Matt, what is the role of a reversing valve in a heat pump, and how can you diagnose a malfunctioning valve?

In this edition of “HVAC Skill Builder,” Matt discusses diagnosing a malfunctioning valve and the role of a reversing valve in a heat pump.

Matt, what is the role of a reversing valve in a heat pump and how can you diagnose a malfunctioning valve? The role of a reversing valve in a heat pump mainly serves as adjusting or rerouting the flow of refrigerant depending on whether the system is calling for heating or cooling. Now if you suspect a reversing valve is bad there’s a few things you can do. Number one is you can take off the low voltage wire at the unit and see if the valve will disengage or reengage. Another thing is to make sure the valve is getting the proper voltage going to it from the defrost control board or other mechanism for powering up that valve or you can also use magnets and put them on the outside of the reversing valve so as the valve engages or disengages you can see the magnets move back and forth and diagnose if the valve is actually stuck. Now typically a valve will fail one or two ways either electrically or mechanically so that’s a little bit of advice on how to be able to diagnose that reversing valve depending on the situation that you’re facing.