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Proudly Serving Yakima, Ellensburg, Cle Elum, and the Surrounding Areas Since 1998

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Proudly Serving Yakima, Ellensburg, Cle Elum, and the Surrounding Areas Since 1998


ThermAll Heating, Cooling & Electric Blog

How a Heat Pump Can Get Stuck in One Mode


We love heat pumps here in Washington State. They’re an ideal way to provide comfort for a home around the year. During our summers, they have the power of the best air conditioning systems to cool down a house without excessive energy waste. Then, during our winters, heat pumps always have enough thermal energy outdoors to pull into a house to keep it cozy—and with far less electrical power than a furnace uses.

Because heat pumps can switch between heating and cooling modes, they can also run into a malfunction where they get stuck in one mode or another. You may run into trouble during the winter and discover your heat pump will only work in cooling mode when you turn it on. Not a good situation in cold weather! We’ll take a look at why a heat pump might have this problem and when you’ll need to call us for heat pump repair in Ellensburg, WA.

Broken Reversing Valve

This is a malfunction that sometimes occurs in heat pumps and which requires professional repairs to correct. The reversing valve is a key component of a heat pump that separates it from a standard air conditioner. The valve controls which direction refrigerant rotates through the system: as hot refrigerant exits the compressor, the valve either sends it one direction or another, and the direction it moves determines if it’s in heating or cooling mode.

The valve can become stuck in place or fail to energize when it receives a signal from the control board. This will make it impossible for the heat pump to switch modes. To fix this, professionals will usually need to replace the reversing valve.

Faulty Thermostat

Thermostat issues account for several types of HVAC problems, and it’s always worthwhile to investigate the thermostat(s) in your house when your heat pump isn’t working the way it should. The thermostat is responsible for signaling to the heat pump to switch modes, and it can lose this connection while still being able to control the fan or other parts of the HVAC system. The thermostat may also have a miscalibration so it’s not reading the temperatures accurately in your home. This may cause it to not switch the heat pump over to heating mode when necessary. HVAC technicians can diagnose the thermostat problem and find the repair, recalibration, or replacement to solve it.

Electrical Issues

Trouble with electrical components is a leading cause of problems in heat pumps and air conditioners. A faulty control board or faults with relays can lead to a heat pump not following any of the instructions the thermostat sends to it. 

Activated Safety Mechanism

Some heat pumps have special safety devices that will lock the heat pump’s operation into a single mode when it detects an error. This is designed to prevent damage to the unit, so you’ll need HVAC professionals to find the original problem and fix it so the heat pump will operate without damaging itself.

Call ThermAll Heating & Cooling, Inc for your heat pump needs: We are “Your Home Comfort Hero!” 

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