the firebox, then another up top.

The green ground at the burner is firmly attached now. It was slightly loose.

This unit has ran fine for 20 years.

Could it be anything other than a bad control board ? Thank you in advance.
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Sounds like the most likely candidate as you should be seeing voltage to the ignitor once the pressure switches have closed for approx. 20-30 seconds before the gas valve opens. I believe the timing for the ignitor is in the board. Sounds like the rest of the sequence is normal.
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