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Triple-O Heating, Cooling, Electrical & Plumbing Blog

Why Is My Heat Pump Stuck in Cooling Mode?

As the weather cools down, homeowners who use heat pumps for year-round comfort will get to enjoy the best benefit of these systems: it only takes a simple adjustment to the thermostat and suddenly the heat pump goes from delivering cooled air to delivering warm air.

Or least, it should. Any heat pump can suffer from a malfunction—such as staying stuck in cooling mode or simply pushing out room temperature air. If you’re currently having this problem, you’ll want to know why and what to do about it.

Heat pump maintenance reminder

Before we go further and look at why a heat pump might only push out cool air, we need to mention the importance of fall maintenance. Any heat pump requires twice-annual maintenance: first in spring to prep the system for summer weather, then in fall to schedule it for winter.

Having maintenance on your heat pump before you have to switch it to heating mode is the best way to avoid problems such as this. So if you need to schedule heat pump repair in Rochester, NY with our team, make sure to also schedule maintenance.

The broken reversing valve

The most common reason for a heat pump to become locked in cooling mode is a broken reversing valve. This valve is the key component that allows a heat pump to function as both a cooling and heating system. What the valve does is reverse the direction of refrigerant flow as the refrigerant exits the compressor. In cooling mode, the hot, high-pressure refrigerant goes to the outdoor coil first. In heating mode, the valve sends the hot refrigerant indoors, where it releases heat.

The reversing valve may become stuck in place, and this will keep the heat pump trapped in one mode no matter what adjustments you make to the thermostat. To solve this problem, you’ll need to call our technicians to either repair the valve or replace it.

Lost thermostat connection

Changing modes in a heat pump starts when the thermostat sends an electrical current to the reversing valve. When the valve is charged, it switches from its default mode (usually cooling) to its other mode. However, the thermostat can lose its electrical connection to the valve and leave it trapped in the default mode. Technicians can easily repair this by fixing the thermostat’s connections.

Miscalibrated thermostat

The reversing valve may be fine and the thermostat’s connection to it in good shape—but the thermostat isn’t fine. A thermostat can misread temperatures in a house so that it senses the house is warmer than it actually is. In this case, the thermostat won’t change into heating mode because it won’t register that the house needs heat in the first place. Although you can get around this by pushing the thermostat up even higher, we don’t recommend this. A faulty thermostat will create many problems and lead to energy waste, so you’ll either need it repaired or replaced.

Triple-O Heating, Cooling, Electrical & Plumbing Is Your One-stop Shop for HVAC, Plumbing and Electrical. Call us for all your heat pump needs.

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