How to Maintenance when dehumidifier is fault

2021-09-16

How to Maintain when dehumidifier is faultPls follow up our steps.

 

1. The dehumidifier shuts down after it is turned on, and it can only be restarted after a long time, and the dehumidification effect is very poor.

Check the fault: (1) if the wind speed of the air outlet is lower than the normal value; (2) The resistance value between the lead wires of the fan motor is measured with a multimeter, and it is much lower than the normal value.

Maintenance method: According to the detection situation, it is judged that the motor winding coil is short-circuited, which causes this kind of failure due to the reduction of the fan speed and air volume. Replaced with a new fan motor, troubleshooting.

Analysis: The fan motor speed decreases, and the air volume decreases, that is, the air volume flowing through the condenser decreases, which causes the compressor discharge pressure to rise, resulting in compressor overheating protection ( Shutdown), the compressor overheating will take a long time to cool down before the temperature drops to normal, so the compressor can only be restarted after a long time of cooling.

 

2. Using the dehumidifier in the next year, and it was repaired once. At that time, the test machine was normal, and it was used after a period of inactivity. It was found that the compressor and fan were normal, but the dehumidification effect was very poor. The relative humidity was 83% and the ambient temperature At 12°C, very little water condenses.

Check the fault:

(1) The air filter and the surface of the evaporator condenser are clean;

(2) There is no leaking oil on the surface of the pipeline;

(3) Frost appears on the capillary near the evaporator, and the machine stops shortly. After a period of time, the frost disappears and the compressor can be operated again.

(4) Wrap the interface between the capillary tube and the evaporator with a hot towel, and the dehumidification is normal. It is judged that the refrigeration system is blocked by ice.

Repair method: It is an ice block fault. Clean all the refrigerants with high water content in the system, and pour nitrogen with a pressure of 0.3 MPa to blow the system clean, then use a vacuum pump to vacuum for about 20 minutes, then add the required amount of refrigerant to the original machine, and run for 30 minutes. Stop vacuuming for 30 minutes or more, check that the vacuum degree is confirmed to meet the requirements, fill in the exact amount of refrigerant, start operation, and troubleshoot.

Analysis: When the machine is repaired, water may enter the system or be filled with a refrigerant with a large water content. The elemental water is at the interface between the capillary tube and the evaporator, and the temperature is lower than 0 ℃. Needle-shaped ice crystals are formed here, the ice crystals accumulate, and slowly block the capillary tubes, the refrigerant cannot flow, and the (refrigeration) cannot be dehumidified, and the compressor shuts down due to protection. The air heats the capillary tube to melt the ice crystals and the compressor can resume operation. Repeatedly, the dehumidification effect becomes very poor.

 

3. After the dehumidifier is repaired, it is found that the noise has increased and the dehumidification effect is very poor

Check the fault:

(1) Check that there is no abnormality in the structure of the dehumidifier, and the placement is stable;

(2) Check that the noise mainly comes from the compressor;

(3) The evaporator has no abnormal shape and no frosting phenomenon;

(4) There is more frost in the air return pipe, and it is judged that the refrigerant charge is too much.

Maintenance: properly drain some refrigerant and then turn it on, the dehumidifier will return to normal;

Analysis: When the dehumidifier was repaired, the refrigerant was not charged according to the standard requirements, and the charging amount was too much, which caused the liquid hammer to increase the noise of the compressor, and the liquid droplets in the return air continued to evaporate in the return air pipe to make the return air pipe The surface is frosted.

 

4. The surface of the low-pressure pipe of the dehumidifier is frosted, and the dehumidification effect becomes poor

Check the fault:

(1) The back section of the capillary tube is frosted, and oil stains are found at the interface with the low pressure pipe, and the fault is judged to be a leak

(2) Frost began to form in the front section of the capillary, and no oil stains were found in the pipeline, it is judged that the filter is blocked;

Maintenance methods: (1) Check for leaks, pressurize for leak detection after welding and repair, and fill with refrigerant; (2) Replace the filter.

 

5. After using the household dehumidifier for two years, it was repaired because it was dirty and could not dehumidify, and then used again, the compressor and fan were also operating normally, but did not dehumidify.

Check the fault:

(1) The surface of the air filter and the evaporator are clean;

(2) The working current of the compressor is different from that of the previous failure. The working current of the last failure was very large, but this time the working current was very small. It is judged that the refrigerant is seriously leaking.

Repair method: find out the leak, repair it, and eliminate the fault.

Cause analysis: a large amount of refrigerant leaks. The displacement of the compressor is reduced, the load is small, and the working current is changed.

 

6. The effect of the dehumidifier is not obvious, and the compressor will automatically stop after working for a period of time

Check the fault:

(1) Check the evaporator, the condensed water on the surface is uniform, and it is proved that there is no blockage;

(2) Inspecting the condenser, there is no large temperature difference between the tubes, which proves that the condenser is not clogged;

(3) The compressor will automatically stop after working for a period of time, while the fan operation and control system are normal;

(4) Check the overheating protection of the compressor, it has not acted;

(5) It is estimated that the compressor is faulty, and the protector in the compressor has acted, causing the compressor to stop automatically. The inspection found that the winding resistance when the compressor was just stopped was different from the resistance value when the compressor was cold.

Maintenance: Replaced with a new compressor, the dehumidification function returned to normal. Because of the unstable winding resistance of the original compressor, the temperature of the winding rises quickly when the power is turned on, which causes the protector in the compressor to operate, causing the compressor to stop automatically and cannot perform normal dehumidification. As the internal resistance increases, the power consumption also increases.

 

7. When the dehumidifier is working, it is found that the vibration is very large when it is running, and the dehumidification effect becomes poor, and even it can not dehumidify.

Check the fault: (1) Check the evaporator and find that there is no condensed water on the surface of the evaporator;

(2) Touch the high-pressure pipe by hand, and only warm (normally should feel hot) can be judged as refrigerant leakage;

(3) Check the refrigeration pipe system and find that there are oil traces (leak points) at the interface between the high-pressure pipe and the condenser, which is caused by strong vibration.

Repair method:

(1) Use the oil trace method (or soap foaming method) to find the cracks, and repair the leaks;

(2) Suppress leak detection, vacuum, and refill refrigerant;

(3) Turn on the power to find the cause of the severe mechanical vibration, and it is found that the unloading device cannot operate, which is caused by the malfunction of the electromagnetic reversing valve.

(4) After replacing the solenoid directional valve of the same model, check the leak again, vacuumize, fill the specified amount of refrigerant, restart, and troubleshoot

 


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