TAIZHOU ZHENDAI ELECTROMECHANICAL CO., LTD.
Common faults and solutions of deep well pumps
来源: | 作者:佚名 | Date :2025-05-04 | 40 次浏览: | Share:

1. Unable to start or difficult to start

Fault performance:

  • The motor is unresponsive or only makes a humming sound after the power is turned on, and cannot run normally.

  • The starting current increases abnormally, causing the fuse to blow or the circuit breaker to trip.

Possible causes:

  • Electrical failure: power supply voltage is too low, phase shortage operation (one phase of the three-phase power supply is disconnected), motor winding short circuit or disconnection.

  • Mechanical failure: pump body jammed (such as impeller stuck by foreign objects), bearing damage, corrosion or deformation of transmission parts.

  • Other factors: start capacitor damage (for single-phase motor), control circuit failure.

Solution:

Electrical check:

  • Use a multimeter to measure the power supply voltage to ensure that the voltage is within the rated range.

  • Check whether the three-phase power supply is balanced, repair broken wires or replace fuses.

  • Test the motor winding resistance, if abnormal need to repair or replace the motor.

Mechanical inspection:

  • Disassemble the pump body and remove foreign matter in the impeller or runner.

  • Check bearing lubrication and replace bearings if necessary.

  • Check whether the transmission parts (such as coupling, belt) are loose or damaged.

Other measures:

  • Replace damaged starting capacitors.

  • Check whether the control circuit (e.g. contactor, relay) is working properly.


2. Insufficient flow or no water during operation

Fault performance:

  • The pump runs with an abnormal sound, but there is no water at the outlet or the flow rate is significantly reduced.

  • The pump head is insufficient to reach the expected pumping height.

Possible causes:

  • Problems with the water source: low water level in the well, clogging of the inlet pipe (e.g. sediment, debris).

  • Pump body failure: impeller wear or damage, guide casing wear, seal ring clearance is too large.

  • Piping problems: leakage in the outlet pipe, valve not fully open, excessive pipe resistance.

Solution:

Water source check:

  • Confirm whether the water level in the well is lower than the suction port of the pump, and reduce the installation depth of the pump if necessary.

  • Clean the inlet piping to remove sediment or debris.

Pump body overhaul:

  • Disassemble the pump body, check the wear of the impeller and guide casing, and replace if necessary.

  • Adjust sealing ring clearance to ensure compliance with design requirements.

Piping inspection:

  • Check whether there is any leakage in the outlet pipe line and repair the leakage point.

  • Ensure that the valve is completely open, reduce pipeline elbows and resistance.


3. Excessive vibration or noise during operation

Fault performance:

  • The pump body runs with obvious vibration, accompanied by abnormal noise.

  • Prolonged operation may lead to the pump body or pipeline loosening.

Possible causes:

  • Installation problems: unstable pump body installation, loose foundation.

  • Mechanical problems: impeller imbalance, bearing damage, drive shaft bending.

  • Hydraulic problem: Cavitation phenomenon (vaporization of liquid due to low inlet pressure).

Solution:

Installation check:

  • Retighten the pump body fixing bolts to ensure a solid foundation.

  • Check the centering of the pump body with the motor and re-center if necessary.

Mechanical overhaul:

  • Perform dynamic balance test on the impeller, repair or replace the unbalanced impeller.

  • Replace damaged bearings, check whether the drive shaft is bent, straighten or replace if necessary.

Hydraulic adjustment:

  • Increase the inlet pressure to avoid cavitation (e.g., reduce the installation depth of the pump).

  • Check whether there is leakage or blockage in the inlet pipeline.


4. Excessive current or motor overheating during operation

Fault performance:

  • The motor running current exceeds the rated value, and the motor casing temperature is too high.

  • Prolonged overload may lead to motor burnout.

Possible causes:

  • Pump body failure: impeller and pump casing friction, bearing damage, packing too tight.

  • Piping problems: clogged outlet pipe, valve not fully open.

  • Electrical problems: power supply voltage is too low, motor winding local short circuit.

Solution:

Pump body overhaul:

  • Check the clearance between impeller and pump casing and adjust to the design value.

  • Replace the damaged bearing and adjust the packing tightness.

Piping inspection:

  • Clean the outlet pipe line and make sure the valve is fully open.

Electrical check:

  • Measure the power supply voltage and make sure it is within the rated range.

  • Check the motor winding resistance, repair or replace the short circuit part.


5. Leakage or drop in insulation resistance

Fault manifestation:

  • Motor casing is energized and insulation resistance test value is below standard.

  • It may lead to electric shock accident or motor damage.

Possible causes:

  • Cable damage: broken cable insulation, water in the joints.

  • Moisture in the motor: water or high humidity inside the motor.

  • Insulation aging: aging of motor winding insulation material.

Solution:

Cable inspection:

  • Check whether the cable insulation is broken, repair or replace the cable.

  • Make sure the cable joints are well sealed to prevent water ingress.

Motor Treatment:

  • Dry the motor to remove internal moisture.

  • Re-impregnate the insulating paint to improve insulation performance.


6. Seal leakage

Failure performance:

  • Fluid leakage from pump body or line connections.

  • May result in lubricant leakage or well water entering the motor.

Possible Causes:

  • Damaged seals: mechanical seals or packing seals are aged and worn.

  • Improper installation: seals are not installed properly or tightened with sufficient force.

Solution:

Replace seal:

Disassemble the seal in the leaking area and replace with a new mechanical seal or packing.

Reinstallation:

  • Ensure that the seal is installed correctly and that the tightening force is even.