goodman fan always on

[ericoud]

I have a 2002? Goodman Gas Furnace, model:GMNT120-5

The blower (fan) runs constantly, even if the t-stat is off/heat/cool or is set to on/auto.

I pulled the cover and everything appears fine, nothing burnt or damaged, the cabnit is clean. Fuse is good, and the trouble shoot LED is on indicating normal operation(per the manual).

To rule out a short in the Green 24v wire I unhooked it and swapped out a with another and the fan still comes on.

Sitting in front of the control pannel with everything hooked up and power on.. I can press the door switch and the LED will light up and the cap will begin to energize, when the cap is energized the relay will trip and the fan will come on. If I unhook the green(fan) wire this doesn't happen.

I've changed the t-stat (wanted a new programable anyway, so that's ruled out also).

Also wanted to say that the heat does work, if I dial the t-stat above room temp and set the t-stat to heat, the burner lights and heats the house to temp, then shuts off(but the fan stays on).

At this point I'm guessing a new control board?

Thanks for any help.

Eric.

[Stormin Mormon]

That, or fan limit switches. I don't know off hand if Goodman uses the Honeywell style limit switches.

[Bubba]

Replace the thermostat again, first. Lots of bad new thermostats out there. Its almost always the thermostat. If that doesnt do it, its positively the control board. Good luck, Bubba

[Noon-Air]

Ummm..... nope. Care to guess again??

[Al Moran]

The simple fix is to just keep throwing parts at it till you fix it. That will be 99.99 please.

[Murdentech]

Lift 24 volt red from the board, press the switch. If the fan still comes on, check the motor leads to the board, make sure you don't have a board with a port for continuous fan. You should have one motor lead to common (white), one to the heat port and one to the cool port. If the fan still runs, you probably have a bad board or a shorted wire between the motor leads and something else.

[Stormin Mormon]

Maybe they have a trained pigeon who says "bleepers, it's getting hot in here" and then pecks the switch.

[RSCamaro]

Sounds like you have issues with the thermostat to me.

...Ron

--

68'RS Camaro 88'Formula 00'GT Mustang

[Zephyr]

I like Bubba's suggestion.

[Tekkie®]

Al Moran posted for all of us...

Gee Al, how come he gets a 50 bux discount?

[Al Moran]

He gets the moron discount.