Heat pumps are becoming more and more popular in many parts of the U.S. and for good reason. They’re an incredibly efficient heating option, providing just as much heat as a combustion system while avoiding some of the drawbacks. Like all heating systems, though, heat pumps can develop some unique repair needs over time. One of the most prominent of these is the broken reversing valve. Let’s examine what the reversing valve is, and why repairing it is of such a high priority.
What is the Reversing Valve?
As you probably know, heat pumps are capable of both heating and cooling functions. This is accomplished by reversing the flow of refrigerant between the interior and exterior units. In most forced air systems, the refrigerant flows only in one direction. One unit is the evaporator, while the other is the compressor. In a heat pump, the two units switch these functions depending on the mode selected. The reversing valve is what makes this possible.
The reversing valve is a four-way junction between the intake, exhaust, compressor, and evaporator lines. A slide in the valve determines the direction the refrigerant flows. This slide is attached to a solenoid, an electromagnetic coil, which pulls the slide to one side or the other.
What Causes the Reversing Valve to Break
There are usually only two possibilities when a reversing valve stops working. The first possibility is that the slide in the valve is stuck. This prevents it from directing the refrigerant properly, leaving the heat pump stuck in heating or cooling mode. The other possibility is that the solenoid is broken and/or has lost its magnetic charge. If this is the case, the solenoid will be unable to pull the slide back and forth through the valve. The effect is the same, regardless: the heat pump becomes stuck. If you turn on your heating system and it only blows cold air, the reversing valve might be the reason.