Why Your Heat Pump Is Covered In Frost

A heat pump is a great choice for any Raleigh-Durham home, serving double duty as both heating and cooling system for year-round comfort. A heat pump is designed to withstand the outdoor elements, and as outdoor temperatures fluctuate it’s not unusual to see a light buildup of frost—but once this frost turns to ice and you have a frozen heat pump, you need to take action. Read on to learn what can cause your heat pump to freeze up, and what you should do when it does. 

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The Science Behind A Frosty Heat Pump

During heating season, a heat pump draws heat from the outdoor air and transfers it inside. This reverses during cooling season, moving heat outside instead of bring it it in. The pump transfers heat by circulating refrigerant through the evaporator coil where the heat is absorbed, and then through the condenser coil, where it is released. During this process if the temperature variation and humidity levels are favorable then condensation is formed on the evaporator coil. If the coil is too cold the condensation freezes. Heat pumps have an integrated defrost cycle designed to prevent the outside unit from freezing over, but any number of issues can hinder it from doing its job, as you’ll see below.

What Causes A Frozen Heat Pump?

While a few of the following concerns can be easily addressed by the homeowner, others require the services of a qualified professional:

Restricted Airflow

If the flow of air across the coils is hampered by debris (such as leaves, grass or snow), a dirty air filter, blower malfunction, or blocked return vents, ice will begin to form. Ensure the area surrounding the unit is clear, and furniture or draperies are not blocking return vents.

Low Refrigerant

Low refrigerant levels due to an improper charge or leak, causes a drop in system pressure and a significant drop in temperature. Once the evaporator coil gets too cold, condensation rapidly freezes and the unit ices over.

Dirty Evaporator Coil

Dirt or debris can adhere to the coil which is consistently wet due to condensation. This added layer of insulation causes the coil to get too cold, and may freeze over.

Mechanical Issues

Faulty valve operation, malfunctioning defrost thermostat, defrost control, outdoor fan motor, defrost relay, reversing valve solenoid coil, or other mechanical or electronic issues may be the cause and should be inspected and serviced by a professional.

Leaky Gutter/Freezing Rain

External sources of water falling on top of the outdoor unit can quickly turn to ice, blocking airflow and causing ice to form on the rest of the unit.

Heat Pump Repair Services in Raleigh-Durham

The highly trained, experienced professionals at Comfort Services Heating & Cooling will complete your frozen heat pump repair efficiently and effectively, to get your HVAC system up and running as soon as possible. Call 919-646-8019 to schedule service, receive a free estimate, or for 24/7 emergency service, or contact us online and let us know how we can help.

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