• Heat for a few minutes, then cool air comes on


    When I turn my roof unit on, everything is set on heat. The unit will heat for about 10 minutes, then cool air starts to come out. I also have a small amount of air coming out of some vents in the three bedrooms and the kitchen. I turn the thermostat to 90 degrees and it heats for about two minutes. Then cool air comes out again. I had a tech come see if the unit was working before all of this. He said the unit was in working condition. Can you help me please? I'm a poor man with a problem.

    Tito, aj, AZ

     When your heat cycles on and then cool air starts to blow, a number of issues can be at the root of this problem. In this case, there may be a problem with a safety switch called a high limit. The high limit is designed to shut the unit off once it gets close to an unsafe temperature. The switch could be faulty, which could make the problem very hard to diagnose since there are many electrical components that will work intermittently. The high limit is considered the number one safety switch on a heater. Possibly there could be issues with your thermostat as well. I would suggest having a professional HVAC contractor, like the ARS/Rescue Rooter location in Tucson, AZ at (888) 762-7752, to inspect the unit due to the safety issues involved.