One of the topics I enjoy writing about the most is heat pumps. This is because heat pumps can pull a nifty trick: provide both heating and cooling to a home. And, like the best magic tricks (such as pulling a poodle out of a hat), once you know the secret behind it, it feels both obvious and sorta genius that you have to admire the folks who came up with it. I’d love to take credit, but that would be dishonest and even counting in dog years I can’t stretch my lifetime back that far to the late 1940s. (The actual inventor was Robert C. Webber. Yep, I know that much about HVAC.)
I could go on for a long time about the workings of heat pumps, but I want to look at one special part that makes all the difference—the part that is essential in allowing a heat pump to work as an air conditioner and a forced-air heater. It’s called the reversing valve.
The Reversing Valve Basics
A reversing valve is a metal component that looks like a copper bar with multiple copper tubes intersecting it. In technical terms, this device is an electro-magnetic four-way valve that guides the direction of the refrigerant that comes out of the compressor in the outdoor cabinet of the heat pump.
Inside the valve is a slider; when it shifts position, it changes the direction of the incoming refrigerant to either move it first toward the indoor coil (which would put it in heating mode) or first to the outdoor coil (which would put it in cooling mode). The slider is moved by connecting electricity to the valve, energizing it. When the valve is de-energized, the slider returns to its first position. In most heat pumps, energized is cooling mode and de-energized is heating mode.
When you manipulate the thermostat to adjust the heat pump, the thermostat will either send an electrical signal to the reversing valve or de-energize it, which determines which mode it will be in.
Reversing Valve Troubles
There are plenty more details about the operation of the reversing valve, but I’m not going to go full “Electro-Engineer Olive” on you. What’s important for you to know is what can go wrong with the reversing valve that can lead to heat pump trouble.
For one, the slider can become stuck, which is what you might expect from any mechanical device with enough wear. It can get stuck either in heating mode or cooling mode.
The other common trouble is when the thermostat loses its connection to the reversing valve. If the thermostat cannot energize the reversing valve, the heat pump will remain in its default de-energeized mode, which in most cases means a heat pump that’s stuck in cooling mode.
Fixing problems with a reversing valve is a standard repair for our great team. Sometimes we can repair the thermostat connection, and other times we’ll need to remove the reversing valve and replace it. No matter what type of heat pump repair in Maryville, TN you need to stay warm/stay cool, you can trust us to do the job.