Heat Pump Blowing Cold Air in Heat Mode (Trane & American Standard)
If your Trane or American Standard heat pump is blowing cold air while set to heat, it usually means the system is not switching modes correctly or is stuck in a normal operating condition that feels wrong to homeowners.
What should normally happen
In heating mode, a heat pump will often blow air that feels cooler than a gas furnace. It should still raise the room temperature steadily.
Common causes (most likely first)
- System is in defrost mode
- Thermostat configuration issue
- Reversing valve not shifting
- Heat pump locked out (Not actually running)
Safe homeowner checks
- Verify thermostat is set to HEAT, not EM HEAT
- Check air filter, replace or remove if clogged
- Make sure outdoor unit is not completely iced over and actually running. Frost is okay, ice is not. If outdoor unit is not running, and thermostat says it should be, a reset may be required.
- Check breakers for indoor and outdoor units, verify “on” status. If all this checks, reset both breakers by turning both (indoor and outdoor units) off, waiting 2-5 minutes, and then turning back on.
When this becomes a technician issue
If the unit continues blowing cold air and the home temperature drops, even after resetting breakers. Electrical testing of the reversing valve circuit or control board is required. Or, more commonly, a possible refrigerant issue needs to be diagnosed.
Parts commonly involved
- Refrigerant
- Defrost control board
- Air Filter
- Thermostat