Goodman Furnace

[evilsanta]

So I have furnace that has finally beat me. Its a Goodman 80% about 5 yr old. The problem came to me after another company had replaced the board and by-passed the on/off switch on the unit. The actual problem is that the furnace will begin running the inducer and shut down as if the power was shutting on and off. I had suspicion right away that the blower door switch was bad cause it was stuck closed and didnt open when I removed the door. I bypassed the switch and the problem still happened. I kept checking voltage to the unit while it was acting up. I never saw a voltage drop. I bypassed the thermostat and the problem kept coming. I also kept checking the transformer to see if it was acting up and never lost the 24v. If anyone can offer a suggestion to this issue it would be greatly appreciated. This problem is intermittent.

[OldSchoolMech]

I would start back at the panel and check the feed etc.
Why was the power safety switch Removed? I would check thier joint's made in the wire.
look for loose conections.

Or is it the preasure switch holding it out whats the code on the board?

[billg]

Check for faulty pressure switch, tubing or nipple on inducer plugged. Sometimes if pressure switch cycles rapidly that will happen.

[evilsanta]

The furnace is not coding at all. Its like someone is shutting it on and off. All the lights on the board shut off for a moment and it will continually do this then just stop and run. I bypassed the safety switch temporarily during trouble shooting the switch did not move freely and I thought maybe the contact was shot. I did replace it at the time off the call. I did check the power on the panel, switch and board. I have 118 everywhere and it never drops out.

[carmon]

hate to say it may be the board....one tried to beat me yesterday ...same problem..... board fixed it..... also had one a while ago with a bad neutral.... if you have 118 and it never drops then power not the problem..... could be the ventor motor is there line voltage there or do you loose it.

[local 392]

When checking voltage, use the neutral at the board. Sometimes we don't think and just hook to the cabinet, and find out later that the problem was in the neutral all along. Also I would check outputs on the board, are you loosing power to the motor? I have seen boards come from the factory with bad connections.

[carmon]

When checking voltage, use the neutral at the board. Sometimes we don't think and just hook to the cabinet, and find out later that the problem was in the neutral all along. Also I would check outputs on the board, are you loosing power to the motor? I have seen boards come from the factory with bad connections.

that is good advise......

[evilsanta]

[www.youtube.com/watch?v=FwOu3Kzq1Aw

heres a video of the furnace in action

[jledford382]

I agree with Carmon. I think you have a faulty board.

[54regcab]

Check the power from +24v going from the board to the thermostat. The relay kicking on and off is odd, the board very well could be the problem.

[Andr00]

I had a similarly aged Goodman 80% doing the same thing a while back. The board was dropping out power to the inducer then starting it back up. Same clickety relay too.

The new board that Johnstone gave me was completely different from the old one. I suspect the redesign of it was no coincidence...

[evilsanta]

I really would hate to sell this guy a board when the board thats in there is only one week old. The home owner has the original board that the last service company changed out and said that the old board did the same exact thing.

[socotech]

I had one do this to me and ended up being combustion motor. It was also an 80% Goodman. It was a lot older than five years though. I would check to see if you are losing 115v at combustion motor power leads.