What Does a Defrost Control Board Do?
TechXpert verified by Ken Kontra
Your defrost control board is responsible for defrosting your outdoor heat pump unit. When cold air strikes, ice builds up on your heat pump’s outdoor unit. Your defrost control board is responsible for monitoring the sensors that test your system for ice, and then activating its defrost mode. Defrost mode melts the ice that forms on your heat pump’s outdoor refrigerant coil to restore efficient operation.
As temperatures drop outside, your heat pump starts to get frosty. It's normal to see light ice buildup on your unit in the winter, but if you're noticing heavy frost, this means your system has a bad case of the chills.
Duties of a Defrost Control Board
Your defrost control board is responsible for monitoring the heat pump’s operating conditions that are likely to form ice. When it’s malfunctioning, the heating output of the heat pump will decrease. This means the thermostat won’t be able to maintain the temperature setting and the auxiliary or supplemental heat will automatically operate to keep you comfortable. Though the auxiliary heat keeps you comfortable, you do not want to rely too heavily on it — it is costly to operate over long periods of time.
Heat pumps will defrost to help protect the unit as well as keep your system running efficiently. Defrost mode is activated by sensors that test the run time and operating temperatures of your heat pump: If the sensors indicate your heat pump is cold enough for long enough, your defrost control board signals your unit to go into defrost mode.
Say Goodbye to Winter Worries
If your heat pump caught a cold it just can't shake, there’s likely a problem with your defrost control board. Frost buildup on your system can demand more energy and damage your unit, so it's best to get to the bottom of your problem quickly and say goodbye to those winter worries with a call to your local HVAC contractor.
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