Goodman Furnace

[jledford382]

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.

Oh sorry I had to reread your first post. Didn't realize the board was new

[jledford382]

Is the board powered directly from the disconnect or is it powered from stack-ons on the transformer?

[evilsanta]

directly from the disconnect. I have change the stake ons that connect to the board

[jmac00]

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

[filiberto]

Sounds like a bad board to me as well.
The relay that feeds the draft motor keeps dropping out.

[Brent Ridley]

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.

[terpfan_]

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.

[Mr Bill]

Had a Coleman doing this exact same thing about a month ago, bout kicked my butt, finally after 1.5 hrs of troubleshooting, I noticed were the installers use the on board transformer to also power the zoning, I pulled the power leads off the transformer to the zoning box and and it worked like brand new. I don't see how the system lasted 2 years before it finally started acting up wired this way, maybe one of the zoning motors started drawing a little more or was going bad, and stressed the 40va transformer more. I stuck a new 80va on there for the zoning and have not heard a peep back.

[Joehvac25]

I had one last week that would work fine If I jiggled the molex but once It shut down it would keep throwing a ps switch code eventhough inducer never ran, then jiggle again and it would run, new board fixed it.

[Mr Bill]

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.

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.

If this unit is "around" 5 years old, the board should still be in warranty, and the HO should not be buying any boards period. Most mfg. have a 6 month install grace period. If it were a Ruud I could warranty the board all the way to 5.5 years, and would if the customer was nice to me.

[evilsanta]

Went back this morning and began trouble shooting at ground zero. Found that the pressure was acting up. Started the furnace and the problem began immediately. Let the inducer run for a sec and jumped the pressure switch and it ran fine. I tested it time and time again with and with out the jumper and had the same result 20 out of 20 times. Changed the pressure switch and tube. The board never coded the entire time with the failure. Thanks for the incite. To add Mr. Bill the customer never once purchased any parts, there was another company involved prior who I work for. The unit was out of warranty besides the heat exchanger.

[mrlighturfire]

I had GOODMAN call same thng ended up being bad pressure switch

[hurtinhvac]

I've known pressure switches to drop in and out so quickly so as not to be caught by the board, resulting in no errors while stopping the cycle. But normally the inducer keeps on trucking with pressure switch errors, whether the board cataches them or not...?

Another idiosyncrasy we'll all be expected to remember, I suppose. I was tipping towards the board as well. Sometimes I think I should just jump all safeties one at a time when I get these weird ones, even thought it doesn't jive with what you are thinking as far as the normal sequence of operation. How long would it take? Few roll outs, a limit, draft switch, pressure switches...?