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airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8039
Experience:  Furnace, A/C and heat pump specialist.
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Having problems with heatpump mod. XPO78COOR4DAA4A ser.NOD9734986

Customer Question

having problems with heatpump mod. XPO78COOR4DAA4A ser.NOD9734986 i reset 24 volt contol voltate and as soon as thermostat calls for cooling transformer trips i traced all wiring and can't find short it seems like it might be the controller board itself thats shorted out but would like to know it there is any way of testing it before replacing it tried to call tech support but get put on hold and never get reply also they don't have a way of leaving call back number
Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.
Hello. My name is ***** ***** I'll do my best to help. Let's get started and see what we can do.About the only way to find the short is to start unplugging components until it no longer trips. I would start with contactors as the coil is pretty common to short on contactors.If we get back to board and with 24v wires coming out disconnected , it still trips, control board is most likely the culprit.

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