What causes air source heat pumps to freeze and crack?

Insulation and antifreeze measures for air source heat pump units in winter are very important. Any carelessness will cause direct economic losses to users, or even more serious consequences. Chuangyu Refrigeration summarizes the following reasons with you based on actual situations during the maintenance process:

The unit is powered off for a long time:
When the temperature is below -5℃, if the power outage time exceeds 4 hours, it is likely to cause the heat exchanger to freeze and crack. In particular, when the fluorine system and the water system are frozen at the same time, when the compressor restarts after the power is on, the compressor will directly absorb the water in the outside water system into the fluorine system, causing the entire unit to be scrapped. Therefore, when it is judged that the power may be off for a long time, the water in the unit, water pump, and outdoor pipeline should be completely drained to prevent the unit from freezing.

The unit motherboard design does not have an antifreeze protection function:
When the temperature is below zero ℃, as long as the unit is powered on, regardless of whether the unit is in working condition or reporting a fault code, the unit will automatically power the circulation pump for 10 to 15 seconds every 30 minutes, so that the hot water in the water tank circulates between the water tank and the main unit, and uses the hot water in the water tank to heat the valves, pipes, water pumps and unit heat exchangers to prevent freezing and cracking. However, the machine design of each manufacturer is different. Some machine motherboards do not have an antifreeze protection function. Once a fault occurs, it may cause the heat exchange sleeve to freeze and crack.

The water flow switch or the water flow switch is short-circuited, and the temperature probe is inaccurate:
When the air source heat pump is cooling in summer, the unit stops working when the water temperature is from ℃ to 10℃, and starts working when it is higher than 15℃. If the water temperature probe measures the water temperature inaccurately, for example, the water temperature has reached 0℃, and the probe shows that the temperature is still 25℃ (more than 15℃), then the machine determines that the water temperature has not reached the temperature that needs to be stopped, and will continue to cool. At this time, if the water flow switch is not installed or the water flow switch is short-circuited, it is likely to cause the unit to freeze and crack.