Q1
How to solve the fault of the cold dryer?
1.Understand clearly the information of the machine nameplate and the model of refrigerant used. The operating pressure values of different types of refrigerant are inconsistent.
For example: Observe the position of the refrigerant pressure gauge pointer to determine whether there will be leakage of refrigerant and other problems.
1.R22:When the fan start, the high pressure is 1.7Mpa, the low pressure is 0.4Mpa.
2.R410A:When the fan start, the high pressure is 2.6Mpa, the low pressure is 0.7Mpa.
410 refrigerant low pressure gauge
410 refrigerant high pressure gauge
Q3
First,determine the ambient temperature is normal, start the machine to observe whether the pressure of the pressure gauge is about 0.4MPA within the normal value, and then touch the side and bottom of the compressor to check whether the cooling temperature is normal.
Q4
If the machine has been bright fault and can not reset boot after power,there are three situations that may cause this problem:
1.Phase sequence protection: the reasons for the phase sequence protection alarm are as follows:
①Measure the voltage with a multimeter to check if there is a phase fault
②Interchange any two phases
③Phase sequence electrical fault
2.Thermal overall relay:
①Whether the protection current setting is reasonable.
3.Check the setting values of the high and low pressure protection switches:
①Low pressure value is 0.2 MPA
Light fault diagram of configuration panel
Q5
The reasons for this problem are as follows:
1. The fan rotates frequently or the rotation time is too long, causing the refrigerant temperature to be lower than zero for a long time, resulting in icing and causing the pressure drop.
2. The unstable or small air consumption of the user for a long time also causes slight icing resulting in pressure drop.
Q6
The cold dryer is divided into air-cooled and water-cooled. The common faults are high pressure trip, low pressure trip, high refrigerant pressure, ice blocking, poor refrigeration effect, and large water content in the air.
Air-cooled type:
When the high pressure trip refrigerant pressure is too high, you can check from the following aspects:
1.Whether the ambient temperature is higher than 40℃(normal temperature should be less than 40℃)
2.Whether the inlet temperature is higher than 60℃ (normal temperature should be less than 60℃)
3.Whether the installation distance of the machine is reasonable (too close to the wall will affect heat dissipation)
4.Whether the condenser is cleaned (dirty blocking will affect heat dissipation)
5.The four points mentioned above need to be explained clearly with customers (or users) in a timely manner, so that they can improve the above four points in a timely manner.
6.In the case of the operation of the cold dryer, low pressure and high pressure are high, and the end air has moisture, which is generally caused by the first point to the fourth point.
7.Whether the fan is damaged (not running) or the control situation of fan pressure switch(damaged or disabled)
When the low pressure trip refrigerant pressure is too low, you can check from the following aspects:
1.Whether the refrigeration system has leakage (external leakage or internal leakage), there are three aspects to determine the fault:
①Observe the value of the residual pressure of the pressure gauge (used to determine the size of the leak point)
②Observe whether there are obvious leakage points such as oil stains inside the machine
③ Whether the discharge of refrigerant has turned yellow and black
2.Whether the refrigerant filter is blocked (if between the copper pipes at both ends of the filter have temperature difference, it can determine the refrigerant filter is blocked.)
3.Opening of expansion valve too small or blocked will also cause low pressure trip (opening can not be too small)
The common fault situation of water-cooled type is the high pressure too high cause trip:
1. Whether the water pressure of cooling water is lower than the use range
2. Whether the water discharge is too small and the cooling water temperature is too high (normal water temperature is less than 32℃)
3. Whether the water-cooled radiator has not been cleaned for a long time (if is not cleaned for a long time will affect the heat dissipation)
4. The opening size of the water regulation valve (not too small)
5. Whether the water inlet manual valve is fully opened
Q7
How to confirm the fault of the compressor and the damage determination measurement method and the replacement points?
When it is confirmed that the power supply is activated and the compressor is not started, the compressor resistance value should be measured and it is divided into single phase and three phases:
Single phase:
1. The high temperature of the compressor in the shutdown state will also trigger overheating protection and cause fault to start.
2. Use a multimeter to check whether the capacitance capacity of the compressor meets the standard. The micronormal number of the rated capacitor is not less than 5%, indicating that the capacitance is normal.
3.Check whether the single-phase compressor is good or bad, use a multimeter to switch to the resistance level and measure the sum of SC+RC=SR on the coils of the compressor. If the following conditions are met, the compressor coils are good.If the resistance value deviates too much or no resistance value, the compressor has a problem.
4. At the same time, use a multimeter to measure whether the compressor terminals are connected to the ground to determine whether the compressor coils are short circuit.
Three phase:
1.Check whether the three-phase compressor is good or bad. Use a multimeter toswitch to the resistance level to measure the compressor coil UV=UW=VU. If the three-phase resistance value is the same and the error is less than 2%, the compressor is good.
2.The high temperature of the compressor in the shutdown state will also trigger overheating protection and cause fault to start.
3.At the same time, use a multimeter to measure whether the compressor terminals are connected to the ground to determine whether the compressor coils are short circuit.
Compressor replacement points:
1. When you need replaced the compressor, discharged the refrigerant pressure of refrigeration system , it is necessary to pay attention to whether the refrigerant will be black, yellow or have other odors during the discharge to determine whether the compressor is burned out due to internal leakage in the evaporator and the cleanliness of the system, as well as the time required to discharge the pressure.
2. After removing the compressor, pour a small amount of oil from the compressor to confirm the level of oil pollution.
3. After removing the refrigerant filter, check whether the inside of the inlet of the refrigerant filter is too dirty or polluted, and purge the radiator to ensure that there is no pollution inside, and then install the refrigerant filter and the compressor for welding connection.
4. After welding connection , press the cooling system and check the welding port to ensure no leakage.
5. After the test pressure is discharged to zero again, the refrigeration system can be vacuumed before the refrigeration system is filled with refrigerant and the machine can be adjusted.
Q8
Evaporator leakage determination method:
1.When the machine is not cooled during operation, but the refrigerant pressure gauge is visually measured in the normal range, you can try to touch the compressor refrigerant low pressure pipe to check whether it will cool. If it is not cooled, check whether there is any oil trace found at the welding port on the inside of the machine. If there is no oil trace phenomenon, it is preliminary determined whether there is the possibility of internal leakage in the evaporator.
2.When trying to discharge the refrigerant pressure of the refrigeration system, it is also necessary to pay attention to whether the refrigerant will bring water and turn black, yellow or have other odors to check whether the evaporator leakage and the cleanliness of the system, as well as the time required to discharge the pressure.
3.When discharge the pressure of the refrigeration system, the refrigerant pressure gauge can not return to zero for a long time. It can be determined that the evaporator is leaking.
Evaporator replacement operation points:
1.When it is necessary to replace the evaporator, it is proved that the refrigeration system and the air system have interacted and the refrigerant is combined with the air to pollute the refrigeration system, and the evaporator can not be replaced directly alone to solve the problem of internal leakage in the evaporator.
2.If only the evaporator is replaced, the replacement parts will be blocked or directly damaged again because the refrigeration system was contaminated before, such as refrigerant filter, compressor and other parts.
3.After the evaporator is replaced, electric welding is carried out first. After the welding pressure test has no leakage, all the pipelines involved in the refrigeration system must be blown out of the water and pollutant residues in the system, and the parts can be installed for welding after thorough cleaning (If the system is seriously polluted, all parts must be replaced.)
4.After welding, press the cooling system and check the welding port to ensure that there is no leakage.
5. After the test pressure is discharged to zero again, the refrigeration system can be vacuumed before the refrigeration system is filled with refrigerant and the machine can be adjusted.