• A/C is working, but heat is not


    My programmable thermostat doesn't seem to have power and so the heating is not kicking in. The thermostat itself is fine as I can see it work on the other unit. I checked all the breakers on the panel and they are ok. Would there be any other breakers in the system that would cut off power to the thermostat and/or furnace? The switch in the attic is also ON. It was all working before (AC worked throughout the summer) and the house is only 4 years old. Thanks.

    nasser, bellaire, TX

    From you statement that "the other unit works," my guess is that you're speaking of the A/C unit and the indoor blower. If the blower is working with the call for A/C, then the problem would be associated with the call for heating. Some thermostats have separate circuits for A/C and heating that sometimes require a jumper between two terminals. 

    If this is a new thermostat that was installed during the cooling season this could be the problem.  An easy way to check if this is your problem is to put the thermostat in cool mode, and make sure everything works.  Then set the thermostat to heat, and if there is no power — that would be the indication. 

    Now, if the thermostat is the original one from the builder, then there could be an electrical problem with the thermostat and/or in the furnace itself.  It seems that you have already properly checked the areas that you should before calling for service, but if this is the problem, you should call a qualified technician to check everything out.