Performed preventative maintenance on 3 systems. Had customer show me system locations, filters, and thermostats. Customer changed filters not too long ago, so I left them replacements. Upstairs air handler has a 5 kw heating kit in it. I inspected the blower motor, capacitor, electrical components, evaporator coil and ductwork. Checked thermostat operation, wiring, amps, and temperatures of system. All components are operating properly. I checked the downstairs system next which is a gas furance. Customer had thermostat set to heat, but the AC was running. Customer stated the unit is a heat pump, but I checked the unit over and it is a straight AC. Customer had thermostats installed a while back and was told the unit is a heat pump and the settings on the thermostat have been set to heat pump. This was causing the ac to run for an extended period of time before the gas heat would kick on to get the temperature back up again. Evaporator coil was semi frozen and the txv was caked in ice