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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 899
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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House fan runs but av won't kick on. I reset the breaker and

Customer Question

House fan runs but av won't kick on. I reset the breaker and it kicks on and blows cool but kicks of after a minute or two. House fan continues to run.
Submitted: 1 year ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 1 year ago.

Hi I'm Brian and I'm here to help!

This points to one of a few things but the most common of them being that the run capacitor in the ac unit is weak or has failed. Other possibilities are: a loose or burned wiring connection in the unit or at the breaker(s), a failed starting capacitor or relay (if equipped) or a failing compressor that is seizing up. I would look at and tighten all wiring connections in the unit and the power branch circuit going to the unit. Then I'd replace the compressor run capacitor. Chances are those things will take care of the problem.

Please reply if you have further questions about this. Otherwise, please remember to rate positively (3 stars or better) before you leave! Bonuses are welcome and very appreciated!

Thank you,
Brian

Customer: replied 1 year ago.
I had a guy come and replace the compacitor last summer and I don't see any loose or broken/burnt wires. It just kicked on and is running fine now. It's been doing this for a couple days now. It starts working fine when the sun goes down and starts cooling off outside.
Expert:  Brian HVAC Guy replied 1 year ago.

It sounds like it's right on the edge of tripping the breaker or heating up and shutting the compressor down. One of the two. When it cools off and there isn't any solar load and the ambient temperature drops, the amp draw of the compressor and the high side refrigerant pressure both drop. That is why it continues to run at night. Still sounds like a loose wire connection. Sometimes they're not visible, you need to tighten all connections including the breaker connections and connections in the disconnect on the wall by the ac unit. There's also a chance the condenser coil is dirty enough to cause this issue and it only shows up during the heat of the day with a solar load as well. Clean the condenser coil with simple green and a garden hose. Tighten the breaker connections and any wire nutted power connections. Double check that the larger of the two refrigerant lines is beer can cold while the unit is cooling. That should do it!

Please reply if you have further questions about this. Otherwise, please remember to rate positively (3 stars or better) before you leave! Bonuses are welcome and very appreciated!

Thank you,
Brian