- Be certain that the thermostat is set higher than the actual room temperature and the selector switch to heat if in heating mode, or that the thermostat is set lower than room temperature and the selector switch is on cool if air conditioning is desired. If the thermostat is programmable, make sure it has fresh batteries.
- An easy test for power is to move the fan switch from "auto" to "on". If the blower runs there is power to the unit. If you are familiar with the fuse panel or circuit breaker panel, check for blown fuses or tripped breakers. Correct the problem once. If it repeats, call for service.
- Check the water supply if fed from a well. A clogged filter or strainer may trip safety switches that will not allow the unit to run without water.
- Because the controls are mounted internally and high voltage connections are exposed if the cabinet is opened, only a qualified technician should access them.