ReplyI 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?
Regular Guest
Goodman Furnace
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.
Professional Member*
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?
Professional Member*
Check for faulty pressure switch, tubing or nipple on inducer plugged. Sometimes if pressure switch cycles rapidly that will happen.
Regular Guest
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.
Professional Member*
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.
it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair
Professional Member
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.
Professional Member*
that is good advise......Originally Posted by local 392
it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair
Regular Guest
[www.youtube.com/watch?v=FwOu3Kzq1Aw
heres a video of the furnace in action
Professional Member
I agree with Carmon. I think you have a faulty board.
First child on the way and
"It's safe to say that I'm gonna get my payback if he's/she's anything like me"
Professional Member*
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.
Professional Member
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...
Last edited by Andr00; 12-28-2012 at 10:46 PM.
Regular Guest
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.
Professional Member*
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.
Professional Member
Oh sorry I had to reread your first post. Didn't realize the board was new
First child on the way and
"It's safe to say that I'm gonna get my payback if he's/she's anything like me"
Professional Member
Is the board powered directly from the disconnect or is it powered from stack-ons on the transformer?
First child on the way and
"It's safe to say that I'm gonna get my payback if he's/she's anything like me"
Regular Guest
directly from the disconnect. I have change the stake ons that connect to the board
Professional Member*
check all the Molenex plugs, sometimes the wires are not installed (pushed in) all the way
grip the plug or socket an push each individual wire in as far as it will go.
But from your Video it sounds like a bad relay on the board
Why am I the only naked person at this gender reveal party
Professional Member
Sounds like a bad board to me as well.
The relay that feeds the draft motor keeps dropping out.
Professional Member*
Have you confirmed a steady call for "W" from the thermostat? It could be the stat dropping a call.
But that doesn't explain why the LED goes out. It should be lit any time 24 volts are present. Is there float switch somewhere in the low voltage circuit? I've seem a malfunctioning float switch cause some erratic behavior.
Odd issue. Please let us know the outcome.
Professional Member
Try jumping out inducer so it runs all the time. Then see if burner goes thru normal cycle. Also try taking inducer off board all together than jumping out pressure switch. Make sure gas is off. You will be able to see if unit goes thru cycle this way as well. This should be able to narrow down the problem.
Posting Permissions