Furnace blowing cold air Resolved.
Furnace blowing cold air resolved 1/29/2026 McDonough, GA Aaac service heating and air received a call for no heat 1/29/26. The furnace was blowing cool air . It was heating earlier but stopped. There is a code flashing on the circuit board. It can be seen through the sight window. The label on the door say 33 lockout. The furnace main limit has tripped due to excess heat. It turns on the blower and the flames off. Do not reset the furnace before fixing the issue. The fan motor was spinning too slow allowing to much heat to remain in the furnace . The capacitor tested 3.8 but should be 7.5. This is not the only thing that will cause a lockout, today it was the issue. The motor was tested and is good. After replacing the cap the issue was solved. Check for a dirty filter and/or closed vents. These can put a strain on the motor and capacitor. You must put the right size capacitor back in. If you don't know the size it is on the label of the motor. Th...