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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 7997
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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My AC outside unit won't shut off. It cools the house OK.

Customer Question

My AC outside unit won't shut off. It cools the house OK. Turned off all 3 thermostats, unit continued to run. Contactor was engaged. I turned off the furnace at the main and the contactor disengaged. I pushed in on the contactor and electrical spark burned wire apart from the power source. I just want the AC unit to stop running continuously and icing up.
Submitted: 10 months ago.
Category: HVAC
Expert:  Phil replied 10 months ago.

Hello, so far it sounds like the contacts in the contactor are fused (burned closed)... the solution is to replace the contractor, but in doing so it is *crucial that you do not get the 24 volt control coil wire confused with the 230 volts and wire it incorrectly, that would burn out your entire controls system.

Tell me if you want coaching on doing that yourself, or if you want to call in an HVAC repair outfit to do it for you. We can go from there.