blower motor not turning off after cycle, Goodman furnace


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Old 01-28-09, 02:49 PM
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blower motor not turning off after cycle, Goodman furnace

Hi,

I have a Goodman furnace that is 15 years old. Model GMP050-3, Serial 940400-6652. It is propane. The thermostat is a ritetemp analog model 6010.

Here is the blow by blow:

Select heat, top lever positioned on heat, bottom (fan) lever on auto. After 30 seconds, venter motor goes on. after 15 seconds, hot surface ignitor goes on. Gas fires on after 5 seconds. after 30 seconds, main blower motor goes on and moves air. House reaches temp. Thermostat turns off. (clicks off) Flame turns off but main blower and venter motor stays on and do not turn off. Continues to run. Both motors are on for more than an hour. I turned the t-stat off. Top lever to off, fan lever left alone to auto. Fans go off eventually. They used to go off after about 2 mins.

Checking the furnace: Looked at control board, no flashing of LED, stays on continuously. Both motors are still on. I remove the panels and the motors turn off. I believe the service switch cuts the power. I push the service switch in (plunger type) and the LED comes on the control board. The fans, both venter and main blower do not come on at this point. I put the panels back on and wait. After 15 mins, both blower and venter motors come on at the same time. (t-stat still off) Sometimes they turn off but mostly I have to unplug the cord (115vac) or open the panels. As i'm typing this to you, the motors have just turned back on. The LED is on continuously with no codes flashing.

I'm trying to save some money here, does anyone have a fix they can walk me through? Or has someone had similar issues that they can tell me. Oh, motors just went off! Seems to be cycling. O.K. new problem, about every 15 mins, the blower motor will kick on. After about one min the venter motor will go on. Both motors on. Now the LED flashes five times. Then venter motor will turn off about 5 mins later, LED flashes 1 time, then blower motor will turn off in 15 mins. LED stays on. Seems to repeat. Help!! It's driving me nuts.

Thanks for the advice.
 

Last edited by sdelectrician; 01-28-09 at 03:34 PM.
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Old 01-28-09, 04:16 PM
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Error codes

Somewhere on the furnace, probably inside the blower door, should be a list of what that blink code means. That model is notorious for boards going wacky.
 
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Old 01-28-09, 04:21 PM
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Did this problem crop up out of the blue without anyone else doing any work to the furnace or thermostat?
 
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Old 01-28-09, 04:38 PM
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Erratic operation as described strongly suggests a bad circuit board to me.
 
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Old 01-28-09, 04:50 PM
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Wacky happenings to goodman gmp050-3

Hi guys, thanks for answering.

There are no codes listed on the service doors. Could they be somewhere else? Furnace is laying down, not upright and is in the attic. The only place I found codes was from a website. ICM controls. They have a replacement control board. The instruction sheet with the item has the codes.

ICM280 REPLACEMENT BOARD
1 flash = ignition failure (3 tries and lockout)
2 flashes = pressure switch stuck closed
3 flashes = pressure switch failed to close
4 flashes = limit switch failed open
5 flashes = flame present with gas valve output off
6 flashes = brownout voltage
7 flashes = fault twinning
rapid flashing = wrong polarity on transformer (24v)

The blower and venter motors seem to cycle on and off every 15 mins. The blower will come on first then the venter, they will stay on for several mins, then the venter will shut off, then the blower will shut off some mins later. When this cycle happens, the LED will flash once and then 5 times. When motors turn off eventually, the LED stays on and does not flash anymore. Weird huh? Maybe it's possessed.

I have uplugged the unit. Can you help me diagnose and fix it or should I call the tech? Priest? Trying to save money but I'm not foolish.

Thanks.
 
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Old 01-28-09, 05:20 PM
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Hi ecman51,

This problem started to show up the week of Christmas 2008. It has gotten progressively worse each day. There has been no work done prior. This is the first problem in 15 years.
 
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Old 01-28-09, 06:12 PM
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If the flame shuts off with the stoppage of the call for heat and yet the vent motor and blower run on for like an hour, some relay is stuck - and those relays are usually on the board. So as Grady and SP have stated already, the board is likely defective.

After 15 mins, both blower and venter motors come on at the same time. (t-stat still off)
And this also shows not only something perhaps wanting to stay stuck, but perhaps being weak. A weak relay that is allowing the 24 volt signal to want to open up the 120 volt signal when it is not ready to do so.
 
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Old 01-28-09, 07:17 PM
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Hey ecman,
I will order a control board and swap it out. I do hear the relays on the board energizing and de-energizing so I think you guys probably nailed it thanks. If it works it will save me a bunch. Rates for labor and parts are rich out here in Cali.
 
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Old 01-31-09, 01:19 PM
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Update on problem with Goodman Furnace

Hi all,

I purchased a new control board and that did the trick. Thanks for all the advice. It saved me $300.00 to do this myself and I am grateful. I will do regular maintenance to my unit from now on. I'm sure I will be back to pick the experts brains here. This forum rocks! I'm glad to have found it.
 
 

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