Frost protection is an automatic function that prevents damage to the heat pump in cold weather. Water remaining in the pump's heat exchanger could freeze at sub-zero temperatures. Since ice has a greater volume than water, this process could irreversibly damage or even rupture the sensitive internal components of the device. The function activates as soon as sensors detect a temperature drop to a critical threshold, and initiates water circulation or short-term heating to maintain the temperature inside the pump above freezing point.