Sounds like either the flame sensor is not working.
The sequence for starting the furnace is:
1. extraction fan on
2. pressure sensor (for fan)
3. ignitor (spark or glow plug) comes on
4. gas valve opens up
5. ignition of flame
6. flame sensor (or temperature sensor)
7. plenum temp. sensor
8. main fan starts
It is most likely that the flame sensor is dirty or gone,
or (and I hope not), the module is gone and needs to
be replaced.
SOURCE: No heat, trouble shooting light has continious flash.
There is a vacuum sensor on most units tied from the exhaust gas fan to the sensor. Does the unit try to start? If the unit's exhaust fails to pull the switch it will turn off after about 30-45 sec after starting. "IT" thinks it's not exhausting and stops to keep from overheating. Do you have this exhaust fan and rubber hose to sensor? Can you see if that fan is turning on start?
SOURCE: Goodman GMS90904CXA Wont ignite, light blinks 3 times
Ok, you either have a inducer fan issue or a pressure switch issue or a plugged vent pipe. The inducer turns on to establish a draft for the exhaust. If it is not working you will get this error code. If the pressure switch does not sense pressure caused by the inducer, it will give this code. If either the intake pipe or exhaust pipe is blocked (even y just a little) it will give you the same error code. If the condensate hose or receptical is plugged, again it will give you this error code. Good Luck!
SOURCE: I have a goodman gmpn 100-4 REVB furnace that will not stay lit
If the igniter lights the burners the ignitor..... is not bad. Its like a light bulb.... it works or ot doesn't.
You are describing a dirty flame sensor. Dishonest contractors will sell you a new ignitor but clean the flame sensor when the are installing the ignitor. It is located at the opposite end of the burners than the ignitor. It has one wire going to it. Remove it and clean the rod with a piece of fine grit sandpaper. this should be done every year before heating season.
Good luck
SOURCE: I had a friend install my new Goodman GMH950704CX
The most common mistake on these after installation is not flipping the switch on the gas valve from 'off' to "On". Remove the top panel and in the middle of the cabinet the gas line comes into an aluminum looking device. There is a switch on top. If that is on, ensure that the gas has been turned back on.
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