During the maintenance process, the diagnosis of the pump fault is a very important link. The following gives several common faults and elimination measures for everyone to target the pump fault diagnosis.

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

    1) No water injection or proper exhaust, elimination measures: check whether the pump casing and the inlet pipeline are completely filled with liquid.

    2) The speed is too low, and elimination measures: check whether the wiring of the motor is correct, the voltage is normal or the steam pressure of the turbine is normal.

    3) The water head of the system is too high. Elimination measures: check the water head of the system (especially the friction loss).

    4) The suction stroke is too high, elimination measures: check the existing net pressure head (the inlet pipeline is too small or too long will cause a large friction loss).

    5) The impeller or pipeline is blocked, and elimination measures: check for obstacles.

    6) The direction of rotation is wrong, and elimination measures: check the direction of rotation.

    7) Air is generated or there is a leak in the inlet pipeline. Elimination measures: Check the inlet pipeline for cavitation and air leakage.

    8) The packing or seal in the stuffing box is worn, causing air to leak into the pump casing. Elimination measures: check the packing or seal and replace as necessary, and check whether the lubrication is normal.

    9) Insufficient suction head when pumping hot or volatile liquids, elimination measures: increase suction head, consult the manufacturer.

    10) The bottom valve is too small, eliminate measures: install the correct size of the bottom valve.

    11) The immersion depth of the bottom valve or inlet pipe is not enough. Elimination measures: Consult the manufacturer for the correct immersion depth. Use baffles to eliminate eddy currents.

    12) The impeller clearance is too large, eliminate measures: check whether the clearance is correct.

    13) Impeller damage, elimination measures: check the impeller and replace it as required.

    14) The impeller diameter is too small, elimination measures: consult the manufacturer for the correct impeller diameter.

    15) The position of the pressure gauge is incorrect. Elimination measures: check the position is correct, check the outlet nozzle or pipeline.

    2. The pump will stop after a while

    1) The suction stroke is too high, elimination measures: check the existing net pressure head (the inlet line is too small or too long will cause a large friction loss).

    2) The impeller or pipeline is blocked, and elimination measures: check for obstacles.

    3) Air is generated or there is a leakage in the inlet pipeline. Elimination measures: Check the inlet pipeline for cavitation and/or air leakage.

    4) The packing or seal in the stuffing box is worn, causing air to leak into the pump casing. Elimination measures: check the packing or seal and replace as necessary. Check whether the lubrication is normal.

    5) Insufficient suction head when pumping hot or volatile liquids, elimination measures: increase suction head, consult the manufacturer.

    6) The immersion depth of the bottom valve or inlet pipe is not enough, and elimination measures: consult the manufacturer for the correct immersion depth, and use the baffle to eliminate the vortex.

    7) Damaged pump casing gasket, elimination measures: check the condition of the gasket and replace it as required.

    3. The pump power consumption is too large

    1) The direction of rotation is wrong, and elimination measures: check the direction of rotation.

    2) Impeller damage, elimination measures: check the impeller and replace it as required.

    3) Rotating parts bite and eliminate measures: Check whether the clearance of internal wear parts is normal.

    4) Shaft bending, elimination measures: straighten the shaft or replace it as required.

    5) If the speed is too high, eliminate measures: check the winding voltage of the motor or the steam pressure delivered to the turbine.

    6) The water head is lower than the rated value. Excessive liquid pumping, elimination measures: Consult factory. Install the throttle valve and cut the impeller.

    7) The liquid is heavier than expected. Elimination measures: check specific gravity and viscosity.

    8) The stuffing box does not have the correct packing (insufficient packing, incorrect stuffing or running-in, the packing is too tight), elimination measures: check the packing and refill the packing box.

    9) Incorrect bearing lubrication or bearing wear, elimination measures: check and replace as required.

    10) The running gap between the wear rings is incorrect. Elimination measures: Check whether the gap is correct. Replace the wear ring of the pump casing and/or impeller as required.

    11) The stress on the pipeline on the pump casing is too large, and the measures to eliminate it: eliminate the stress and consult with the manufacturer's representative. After removing the stress, check the alignment.

    4. The stuffing box leaks too much

    1) Shaft bending, elimination measures: straighten the shaft or replace it as required.

    2) Misalignment of the coupling or the pump and the driving device. Elimination measures: Check the alignment and re-align if necessary.

    3) Incorrect bearing lubrication or bearing wear, elimination measures: check and replace as required.

    5. Bearing temperature is too high

    1) Shaft bending, elimination measures: straighten the shaft or replace it as required.

    2) Misalignment of the coupling or the pump and the driving device. Elimination measures: Check the alignment and re-align if necessary.

    3) Incorrect bearing lubrication or bearing wear, elimination measures: check and replace as required.

    4) The stress on the pipeline on the pump casing is too large, and measures to eliminate it: eliminate the stress and consult the manufacturer's representative. After removing the stress, check the alignment.

    5) Too much lubricant, elimination measures: remove the plug to allow excess grease to drain out automatically. If it is an oil-lubricated pump, drain the oil to the correct oil level.

    6. Packing box overheating

    1) The packing or seal in the stuffing box is worn, allowing air to leak into the pump casing. Elimination measures: check the packing or seal and replace as necessary. Check whether the lubrication is normal.

    2) The stuffing box does not have the correct packing (insufficient packing, incorrect stuffing or running-in, packing too tight), elimination measures: check packing, refill packing box.

    3) The packing or mechanical seal has design problems and elimination measures: consult the manufacturer.

    4) Damaged mechanical seal, elimination measures: check and replace as required. Consult the manufacturer.

    5) Shaft sleeve scratches, elimination measures: repair, re-machine or replace as required.

    6) The packing is too tight or the mechanical seal is not adjusted correctly. Elimination measures: check and adjust the packing and replace it as required. Adjust the mechanical seal (refer to the manufacturer's instructions provided with the pump or consult the manufacturer).

    7. Rotating parts are difficult to rotate or have friction

    1) Shaft bending, elimination measures: straighten the shaft or replace it as required.

    2) The running gap between the wear rings is incorrect. Elimination measures: Check whether the gap is correct. Replace the wear ring of the pump casing or impeller as required.

    3) The stress on the pipeline on the pump casing is too large, and the measures to eliminate it: eliminate the stress and consult with the manufacturer's representative. After removing the stress, check the alignment.

    4) Shaft or impeller ring swings too much, elimination measures: check rotating parts and bearings, and replace worn or damaged parts as required.

    5) There is dirt between the impeller and the pump casing wear ring, and there is dirt in the pump casing wear ring. Elimination measures: clean and inspect the wear ring and replace it as required. Cut off and eliminate the source of dirt.