In the process of maintenance, the diagnosis of pump failure is a key link, the following common faults and elimination measures. Do a simple analysis here.

1、No liquid supply, insufficient liquid supply or insufficient pressure

　　(1) The pump is not filled with water or is not properly vented.

Solution: Check that the pump casing and inlet lines are all filled with liquid.

　　(2) The pump speed is too low.

Remedy: Check if the motor wiring is correct, the voltage is normal or the turbine pressure of the turbine is normal.

　　(3) The water head of the pump system is too high. Take the safety tips for safety.

 Solution: Check the head of the system (especially the friction loss).

　　(4) The pump suction stroke is too high.

Solution: Check the existing net head (the inlet line is too small or too long will cause a large friction loss).

　　(5) The pump impeller or pipeline is blocked.

Solution: Check for obstacles.

　　(6) The direction of rotation of the pump is incorrect.

Solution: Check the direction of rotation.

　　(7) The pump generates air or the inlet line has a leak.

Solution: Check the inlet line for air pockets and/or air leaks.

　　(8) The packing or seal in the pump packing box is worn out, so that air leaks into the pump casing.

Remedy: Check the packing or seal and replace as needed to check if the lubrication is normal.

　　(9) Insufficient suction head when pumping hot or volatile liquid.

Solution: Increase the suction head and consult the manufacturer.

　　(10) The bottom valve of the pump is too small.

Solution: Install the correct size bottom valve.

　　(11) The bottom of the pump bottom valve or inlet pipe is not deep enough.

Solution: Consult the manufacturer for the correct immersion depth. Use a baffle to eliminate eddy currents

　　(12) The pump impeller clearance is too large.

Solution: Check that the gap is correct.

　　(13) The pump impeller is damaged.

Solution: Check the impeller and replace it as required.

　　(14) The diameter of the pump impeller is too small.

Solution: Consult the manufacturer for the correct impeller diameter.

　　(15) The position of the pump pressure gauge is incorrect.

Solution: Check that the position is correct and check the outlet nozzle or pipe.

2、The motor does not rotate when the micro water pump is started.

　　(1) The power supply is out of phase and the line is open.

Remedy: Replace the fuse, repair the broken wire or check for poor contact.

　　(2) Stator resistance damage, poor contact of the centrifugal switch

Solution: Repair or replace.

3、The pump shaft can not move

　　(1) Pump head blockage

Solution: Clear the blockage.

　　(2) Pump shaft and bearing wear

Solution: Repair or replace.

　　(3) The impeller collides with adjacent components

Solution: Adjust the gap.

4、The pump does not produce water

　　(1) Insufficient water diversion

Solution: Repair the bottom valve to prevent water leakage or to enhance water diversion.

　　(2) Impeller steering is wrong

Solution: Adjust the motor inlet.

　　(3) Air leakage in the inlet pipe

Solution: Tighten the fasteners or replace the leaking parts.

　　(4) Vacuum is too high

Solution: Reduce vacuuming.

　　(5) Impeller damage

Solution: Replace the impeller.

　　(6) The bottom valve or pipe is blocked

Solution: Clear the blockage.

5、Insufficient flow

　　(1) The lift is too high

Solution: Reduce the lift.

　　(2) Pump or pipe blockage

Solution: Clear the blockage.

　　(3) The impeller port is worn or damaged and should be replaced.

6、The pump vibration has noise

　　(1) The fastening body is loose and should be tightened.

　　(2) The pump shaft should be repaired due to bending.

　　(3) The bearing or impeller should be replaced due to wear of the bearing or impeller.

The faults occurring in the operation of the centrifugal pump are manifested in various forms, and the causes are also various, and the fault phenomena caused by different reasons are often similar, so some fault occurs once in use. The key is to calmly deal with the various causes that may cause failures, from simple to complex, from primary to secondary analysis, to find out the real cause, then the fault is not difficult to rule out (the personnel who conduct fault analysis must have two conditions: It is necessary to have a certain basic knowledge; the second is to have a wealth of practical experience.)