AboutJ Cook Expertise With 25+ years experience, I am familiar with residential, commercial, and industrial HVAC equipment including but not limited to boilers, chillers, reciprocating and screw compressors. I am trained in all manners of control wiring.
Experience I currently have three HVAC licenses and Refrigeration license by the State of North Carolina. I have been in this field for over twenty years. I have been a service technician for a contractor and also worked at a state college in the repair and maintenance of steam lines and equipment. I am currently the Building Maintenance Superintendent for a municipality.
Question My Question is what can check to see why my ac and heater will not turn? The blower will not turn when switch to fan on. I have check the breaker and it is fine. I have check all wiring. I have reset the t-stat and the heater worked for 4 days. So, I replaced the t-stat and the heater worked for 2 days. I have jumped the red and green wire to turn blower on, but it will not kick on. I have jumped the red and yellow and the outside unit will not turn on. This was all done at that t-stat. I had a friend look at it that works on residential unit but is at lost. Any suggestions. Thank you for your time!!!
Answer To have directly jumpered what you did with the thermostat wiring and it did not operate, I suspect the transformer has failed. It will be in the indoor unit. Locate the thermostat strip that will have the same letters as the thermostat. The wire connected to the R terminal will be directly from the transformer. There will be a second wire to the common terminal on this strip from the transformer also. See between the two wire a voltmeter if you have 24 volts. If not, make sure the transformer is getting 240 incoming volts. If you have 240 in and do not have 24 out, the transformer is bad. Thanks J
