Furnace Run Then Abruptly Stops

[BUDMAN]

My Goodman (GMS9) gas fired warm air furnace comes on fine--the igniter, the burners, etc. A few seconds of warm air comes thru the registries then the furnace shuts down--it tries to come back on but nothing ignites and it then just winds down. It will do this as long as its allowed to.

If its turned off and sits for a while and is turned back on it will ignite and go thru the whole process and, like mentioned before, a little warm air comes out before shut down.

Any suggestions would be appreciated.

[BADCUDA]

I feel your pain !!! My "Goodman" has left my house cold many times. First thing to check is the circuit board down by the fan. It blinks codes. The codes are on the inside of the bottom door. If that isn't it, clean the probe that extends into the burner on the right side. It gets corroded. Next would come the high limit switch. I've gone thru 3 of them now. Check that stuff first. Good luck.

[LazyPup]

The problem you describe is indictative of a restricted air flow..First check the filter, then chech the return air grilles to see if they are obstructed by furnishings or personal belongings.

[BUDMAN]

The LED blinks 4 times and the inside panel says it is a high limit switch. Any further suggestions?

[BADCUDA]

Exactly what mine did. To test, pull both red leads from high limit switch and connect together. Start furnace and everything should cycle fine. Do not run the furnace like this for an extended period of time. That switch is there for a reason. Buy a six-pack of these switches because they are junk at best. Good luck.

[LazyPup]

The code is telling you it is the high limit switch that is tripping out, but that does not mean the high limit is malfuncioning. If you have a restricted air flow the air in the plenum is getting too hot and causing the high limit to trip out. As i stated before, step one is to check for dirty filters, then check return air grilles to make sure they are not obstructed. Step three is to check the fan motor and blower wheel to insure they are working correctly. The last step is the high limit switch.

[BUDMAN]

Thanks for walking me thru this guys. I'm at step three now--how do I check the fan motor and blower wheel to insure they are working correctly. If everything is o.k. at step three, I'll move on to the limit switch.

[BUDMAN]

Hi everyone--I still need assistance. How do I check the fan motor and blower wheel to insure they are working correctly. Any suggestions will be appreciated.

[imeduc]

Turn the tstat to fan on if it dont run give the blower wheel a spin and see if it runs then

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