Goodman Gas Pack wont lite

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Old 12-31-07, 06:43 AM
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Goodman Gas Pack wont lite

I have a goodman gaspack that will not lite. When the t-stat calls for heat the electronic spark is sparking and about 15 - 20 seconds later the inducer fan motor starts but the pilot never lights. The pilot sensor and igniter is new. The model number is PGO42100-AB RevB. The inducer fan is making a noise but is turning. What should I check???
 

Last edited by skyjumper; 12-31-07 at 08:11 AM. Reason: additional info and spelling
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Old 12-31-07, 08:33 AM
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Generally speaking, the spark shouldn't turn on until after the inducer motor comes up to speed.

So I'd measure continuity across the pressure switch to see if it is opening and closing or stuck open.

When the pressure switch closes it should turn the 24 VAC on to both the spark to light the pilot and the gas for the pilot light. You need to check to see if the pilot gas is on, and if not why not. That could be things like the gas meter turned off, the gas shutoff valve at the furnace turned off, the gas control on the electric gas valve turned off, no voltage at the gas valve solenoid for the pilot burner or a plugged pilot.
 
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Old 12-31-07, 10:23 AM
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I have checked and all the gas valves are on ( and i do have gas in my tank) How do I check continuity and voltage at the gas valve.

Thanks
 
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Old 12-31-07, 12:01 PM
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Originally Posted by skyjumper View Post
I have checked and all the gas valves are on ( and i do have gas in my tank) How do I check continuity and voltage at the gas valve.

Thanks

Well, you need a multimeter with an ohmmeter and AC voltmeter, the schematic diagram that's usually posted in the furnace and an ability read read and understand the diagram.


If you don't have that meter or the skills needed, I'd look for a friend, neighbor, relative or repair company to help you.
 
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Old 12-31-07, 04:54 PM
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Did the tank run out and then you filled?

Is your weather where you are causing maybe the regulator- vent to be frozen over or something?

Did your problem occur out of the blue after it had been running fine recently? When is the last time it ran good?

Look for PV printed on control board and trace wire to gas valve that may have PV printed on gas valve. When you think it should be calling for pilot gas, meaure for 24 volts a/c at the gas valve PV (pilot valve terminal wire, not the MV, main valve gas terminal) between either 2 wires there or between the one PV wire and any sheetmetal on your furnace.

IF you show voltage, then I'd remove the pilot assembly to check the orifice. Propane pilot orifices are REAL tiny.

I too agree very odd the sparking is happening first. And also agree the pressure switch 24 volt test needs to be made. But here again, what is odd is there really should be no sparking unless the pressure switch is first sending juice to the control module.
 
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Old 01-15-08, 06:39 AM
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I replaced the inducer motor and now the electronic igniter comes on right after the inducer fan starts. The pilot did not light after changing the inducer motor until I was checking voltage at the PV terminal on the gas valve, then all of sudden the pilot light came on and the system ran fine for several days.

Now the pilot light will not come on and I show 2-3 volts at the PV valve. The inducer fan starts and the electronic spark starts but no pilot light.

The system was running fine until this problem occurred. I have gas and have never ran out, as I usually refill when I get to 20-25%.

Could the intermittent pilot control board be bad? How can I test it and what else should I check.

Thanks for you help!
 
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Old 01-15-08, 12:32 PM
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Originally Posted by skyjumper View Post
Could the intermittent pilot control board be bad?
Sounds that way. But wait for others to weigh in, as these can be a little on the expensive side compared to other parts.

How can I test it and what else should I check.
I think most people go through a simple process of illimination. If you have 24 volts coming in through the pressure switch, and the fact you are getting spark confirms this incoming voltage, I would then suspect the board.

But I would first perhaps disconnect the PV wire at the board to make sure you are not getting some ground-out occuring in the valve, that is taking away some of the voltage. If then, you get spark, but never no 24 volts from the PV terminal on the board to ground, then at least -I- would say it seems like the board.

But let some other people weigh in and share the responsibility.

Can you see anything burned on the board?, or is yours enclosed?
 
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Old 01-15-08, 01:13 PM
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My board in enclosed. The unit started working again this afternoon when I was trying to get voltage reading from the intermittent pilot control board. After it reached the t-stat temp it shut off and would not come back on when the t-stat called for heat again.

Again, Thanks for your help!
 
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Old 01-15-08, 03:55 PM
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Lots of mechanical things act up at first, sporadically, and then finally go out completely where you can finally catch it in the act.

I think I forgot to mention in my earlier response that to make sure voltage is not disappearing due to it grounding out somewhere, that you need to remove that PV wire, and then test. Either test at the end of the wire (making sure you do not contact furnace metal when pushing the test probe against it, or, to test for 24volts, when the PV wire is disconnected, right where it plugs in at the control module.

I think generally these enclosed intermittent pilot control modules are somewhat cheaper than the open board variety.
 
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