Cause analysis of deep well pump failure:
Although deep-well pumps are vertical long-shaft multi-stage centrifugal pumps (or mixed flow pumps), the reasons for their failures are quite different from those of ordinary horizontal pumps. Troubleshooting should be based on the principle of “easy first, then difficult, first uphole and then downhole” to find out the main cause of the failure and eliminate the symptoms.

1 Although the deep well pump produces water, its output is very small:
In this case, the water level of the well should be measured first. If the water level of the well drops too much, it means that the water inflow of the well is less than the designed water output of the pump. As a temporary measure, the outlet of the small pump can be shut down, and for long-term measures, a pump with a smaller flow rate should be replaced.
If the well water level does not drop significantly, it may be that the overflow part is blocked by sand, debris, etc., or the impeller and the deflector shell have been worn out in direct contact. At this time, the pump should be lifted to clean up the dirt, or the impeller should be replaced .

2 It is difficult or impossible to start the deep well pump:
This kind of failure often occurs when a new pump is commissioned or is disabled for a long time for the first time. If the switch is turned on, the fuse is blown immediately, or the motor does not rotate but only buzzes, or the number of rotations is not enough, it is a starting fault. At this time, you should first check whether the motor wiring is proper, and measure the voltage to see whether it is too low. If the wiring is wrong, you should correct the wiring error; if the voltage is low, you must further check whether the power supply voltage is low, or the wire number is small, the transformer capacity is not enough, the transformer is too far away from the unit, etc., check one by one, and take corresponding measures. Measures to be resolved.

3 Although the deep well pump rotates, it does not produce water:
If the well pump is started up to the normal number of revolutions, but there is no water output for 1 or 2 minutes, or the water output is suddenly interrupted during normal operation, stop immediately and check again to avoid dry friction and burn out the rubber bearings and impellers, causing vibration or even shaft broken accidents. 

During the inspection, the water level of the well should be measured first to see if the inlet of the pump is exposed to the water surface or air is sucked in due to the excessive drop of the well water level. At this time, the outlet door of the small water pump should be closed to reduce the water output. If this happens many times or repeatedly, you should change to a pump with a smaller flow rate. Secondly, consider whether the flow part of the pump, such as the filter pipe, impeller, and diversion shell, is blocked by debris; in addition, mechanical failures, such as excessive impeller wear, pump shaft breakage, water delivery pipe breakage, tripping, etc., can all cause wells. The pump does not produce water. At this time, you need to lift the pump out of the well and check one by one.

4 The power unit of the deep well pump is overloaded during the working process: the main reasons are:
① There is friction between the impeller and the deflector shell, so stop the machine and adjust the gap.
②The ball bearing of the motor is damaged. Stop the machine and replace the bearing.
③Due to incomplete well washing, the water pump is blocked by sediment or stuck by debris. At this time, the water pump should be lifted to clean up the sand or debris, and re-wash the well if necessary.