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My name is Billy. The unit is firing up...but it is overheating and shutting down....cools...heats ...shuts down...then after 5 times of doing this it locks out into fan only and exhaust motor only and runs that way for 3 hrs...or until power cut and restored.
It could be filters, bad belt (if equipped), motor faulting....pretty much anything that restricts air flow.
And if the limit switch is sticking it will not matter about reset..
Have you checked filters, belts, blower motor? And sometimes the ac coil gets plugged
The motor in question would be the circulation blower fan. Let me see if I have a pic for you...just a moment
Ok this unit has no belt and is a direct drive.
So I would check the motor in heat mode and make sure it is running.
Check blower wheel for debris
Check ac coil (behind air filters in unit) to make sure not dirty
Then note ...was any construction done during the last year?
Excessive drywall or dust?
Were any walls modified/duct?
Your sole point will be to check airflow through the unit from the blower itself running to having fins, coil and filters
How about speeding the blower up? According to the diagram in the manual I sent you there is another higher speed available for heating.
there are different color wires from the blower motor. Depending how you hook up and the color you use changes the blower speed.
See the red square HERE
If you want to post a pic of the motor and wires I could direct further.
It could be anywhere ...especially where duct passes through walls. There is a damper held open with a link that melts in high temps....however these links can fail under vibration and age and the damper closes.
They can be any size but here is a pic of one click here