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 I have a Day & Night split unit with the fan coils in the attic and the condenser outside. The unit is about 20 yrs old. When the thermostat is set to heat, the gas turns on, the igniter fires. The heater box heats but the blower fan does not turn on unless the fan is set to "on" on the thermostat. When the fan is set to "auto" the fan will not turn on even after the heater has warmed sufficiently. Is this a simple problem like a limit switch? Or does this sound like something more difficult like the blower control board? I am going to hire a professional, but would really appreciate some guidance so I am not going in without an idea of what it might be.
I appreciate any help you might be able to give me.
Kirk
Answer In a unit of this age, it is most likely a mechanical device that heats up to bring the heat on. It is delayed so the heat exchanger can warm up before bringing on the fan and it is bypassed with the fan in the on position. It is a common part and should be a simple repair. Thanks J
