Knowing Your Home’s Heat Pump Defrost Cycle
In basic terms, your home’s heat pump pulls heat from the environment and moves it into your home. The heat pump is used not only to heat your home, but can also be used to cool it.
What Is the Heat Pump Defrost Cycle?During the winter months, depending on temperature and humidity factors, frost may form on the outer coil of the heat pump. When this happens, the pump must work harder, and starts working less efficiently. In order to resolve this, the heat pump has a defrost cycle. When the heat pump defrost cycle is triggered, the heat pump switches over to the cooling cycle temporarily. This causes the outside coil to warm up. The outdoor fan is stopped to prevent it from cooling the outside coil. The defrost will continue until the temperature of the outside coil reaches about 57 degrees.
How Does This Affect My Heat?During the heat pump defrost cycle, the indoor fan will continue to run, and your system will be in cooling mode. In order to avoid cold air from circulating throughout the house, a heating element can be installed that triggers when the pump goes into defrost mode. A well-running heat pump should run in defrost mode at timed intervals, and can run from 30 seconds to a few minutes.
Why Isn’t My Heat Pump Defrost Cycle Working?There are several reasons why your heat pump defrost cycle isn’t working properly. An older system may begin running the cycle when it isn’t necessary. In other cases, the defrost cycle may not come on when it needs to, which can damage the heat pump. There are a few reasons this may happen:
- Wiring problems
- Thermostat malfunction
- The outdoor coil is dirty or covered with debris