Goodman Draft Inducer Fan Keeps Cycling On and Off


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Old 01-05-09, 05:23 PM
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Goodman Draft Inducer Fan Keeps Cycling On and Off

Here is my situation:

I have a Goodman (gulp) gaspack Model PGB042125-1 that is approximately 8 years old. In the past we have had to repair the other regular issues (cracked heat exchanger, multiple bad igniters, burned compressor contacts, etc -- Thanks Goodman!), but I've got a new one and money is tight. The draft induction fan keeps cycling on and off -- regardless of whether the thermostat is calling for heat or not. The gas never turn on during the cycling and the igniter never glows, the induction fan just keeps cycling on and off and has been doing so for weeks. When the thermostat calls for heat, the unit works just fine. Is this a problem with the board that I keep reading about? I'm pretty handy with a volt meter but I have no clue where to start to diagnose the problem and I can't afford to either start replacing parts or pay for a house call to a professional to run the diagnostics. I've searched through the threads and cannot find an example of my problem. Please help me.

Thanks,

Walt
 
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Old 01-05-09, 05:34 PM
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Hmmm. Never heard of that one before.

But of course it shouldn't do that. To check it I'd test the voltage being supplied to the inducer motor and verify that it's coming from the circuit board.

If the parts on the circuit board are accessable, I'd look for a relay that might be turning on and off.

But absent some kind of creative rewiring which sounds unlikely on a new piece of equipment, I'd replace the circuit board. Some equipment has a separate circuit board to control the inducer motor --- you want to double check that although more than likely it's the main circuit board or module.
 
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Old 01-05-09, 05:39 PM
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I'd also check the stat and it's wiring, to rule that out. Disconnect W wire from low volt terminal strip in furnace to see if that stops it. If so, stat or wire shorting sporadically. If not, relay likely, that changes the 24 volt signal to 120 to the inducer.
 
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Old 01-05-09, 05:50 PM
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Ive seem this a few times with different types of equipment.
I believe you have ghost voltage running through your low voltage circuit. Don't know what causes it but seems to be more prevalent with Honeywell thermostats and circuit boards.
The remedy is to install a bleed down resistor between the W and C terminals on the circuit board. I'm not sure what the ohms rating of the resistor is but have seen them supplied with thermostats.
 
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Old 01-05-09, 06:42 PM
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Originally Posted by ecman51`
I'd also check the stat and it's wiring, to rule that out. Disconnect W wire from low volt terminal strip in furnace to see if that stops it. If so, stat or wire shorting sporadically. If not, relay likely, that changes the 24 volt signal to 120 to the inducer.


Heh, heh! I'm not convinced I believe in ghosts...


But the check seems you describe seems worthwhile. I think what I'd do is to leave everything the way it is and when the inducer motor switches on mysteriously, check to see if there is 24 VAC at the W connection when the thermostat is off. If that condition is detected, then I'd disconnect the thermostat lead to W and check for voltage (1) at the W terminal of the circuit board and (2) on the thermostat wire just disconnected. Also, if the voltage is detected on the thermostat wire, I'd connect the wire to W a few times to verify that it is what is causing the inducer to turn on.

Leaving the wire disconnected and waiting a while to verify that the inducer doesn't turn on if the thermostat wire is disconnected would be another double check.

I wonder if the thermostat could be turning on erratically for some reason? The tests above would help identify that if indeed it's happening.



Good idea!
 
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Old 01-05-09, 06:55 PM
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Goodman Draft Inducer keeps cycling

Originally Posted by SeattlePioneer
Heh, heh! I'm not convinced I believe in ghosts...


But the check seems you describe seems worthwhile. I think what I'd do is to leave everything the way it is and when the inducer motor switches on mysteriously, check to see if there is 24 VAC at the W connection when the thermostat is off. If that condition is detected, then I'd disconnect the thermostat lead to W and check for voltage (1) at the W terminal of the circuit board and (2) on the thermostat wire just disconnected. Also, if the voltage is detected on the thermostat wire, I'd connect the wire to W a few times to verify that it is what is causing the inducer to turn on.

Leaving the wire disconnected and waiting a while to verify that the inducer doesn't turn on if the thermostat wire is disconnected would be another double check.

I wonder if the thermostat could be turning on erratically for some reason? The tests above would help identify that if indeed it's happening.



Good idea!
I will perform this check tomorrow, hopefully it will stop raining by then (maybe ice by then they say). I can tell you that the thermostat (Hunter Digital) does not give any idication on its control panel that it is calling for heat (not a voltage check, just no clicking/blinking/etc).

----Walt
 
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Old 01-06-09, 10:26 AM
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After you have worked on furnaces for the years, like I have, I do not bother to over theorize and get hung up on what may or may not be, since many checks can be made very rapidly(often in seconds) with a multimeter, and it costs you nothing. Different manufacturers can do things slightly different.
 
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Old 01-06-09, 12:49 PM
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Originally Posted by WaltJohnson
I will perform this check tomorrow, hopefully it will stop raining by then (maybe ice by then they say). I can tell you that the thermostat (Hunter Digital) does not give any idication on its control panel that it is calling for heat (not a voltage check, just no clicking/blinking/etc).

----Walt

That would be common. If the thermostat is calling for heat the "W" contact at the furnace would normally have 24 VAC energizing it.

Disconnecting the thermostat wire is a way of isolating the furnace from the thermostat. If the thermostat wires or disconnected and the inducer motor still starts up, you know the thermostat isn't the cause!

But until you check, it could be the explanation.


Lots of furnace repairs involve rather common problems, easily diagnosed. Then there are a limitless number of oddball problems that can be caused by very unusual conditions.

Unraveling those is what takes skill, some imagination and the ingenuity to think of possible causes and ways to test to see if those causes could be the actual problem.
 
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Old 01-06-09, 01:28 PM
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Originally Posted by SeattlePioneer
Then there are a limitless number of oddball problems that can be caused by very unusual conditions.
Here's one for you:

Late last heating season I finally had to pull the burner assembly out to see what might be going on, and found a hole in it that reeked havoc on the flame coming out the end of it. This then affected the flame sensor, making the furnace shut down.
 
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Old 03-06-13, 08:48 AM
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Walt,
Did you ever figure this out? I'm having the same issue...
Thanks,
John
 
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Old 03-06-13, 12:41 PM
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Welcome to the forums. Since this thread is four years old, you really need to start a fresh thread of your own.
 
 

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