How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask airheatman Your Own Question
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8266
Experience:  Furnace, A/C and heat pump specialist.
Type Your HVAC Question Here...
airheatman is online now
A new question is answered every 9 seconds

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: 2 years ago.
Category: HVAC
Expert:  airheatman replied 2 years 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.

Related HVAC Questions