As you probably already know, part of what makes heat pumps such great choices for home heating is that they can fulfill both heating and cooling roles. This saves you money and space by removing the need to install an air conditioner in your home. However, being able to provide both of these functions also makes the heat pump a more complicated system. The more complicated a system is, the more ways it is possible for the system to break. If your heat pump won’t switch from cooling to heating, or vice versa, read on to find out why.
How a Heat Pump Works
Heat pumps are not combustion based systems. They don’t burn any kind of fuel to create heat. Instead, they siphon heat from the surrounding air and move it from one place to another. This is done through the use of the two primary parts of a heat pump, the inside unit and the outside unit. These two units are connected to each other by a conduit that both provides power and refrigerant. When the heat is turned on, the outside unit evaporates refrigerant inside a coil to draw thermal energy out of the air. The refrigerant gas, now carrying all of that thermal energy, flows inside to the inside unit. The inside unit then condenses the refrigerant back into a liquid, releasing the thermal energy so that it can heat the home.
The Reversing Valve
The direction the refrigerant flows through the system is what determines whether the heat pump is in heating or cooling mode. If the refrigerant is flowing one way, the outside unit captures heat to send it inside. If the refrigerant flows the other way, the inside unit captures heat and sends it outside. The part that determines the direction of refrigerant is called the reversing valve.
The reversing valve is a 4-way junction in the heat pump’s refrigerant line, which determines the direction that refrigerant flows through the system. In heating mode, a slide in the valve forces the refrigerant to flow in one direction. In cooling mode, the slide moves to force refrigerant to flow in the opposite direction. If a heat pump won’t switch modes, it’s a sign that the reversing valve is stuck in one position. If the valve can’t move, the refrigerant flow can’t be reversed and the heat pump becomes stuck in one mode.