I have a goodman gmp125-4. The heater comes on the furnace fires up with all the burners on and it shuts off after maybe 5-6 minutes and then the module light blinks 4 times. Are there any solutions for...
You have a serious problem. That is the primary limit overload in the heat exchanger. Either your gas pressure is too high...checked with a manometer should be 3.5" w.c. for Natural gas and 10" w.c. for LP, or your air speed is too slow. If you have a restriction in the duct, even dirty filter, your fan speed will slow causing the temp rise from return to supply air to rise. The unit data plate has the temp rise range on it...for that unit it is probably 45-75 or close thereabouts. you should check the air temps a couple of feet from the unit on the return and supply duct. If the data plate shows 75, or whatever, your actual temp rise should be 10 degrees below the max on the data plate or in that case 65 higher. This unit has a three speed motor, if Black from the motor is not on the heat terminal of the control board,start there. With power off, put the black wire on the heat stake on on the board. If it is already on the cool spade, you can make a jumper and use that same speed for both heat and cooling. After this is done, recheck the temp rise on the air and see if you get about 10 below the max on that temp rise data.
If the temp rise looks good, be very careful in doing this; with power off, remove the primary limit, which is the one going into the exchanger, and either temporarily jump out those two wires or just set it aside still hooked up so the wires dont touch anything and with a temp probe or thermometer stick in the hole where the limit goes, start the unit and check the temp at that spot. That limit is 210 degrees. If it is rising higher than that and you are sure the temp rise is good, you probably have crack in the heat exchanger shooting hot air in that area close to the limit.
Hope that helps.
Jan 05, 2010 |
Goodman GDS80904BNA Open Flame Heater