How to maintain air-energy water heaters?

Air-energy water heaters have always occupied a large market in the South. The climate is severely cold in winter, so maintenance of air-energy water heaters must be strengthened. Consumers who purchase air-source water heaters in summer may not pay attention to some maintenance methods of air-source water heaters in winter. However, air-source water heaters malfunction more frequently in winter.

In northern winter, the most common problem for air-source water heaters is frosting on the evaporator, which will reduce its ability to absorb heat in the air, affect the working efficiency of the machine, and even cause the compressor to fail to start.
Based on the major disadvantages of air-based frosting, a lot of research has been done on defrosting technology at home and abroad. There are currently three defrosting methods commonly used in our country, namely reverse cycle defrosting, hot gas bypass defrosting, and energy storage defrosting. 
1. When reverse cycle defrost is used, the four-way reversing valve operates to change the refrigerant flow direction, allowing the unit to convert from a heating state to a cooling state. The high-temperature gas discharged from the compressor is directly passed to the outdoor heat exchanger for defrosting. It can be seen that the defrosting energy of this method comes from the power consumption of the compressor and the heat absorbed from the room. When the defrost is started, the refrigerant exists in the gas-liquid separator in a liquid state. The compressor can only disperse the refrigerant by pulling the suction pressure very low, resulting in a very small refrigerant flow during the defrost stage, which prolongs the defrost period. time. This method is easily affected by ambient temperature and humidity, and the system stability is poor during defrosting.
2. The hot gas bypass defrosting method does not change the flow direction of the refrigerant. The unit maintains the heating working state. The high-temperature gas discharged from the compressor directly bypasses part of the high-temperature gas discharged from the compressor through the bypass pipe to the outdoor heat exchanger for defrosting. The heat source of defrost is the electricity consumed by the compressor and the heat storage of the compressor shell. Compared with the reverse cycle defrosting method, it has less impact on indoor comfort. However, the defrosting time is long, the energy consumption loss required for the defrosting process increases, and the energy-saving effect is not good.
3. Energy storage defrost includes hot water storage and phase change material energy storage. Phase change thermal storage defrost is a new defrost method proposed in recent years. During the defrosting process using the energy storage defrost mode, the energy storage heat exchanger acts as an evaporator to provide heat for defrosting. Studies have shown that energy storage defrost can provide a relatively good defrosting heat source, shorten the defrosting time, have a short recovery time, have good energy-saving effects, and reduce greenhouse gas emissions, which is superior to other methods. The disadvantage is that the initial investment cost is relatively high.

In winter, in addition to timely defrosting, there are some other maintenance tips that I would like to share with you. When the temperature drops in winter, you need to switch the three-way reversing air valve to the outdoors. At the same time, set the machine mode to the standard heating mode and set the hot water temperature to 55°C. This will not only ensure the comfort of the hot water, and can meet the hot water supply needs. When the water consumption at home increases, the target temperature of hot water needs to be set higher, so that the demand for water heaters can be fully met. It is necessary to frequently check whether the water replenishment, water tank safety valve, liquid level controller, and exhaust device of the water system are working properly to prevent air from entering the system and causing a reduction in water circulation, thereby affecting the heating capacity of the unit and the reliability of the unit's operation. This is key to ensuring hot water in winter.