Solid Red on Goodman Furnace (for about 1 sec) then Nothing
#1
04-05-17, 04:28 PM
Solid Red on Goodman Furnace (for about 1 sec) then Nothing
Model: GMP075-3 (manufactured 1993, installed 1996)
Behavior: When powered on with the door safety switch engaged and with a jumper from R to W on the board (to bypass the thermostat and wiring to the stat) the furnace comes on for a split second, spinning the inducer motor briefly and then the red status light and all activity shuts off.
Tests: Voltage from R on the board to ground is 28VAC / with a jumper from R to G on the board the blower exhibits the same symptoms, on for a second and then off / voltage at the inducer motor is only 79VAC (on my other working furnace it is 123VAC when running)
My guess is a bad board, but wondering if there is anything else I should test first?
Behavior: When powered on with the door safety switch engaged and with a jumper from R to W on the board (to bypass the thermostat and wiring to the stat) the furnace comes on for a split second, spinning the inducer motor briefly and then the red status light and all activity shuts off.
Tests: Voltage from R on the board to ground is 28VAC / with a jumper from R to G on the board the blower exhibits the same symptoms, on for a second and then off / voltage at the inducer motor is only 79VAC (on my other working furnace it is 123VAC when running)
My guess is a bad board, but wondering if there is anything else I should test first?
#2
04-05-17, 05:20 PM
Member
Make sure you have 120 volts at the board. Unplug and re-plug all the connectors and terminals and look for corroded contacts. Look at the back of the board for any obvious bad solder connections. Try temporarily jumping across the door switch to rule it out.
#3
04-05-17, 09:03 PM
Thanks for the reply. There is 120VAC at the board (at the BLK L2 terminal). I checked all the connections and there was no sign of corrosion. Also, all the solders looked solid on the backside of the board.
When I switched on the power, I had one instance where the inducer motor stayed on for about 5 seconds before everything turned off (red light included). All other times either nothing came on or it came on for a split second.
I can hear a relay on the board trip on and off when this happens. Long story short, it's behaving the same after these checks.
When I switched on the power, I had one instance where the inducer motor stayed on for about 5 seconds before everything turned off (red light included). All other times either nothing came on or it came on for a split second.
I can hear a relay on the board trip on and off when this happens. Long story short, it's behaving the same after these checks.
#4
04-05-17, 09:13 PM
One other thing to note: for the 1-5 seconds that the inducer motor runs, the voltage at the motor is 120VAC. As soon as the red light shuts off, the voltage drops to around 79VAC.
#5
04-06-17, 06:39 AM
Member
If you are using a digital meter you may just be reading stray voltage.
After the inducer runs and the pressure switch is made, the next thing that happens is the hot surface ignitor is turned on. It normally takes more than a couple seconds to get to that point, but I guess it's worth checking the HSI for a short to ground. Or just disconnect the HSI from the board and see if the furnace gets any further in the start up cycle.
Did you jumper out the door switch? A flaky switch is fairly common.
After the inducer runs and the pressure switch is made, the next thing that happens is the hot surface ignitor is turned on. It normally takes more than a couple seconds to get to that point, but I guess it's worth checking the HSI for a short to ground. Or just disconnect the HSI from the board and see if the furnace gets any further in the start up cycle.
Did you jumper out the door switch? A flaky switch is fairly common.
#7
04-06-17, 09:17 PM
Just jumped out the door switch: same behavior. Also detached the hot surface ignitor from the board: same behavior. Just for good measure, I detached, checked and reattached all the connectors again: same behavior.
I see a replacement board on Amazon for $65, is it time or is there more that I can try?
I see a replacement board on Amazon for $65, is it time or is there more that I can try?
#9
04-14-17, 03:20 PM
FINAL UPDATE: It's working again
I order a replacement control board from Amazon (ICM280 by ICM Controls), installed it and the furnace is working again. Thanks all for your help. The replacement board included good step-by-step instructions and the install was quite easy.
