Furnace gas valve won't open


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Old 12-07-09, 04:10 PM
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Furnace gas valve won't open

I have a goodman furnace that is not lighting. There is only 15 volts getting to the gas valve. What should i be looking for? Circuit board has constant red light meaning all is well.
 
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Old 12-07-09, 05:16 PM
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Take the cover off the burner compartment of the furnace.

You should find a rating plate with the model of the furnace. Post that here.

Then turn down the thermostat until everything is shut off. Have someone turn the thermostat up and record the sequence of events that happens. You may need to do that several times until you have recorded all the details of what happens.

Post that sequence of events here. That should give us a reasonable idea of how far the furnace get towards providing you with heat, and just where it stops in that sequence.
 
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Old 12-07-09, 05:30 PM
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call for heat.
induction fan turns on.
10 seconds later ignitor begins to glow.
no ignition.
ignitor cycles every 20 seconds or so.
no ignition.
control panel shows constant red light.

goodman gmp075-3
 
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Old 12-07-09, 06:06 PM
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Check the spill/flame roll switches that are wired in series with the gas valve and located around the burner box. If any switches are tripped you will experience the problem you describe. Reset any tripped switches by depressing the little pin between the two purple wires on the switches. You will feel a click if it is tripped. If any switch continues to trip you will need to have the heat exchanger checked.
 
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Old 12-07-09, 06:08 PM
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Check and see if the terminals on the gas valve get energized with 24 VAC after the ignitor turns on.


Also, check for 24 VAC from the C terminal on the circuit board to the terminal on either side of the pressure switch when the thermostat is turned up.

You should see 24 VAC switch on when the inducer motor comes up to speed, and stay on. If it shuts off while going through the ignition cycle, that's a problem.


I don't think there are any diagnostic lights on this furnace, but please tell me if I'm wrong. If so, what is it signaling?
 
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Old 12-07-09, 09:14 PM
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I'd unplug the 2 wires to the gas valve and measure for 24 volts across them after the ignitor initiates.

The fact that the LED does not indicate a problem, sure points to a faulty control board though.
 
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Old 11-21-12, 09:19 AM
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rbron

I have the same problem! I have replaced the valve and the board. I still get the same results. What else could be wrong?
 
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Old 11-21-12, 10:31 AM
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Please don't revive an old thread. start a new one as follows:


Take the cover off the burner compartment of the furnace. Obtain the make and model of the furnace off the rating plate in the burner compartment and post it here.

Observe the sequence of events that occurs at the furnace when you turn up the thermostat and post that sequence of events in order and in detail.
 
 

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