A reversing valve is the four-way valve in a heat pump's outdoor unit that changes the direction of refrigerant flow, switching the system between heating and cooling. A solenoid shifts the valve on a signal from the thermostat or control board. The same valve reverses the system briefly during each defrost cycle in winter.
Why it matters to you
Because a Fraser Valley heat pump switches between heating, cooling and frequent winter defrost cycles, the reversing valve gets regular use. A valve stuck in one position can leave a home blowing cool air on a cold, wet morning.
Practical guidance
If a heat pump blows cool air in heat mode or warm air in cooling mode, first check the thermostat mode and settings, then call for service. Diagnosis needs refrigerant gauges and electrical tests, so it is not a homeowner repair.