8 major faults and elimination methods for frosting of ultra-low temperature air source heat pump evaporator
Column:Industry News Time:2018-11-19
8 major faults and elimination methods for frosting of ultra-low temperature air source heat pump evaporator

In the winter, the frosting of the ultra-low temperature air source heat pump water heater evaporator is a normal phenomenon, but if the frost cannot be normalized after frosting, or even icing, it
will seriously affect the heating effect. The judgment steps and troubleshooting methods are as follows:

First check if the settings are correct, and whether the settings such as defrosting start time, starting temperature, defrosting time, and defrosting end temperature are reasonable. Under normal
circumstances, the defrosting factory setting start temperature is 2 ~ 4 ° C, the defrosting time is 30 ~ 45 minutes, the defrosting end temperature is generally about 10 ° C. Check if these settings
are reasonable before proceeding to the next step.


Stellar air source heat pump

The evaporator frosting is divided into the following 8 cases:

Frost on the bottom of the evaporator

Most of them are caused by poor drainage of the water tray. After artificially defrosting with hot water, clean up the dirt and keep the drain water drained.

It should be noted that if the evaporator is found to be frosted, do not use hard things to remove it. It is easy to cause damage to the copper tube or even leakage of the refrigerant. The best method
is to use hot water to rinse.

Evenly frosted on both sides of the evaporator, and has not been frosted

Check the defrosting temperature, or place the host defrosting probe in the cream. After 3 minutes, if the defrosting temperature is above 5 °C, it can be judged that the defrosting probe is faulty,
shower with hot water, after artificial defrosting Replace the defrosting probe.

If the compressor is working properly, reversing the four-way valve or directly energizing the four-way valve. If there is no sound from the four-way valve, and the sound of the refrigerant is not heard,
it is basically determined that the four-way valve is broken. If there is a sound of suction, but there is no sound of refrigerant flow, it is because the four-way valve is stuck and cannot be reversed, which
causes the evaporator to frost. At this time, the four-way valve needs to be replaced.

Defrost is not complete

It can be defrosted after frosting, but the defrosting is not clean, not thorough, or there is frost on one side and no frost on one side. This situation is generally due to:

If the defrosting end temperature setting is too low or the defrosting time is set too short, the defrosting end temperature and the defrosting time can be appropriately adjusted;

The position of the defrosting probe is unreasonable. At this time, the defrosting probe can be placed in the most severe place of frosting.

Frequent frosting in a short time

First check if the defrosting temperature is normal. If the defrosting temperature is normal, below 0 °C, first check whether the ventilation around the host is good, clean the debris around the main unit
and clean the evaporator, and extend the defrosting time and increase the defrosting temperature. .

The host frequently frosts and the pressure of the pressure gauge is low. First, use hot water to artificially defrosting the frost, and then observe the low pressure gauge during heating. If the pressure is
lower than the normal value (can be compared with similar models), it can be judged that the refrigerant is insufficient. Or refrigerant leaks.

The main fan motor is damaged or the air volume is insufficient, such as blade damage, or the fan motor power is too small.

Partial frosting of the evaporator

Uneven frost or partial frost on one side or both sides of the evaporator. This is because the refrigerant is not evenly distributed. Most of the tubes are not smooth or blocked by ice. The removal
method is to move the defrosting probe to First replace the frost on the copper tube that is not easy to defrosting or replace the capillary tube, re-vacuate and add refrigerant.

High voltage protection during defrosting

This is because the end of the defrosting temperature setting is too high, and the defrosting temperature can be appropriately adjusted. It is generally set to 10 °C.

Low pressure protection during defrosting

This is caused by the blockage or excessive opening of the throttle expansion valve in the reverse direction. At this time, it is necessary to replace the throttle expansion valve or to adjust the opening
degree of the throttle expansion valve. The specific mediation method is generally detailed in the manufacturer's manual. Explain that the parameters of different models are not the same. There is no
way to explain them in a unified way.

No frosting is also defrosting

This is because the startup defrosting temperature setting is too high, or the defrosting probe is broken, causing the machine to malfunction. At this time, you only need to adjust the defrosting start
temperature or replace the defrosting probe.

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