goodman wont fire


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Old 02-28-09, 03:58 PM
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Question goodman wont fire

i have a goodman gmh950703bx. the flame ignitor wont fire. i put my voltage tester on it and check for continuity and it was fine. theres no flashing light. the light is on red. the inducer motor will start up and run for less than 5 seconds and quit. then will start again over and over.
 
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Old 02-28-09, 04:16 PM
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I have never ran into that particular of an oddity.

If I did, I would first check to make sure there is not something amiss with stat or loose stat wiring connection, killing the inducer. Make sure terminal W to chassis ground is still 24 volts (test this in the furnace)as the inducer shuts down. IF you lose 24 volts on the test, then you have something wrong with stat or the wiring associated with stat. The inducer needs to run for many more seconds than 5.

If the 24 volts remains, yet inducer shuts down, see if 120 volts to inducer is shutting down or not. If it is, sounds like weak relay. If current IS there, then something wrong with motor.
 
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Old 02-28-09, 04:21 PM
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Does solid red led =power to board no call for heat?
Sounds like the furnace is not proving on the pressure switch.
Check the flue for trash or water.
Check the condensate trap for the flue
Check the pressure hose for the pressure switch
Check limits on the furnace

you are losing 24v somewhere.....
 
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Old 02-28-09, 05:00 PM
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ok... i checked the flue and it was clear. i jumpered the pressure switch coming off the inducer motor and it fired up. then trouble code for pressure switch stuck open. i plugged the pressure switch back in and the unit is operating. bad pressure switch?/// should i get a new one monday or think its something causing it?
 
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Old 02-28-09, 06:10 PM
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90% of the time, a pressure switch isn't opening for a reason ---the furnace or vent is obstructed in some way.

The other 10% of the time, the pressure switch is bad.

A competent repairman will measure the pressure on the pressure switch to determine which of the se possible problems is occurring.

The marginally competent repairman usually assumes the pressure switch is bad and replaces it, and then 90% of the time discovers the problem continues.

You really need a competent repairman to analyze and correct this kind of problem for you. Guessing and supposing aren't adequate diagnostic methods, and an inexperienced person isn't competent to inspect a furnace for the various kinds of problems that can be plugging up the equipment.
 
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Old 02-28-09, 07:43 PM
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Congratulations, you have a very good furnace. Contrary to many opinions, I think the GMH950 is the best value out there. There are two things that come to mind here. 1) make sure the exhaust is pitched slightly back to the furnace with no sags or low spots. 2) take off the top cover and check the two drain hoses. Make sure there are no sags or low spots and they slope down to the trap. Then make sure the drains are not backed up. The pressure switch in this furnace is sensitive. Thats a good thing for you and your family.
 
 

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