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What should I do when the chiller encounters a high voltage fault?

Mar. 13, 2019

The compressor discharge pressure reflects the condensing pressure, the normal value should be 1.4~1. 6MPa, and the protection value is set to 2.0MPa. If the long-term pressure is too high, it will lead to excessive operating current of the compressor, easy to burn the motor, and easily cause damage to the valve port of the compressor exhaust port. So what are the reasons for the high temperature failure of the chiller? Let's take a look at the coldest bacteria!


First, the cooling water temperature is high, and the condensation effect is poor.

The rated working condition of the cooling water required by the chiller is 30~35°C, the water temperature is high, and the heat dissipation is bad, which will inevitably lead to high condensing pressure. This phenomenon often occurs in the high temperature season. The cause of high water temperature may be: cooling tower failure, such as the fan is not open or even reversed, the water distributor does not turn, the cooling water temperature is high, and it rises rapidly; the outside air temperature is high, the water path is short, and the water volume can be recycled. Less, in this case, the temperature of the cooling water is generally maintained at a high level, and it can be solved by increasing the storage tank.


Second, the cooling water flow is insufficient, and the rated water flow rate is not reached.

The main performance is that the pressure difference between the unit inlet and outlet water becomes smaller (compared with the pressure difference at the beginning of the system operation), and the temperature difference becomes larger. The reason for the lack of water flow is that the system is short of water or air. The solution is to install an exhaust valve at the high point of the pipeline to exhaust; the pipeline filter is clogged or used too fine, and the water permeability is limited. The appropriate filter should be used. Clean the filter regularly; the pump is small and not compatible with the system.


Third, the condenser is fouled or blocked

The condensed water is generally tap water. It is easy to scale when it is above 30 °C. Because the cooling tower is open, it is directly exposed to the air. The dust foreign matter can easily enter the cooling water system, causing the condenser to be blocked and the heat exchange area is small. It is inefficient and affects water flow. The performance is that the pressure difference between the inlet and outlet water of the unit is large, and the temperature difference between the upper and lower sides of the condenser is high. The copper tube of the condenser is hot. The unit should be backwashed regularly and chemically cleaned as necessary.


Fourth, the refrigerant is filled too much

This situation generally occurs after maintenance, which is characterized by high suction and discharge pressure, equilibrium pressure, and high operating current of the compressor. It should be deflated according to the suction and exhaust pressure and the equilibrium pressure and the operating current under rated conditions until normal.


Fives, The refrigerant is mixed with non-condensable gas such as air and nitrogen.

This situation usually occurs after repair and the vacuum is not complete. Can only be drained, re-vacuum, refill the refrigerant.


Six, False positives caused by electrical faults

Due to the moisture, poor contact or damage of the high voltage protection relay, the unit electronic board is damp or damaged, and the communication failure causes a false alarm. This kind of false fault, often the HP fault indicator on the electronic board is not bright or slightly bright, the high voltage protection relay manual reset is invalid, the computer displays “HP RESET”, or it disappears automatically, the compressor running current is normal, the suction and exhaust pressure is also normal.

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