Water pump troubleshooting series

The service life of the water pump is inseparable from regular inspection. The inspection process is mainly to judge the condition of the water pump through the external operation performance of the water pump, so as to find the abnormality of the water pump. Most abnormalities are not irreversible damage to the water pump. If the fault can be diagnosed and maintained at the first time, the water pump can return to normal operation.

There are five main manifestations of abnormal water pump:

Abnormal noise
Abnormal vibration
Abnormal performance
Abnormal temperature rise
Other exceptions

Automatic shutdown of water pump (caused by thermal protector)
During the operation of the water pump with single-phase power supply, the phenomenon of automatic shutdown may occur. This automatic shutdown is not the shutdown operation given by the controller according to the system characteristics, but the shutdown in the form of power failure. This may be the overheating protection of the stator coil triggered by the excessive temperature rise of the motor, resulting in the disconnection of thermal protection, coil power failure and water pump shutdown.

With the passage of time, the stator coil will automatically recover after natural cooling. However, if the cause of overheating is not investigated, the thermal protection shutdown will be triggered repeatedly. After multiple thermal protection shutdown, the water pump stator will be overheated and burned.
The cause of overheating of the water pump needs to be investigated to check whether the starting winding is overheated due to the stuck rotor, or the operating resistance is too large, the motor is overloaded and the operating winding is overheated.

Automatic shutdown of water pump (caused by water shortage protection with control)
For products controlled by water pump, there is usually protection against water shortage at the inlet of the water pump. When there is water shortage at the inlet and the water flow or pressure rise cannot be detected after a certain period of time, it will be judged as water shortage protection and the water pump will be shut down for protection.

Under this protection, there is usually a corresponding display to inform the customer that the water from the pump is short of water, which is convenient for the user to check the inlet pipeline. Some products have the function of automatic reset after water shortage recovery, and some products need to be reset manually.

Water pump does not start
The non start of the water pump mentioned here is not caused by power supply or mechanical failure, but the water pump with the participation of automatic control. Because the set starting pressure of the water pump is too low and the pressure of the incoming water pipe network is higher than the starting pressure of the water pump, the water pump cannot be started.
In this case, it is necessary to increase the starting pressure of the water pump. When the water pump is stopped and maintained, the system pressure is higher than the stopping pressure. When the user uses water, the water pressure drops to the pipe network pressure. At this time, it is lower than the starting pressure of the water pump, and the water pump can start automatically.
The water pump does not stop
Similar to the problem that the previous water pump does not start, when the maximum pressure of the water pump stack inlet pipe network still fails to reach the set shutdown pressure with the participation of automatic control, the water pump will not stop automatically.

At this time, the pump shutdown pressure shall be adjusted downward so that the pump can reach the shutdown pressure and maintain the pressure for shutdown.

Mechanical seal drip
Mechanical seal leakage is usually the initial manifestation of mechanical seal failure. It is due to the foreign matter entering the friction surface of the dynamic and static rings of the mechanical seal, which makes the dynamic and static rings unable to be closed effectively and a small amount of leakage occurs.

At this time, the mechanical seal shall be cleaned. Regardless, two results may be derived. If the water quality is good, the impurities may be washed away from the friction surface, and the mechanical seal will be repaired automatically. If the water quality is poor, more impurities may enter the sealing surface, resulting in scratch and failure of the sealing surface. In fact, the latter is more likely.