What’s Up With the Heat Pump? Prevent Icing

Many homeowners install an air-source heat pump to heat their homes over the winter, as well as for summer cooling. Since heat pumps extract heat from the outside air for heating, cold weather may cause ice to form on the pump’s outside condensing unit. A small amount of ice is normal, and the heat pump is equipped to deal with it. However, if your outside unit is entirely encased in ice, you have a problem.

Why a Heat Pump Ices Up

A heat pump absorbs heat from the air that runs over the coil in the outside condenser/compressor, using refrigerant that flows through the coils. Changes in pressure, temperature and phases allow the refrigerant to transfer the heat into your home.

Preventing Ice From Forming on Your Heat Pump

When you take heat from already cold air, the process may form ice on the outside coil. If ice or something else is covering the coils, they can’t absorb heat as well and the efficiency of your pump will go down. In order to avoid this situation, your heat pump has a defrost cycle. When the temperature drops and icing occurs, the defrost cycle is automatically activated and run for a sufficient amount of time to melt any frost. The cycle works by essentially running your pump in reverse, which converts the heat pump to its cooling cycle, transferring heated refrigerant outside to melt the frost.

During the defrost cycle, the heat pump’s backup electric heating coil will kick into action to provide heat inside. If you are having significant icing issues with your heat pump despite the defrost cycle, consult with an HVAC professional to see what might be causing the problem. It could be a variety of issues, including a faulty reversing valve.

Sobieski Services can help you with any of your home heating and cooling needs. Our goal is to help educate our customers in Delaware, Pennsylvania, Maryland and New Jersey about energy and home comfort issues (specific to HVAC & plumbing systems).

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