How Do I Check If the Motor or Impeller Shaft is Jammed? – Multistage Submersible Pump

TOOLS REQUIRED

• 13mm open-end or ring spanner.
• P2 Phillips head screwdriver.
• Adjustable pliers or soft-jaw grips.
• A clean and stable work surface (workbench or another flat surface).
• Gloves or cloth (if preferred).
• Towel or padding to protect the pump body.

SAFETY FIRST

• Ensure all power sources are off and not providing power to the pump.
• Completely disconnected the pump’s power cable from the pump controller.
• Remove pump from the water source (bore, tank, river, etc.) using the hanging wire. DO NOT pull the pump up by the power cable or water pipe.
• Drain as much water as possible before placing the pump on you work surface.
• Always perform tests in a dry, safe area.

1. Initial Checks

• Locate the water inlet where the pump joins to the motor.
• With the power cable disconnected from the pump controller, attempt to rotate the pump and motor shafts by hand (if accessible).
• A pump shafts should turn freely with a clunking sensation as it is turned. The clunking sensation is the motor shaft’s magnets moving between the windings and is normal.
• If the shaft does not move, feels like it is grinding or grabbing, or there is little to no resistance. Continue to the next step.

2. Separating the pump and motor

• Undo the two screws holding the power cable cover to the pump and lift it away.
• Use a 13mm spanner to remove the four bolts securing the motor to the pump.
• Carefully lift the pump head away from the motor as vertically as possible.

3. Checking the Pump’s Impeller (wet end) Shaft

• Lay the pump (wet end) on your work surface.
• Using fingers or pliers, grip the shaft coupling and rotate it in either direction.
  • Normal movement:
    • The shaft should turn freely with a smooth consistent feel.
    • It should also have some up and down (when vertical) movement.
  • Abnormal movement:
    • The shaft is difficult to turn:
    • Has a grinding or scraping noise/feel to it.
    • Grabs while turning.
    • Is jammed and cannot move.
    • Side to side movement.

3a. Cause of Jamming - Pump

• If the pump’s impeller (wet end) shaft is difficult to turn:
  • A build up debris such as sand, mud, etc. in the impellers is interfering with smooth movement.
  • Sand or other debris has caused damage to the impellers, causing them grind and grab on other surfaces.

• If the pump’s impeller (wet end) shaft cannot be turned:
  • Debris such as mud or grass may have clogged the impellers stages and caused it to jam.

• Sand or other debris has caused damage to the impellers, causing them to grab and jam on other surfaces.
• If the pump’s impeller (wet end) shaft has side to side movement:
  • There are a number of damaged impellers and impeller stages.

4. Checking the Pump’s Motor Shaft

• Using pliers, gently grip the motor shaft and slowly rotate it in either direction.
• A working motor shaft should turn freely with a clunking sensation as it is turned. The clunking sensation is the motor shaft’s magnets moving between the motor’s windings and is normal.
  • Normal movement:
    • The shaft should turn freely with a clunking sensation as it is turned. The clunking sensation is the motor shaft’s magnets moving between the motor’s windings and is normal.
  • Abnormal movement:
    • The shaft is difficult to turn.
    • Has a grinding or scraping noise/feel to it.
    • Grabs while turning.

• Is jammed and cannot move.
• Side to side movement.

4a. Cause of Jamming - Motor

• If the pump’s motor shaft is difficult to turn:
  • The bearings are possibly failing or have failed.
  • Water has gotten into the motor, damaging it internally.
  • The motor shaft has failed and is catching on the other internal components.

• If the pump’s motor shaft cannot be turned:

• The bearings have failed.
• Water has gotten into the motor, damaging it internally.
• If the pump’s motor shaft has side to side movement:
  • The bearings have failed.

DO NOT attempt to reconnect and operate a jammed or failed pump and motor.

Conclusion:

Main causes of jamming:

• Debris such as sand, mud and grass.
• Damaged, failing or failed parts.

Routine inspection every 6–12 months can catch these issues early and keep your pump running smoothly.

For detailed support or to arrange parts or repairs, contact Commodore Australia’s Technical Support team for further assistance.