What Heat Pump Repair Involves
Because a heat pump reverses its refrigerant flow to switch between heating and cooling, the reversing valve is one of the most common points of failure and one that a standard air conditioner does not have to worry about. A stuck reversing valve can leave a heat pump blowing cold air when it should be heating, or vice versa, and diagnosing it correctly requires checking valve position along with refrigerant pressures rather than assuming a refrigerant problem.
Outdoor heat pump units also deal with a defrost cycle in winter that a straightforward air conditioner never runs, since the outdoor coil can frost over as it pulls heat from cold outside air. A defrost control board or sensor that fails will either let ice build up until the unit cannot function, or cycle into defrost too often, wasting energy and reducing heating output. We test the defrost board, sensors and reversing valve solenoid as part of any heat pump diagnosis.
Beyond the components unique to heat pumps, the same refrigerant circuit, compressor, capacitor and electrical issues that affect air conditioners apply here as well. We check the full system, not just the parts specific to heat pump operation, since a weak capacitor or failing compressor will affect both heating and cooling modes.