In winter, the frosting of the evaporator of ultra-low temperature air source heat pump water heater is a normal phenomenon, but if the frosting can not be normalized, or even ice, it will seriously affect the heating effect. The judgment steps and exclusion methods are as follows:
First, check whether the settings are correct, and whether the settings of defrosting start time, start temperature, defrosting time and defrosting end temperature are reasonable. Generally, the starting temperature of defrosting is 2 - 4 C, the defrosting time is 30 - 45 minutes, and the end temperature of defrosting is about 10 C. First check whether these settings are reasonable, and then proceed to the next step of judgment.
Evaporator frosting can be divided into the following eight situations:
1. Frosting at the bottom of evaporator
Most of them are caused by the poor drainage of the drainage pan. After artificial defrosting with hot water, the sewage can be cleaned up and the drainage of the drainage pan can be maintained smoothly.
It should be noted that if the evaporator frosts, do not use hard things to clean, easy to cause copper pipe damage or even refrigerant leakage, the best way is to use hot water to rinse.
2.Evaporator frosts evenly on both sides of the evaporator and does not defrost all the time.
(1) Check the defrosting temperature, or place the main defrosting probe in the frost body. After 3 minutes, if the defrosting temperature is above 5 C, it can be basically determined that the defrosting probe is out of order. After defrosting with hot water, the defrosting probe can be replaced by manual defrosting.
(2) If the compressor works normally, the four-way valve is operated by reversing direction, or the four-way valve is electrified directly. If there is no sound of the four-way valve sucking up and no sound of refrigerant flowing, the coil of the four-way valve can basically be judged to be broken; if there is sound of sucking up, but there is no sound of refrigerant flowing, it is because the four-way valve is stuck. Do not open, can not change direction, resulting in frost evaporator, at this time need to replace the four-way valve.