Heat Pump Defrost Cycle
Is Your Heat Pump Making Strange Sounds?
If you have been left wondering why your heat pump is making strange noises in the cold weather lately, one possibility is the defrost cycle. When in defrost mode, heat pumps can make a gushing, low humming or whooshing sound & if you are unfamiliar with this noise, it could be a little concerning.
What Is The Defrost Cycle?
The defrost cycle is activated when the temperature of the outdoor coil drops & frost or ice can form reducing the air flow, which can cause loss of efficiency or damage.
In heating mode a heat pump extracts heat from the outside air & transfers it inside to warm your home or commercial space. When the ambient temperature outside gets very cold, the moisture in the air freezes on the outdoor unit's heat exchanger as the fan blows the air across it.
When the heat pump goes into defrost mode, it momentarily reverses operation and goes through the “cooling cycle.” This forces warm air through the outdoor coil, warming it temporarily to remove the frost.
What Happens To The Heat Pump During The Defrost Cycle?
In defrost mode you may notice the indoor unit temporarily stop heating, the indoor fan will stop or slow down depending on the model, you may feel some cold air and there maybe be some visual indication such as blinking lights on the indoor unit. The outdoor unit's fan will stop however the compressor will be running.
The sound your heat pump will make in defrost mode will differ depending on the make and model as well as the pipe length.
A normal cycle may take 10 - 15 minutes.
If your heat pump is frequently going into defrost mode, is defrosting for a prolonged period of time, or has a lack of heat, there may be an issue that requires diagnosis. Call 03 366 1823 to book a diagnosis or maintenance appointment.
