Nothing Happens; Chapter2

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  #1  
Old 11-15-07, 07:04 AM
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Nothing Happens; Chapter2

New thread on an old subject w/ similar title. After a lengthy debug, my Goodman GMP100-3 was completely dead. Solid LED, no fault code, no blower ops, etc, all switches, tranformer, etc checked out OK.. only thing left was circuit board.

So, swapped in new board last night. Result= I can now turn the blower on, but it never tries to ignite. The LED is now a continous flash... I think it means an incorrect twinning, incorrect primary polarity... Either way, what do I check? I think I am getting close to solving this, but I need more expert advice.

Thanks -
 
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  #2  
Old 11-15-07, 08:46 AM
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Hi plh:

Are you sure the R and C terminal wires are the same as on the old board? Also, are you sure that the hot wire [black] goes to hot and the neutral [white] goes to neutral? If yes, then try reversing the transformer primary wires. IOW- the high voltage leads [hot & neutral wires going to the transformer]. If the transformer secondary wires [the 24 volts side] are the same as before, reversing them might cause a thermostat problem.
 
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Old 11-15-07, 07:21 PM
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Polarity

Disconnect the main power wires going into the furnace. Keep them apart & don't allow them to touch anything. Turn the power back on & check each one to ground. If the white shows +/- 120 volts & the black little or no voltage, the polarity is reversed. You really should find out where the mix up occured (switch, junction box, maybe even at the panel) & correct it, but, you could just hook the incoming white to the furnace black & vice versa. Also make sure the furnace has a ground wire going all the way back to the panel ground.
 
  #4  
Old 11-19-07, 03:47 PM
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Wits END

OK, I reversed polarity everywhere & still this dadgum board keeps a continous flashing LED. The blower runs ok. Could I have gotten a bad board from the supply house?? I think every rock has been turned & still the same result.

Again, the orig board was completely dead... steady state LED, but nothing worked...blower, etc. All switches, etc check ok

Before throwing this piece of "stuff" in the dumpster, what else could it be????? I know goodmans are/can be junk, but I just need a little heat for the barn for petes sake.
 
  #5  
Old 11-19-07, 05:23 PM
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The Goodman I worked on about 3 hours ago had a fan that was coming off the inducer motor shaft and pinned to the inside of the housing preventing the ventor from coming on and hence nothing at all would work; nothing. The inducer only took me maybe 2-3 minutes to remove (3 screws, 4 wires, exhaust pvc, pressure switch vacuum tube and condensate drain tube. Remove, turn it around, take out maybe 10? 1/4 inch hex screws, pull the two halves of the inducer housing apart.

They will not sell just a new fan for Goodman due to liability reasons. The liability involves that if the mating halves get compromised, exhaust gases could be forced out the seam. The saftey switches would not pick that up. Large supplier in town wanted $100 for whole new unit.

Since my seam was still real good with the factory rubber lining in the groove, I used tiny stainless band clamp to resecure and center the fanblade. May not last forever but......Better than a 2-part epoxy attempt I previously tried.

Actually you can find out if that is your problem (seized up inducer) by - when the motor resets- you should get a motor hum briefly until it kicks out again (silent). But if in doubt, the ease at which to get to the rear of the unit to see/look, and try to spin the blade to find out if the fan blade is seized, or motor seized. No need to take the inducer apart, at this investigative stage, as there is enough room around the center (a couple inches) so you can find out.
 
  #6  
Old 11-20-07, 11:39 AM
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You didn't reverse polarity at 2 places did you? That would put you back at square one. You only needed one reversal.
 
  #7  
Old 12-28-08, 08:49 AM
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did you ever get your twining error resolved, I have a york doing the same thing,when I replace the old bad board with a new replacement board. Its funny everything works except the fan on the old board and the fan comes on to soon on the new board not allowing anything else (IE burners) to come on.
any help would be appreciated
jim
 
  #8  
Old 12-28-08, 11:45 AM
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Could you please just start over and say what YOUR problem is? Give us some time frames of when things went wrong and what you did to try to correct. Also tell us how the furnace sequences. Sometimes problems that one thinks are related to some other poster may not always be.
 
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