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Megamachines

Dismantling and Assembly

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General Information

Follow these instructions if it is necessary to dismantle the pump, either because it is clogged or damaged.

Before dismantling

  • Disconnect the electricity supply to the motor.
  • Close the isolating valves, if fitted, to avoid draining the system.
  • Remove the electric cable in accordance with local regulations.

Before assembly

  • Order the necessary service kits.
  • Clean and check all parts.
  • Replace defective parts by new parts.
  • Always replace gaskets and O-rings when the pump is serviced.

During assembly

  • Lubricate and tighten screws and nuts to correct torque.

Dismantling

  1. Remove the nuts from the pump housing.
  2. Remove the pump housing. It may be necessary to use a plastic hammer or a pinch bar for separating the pump housing from the motor stool or cover.
  3. Remove the O-ring from the motor stool/cover.
  4. Hold the impeller with a strap wrench, and slacken the impeller nut. Remove the impeller nut, spring washer and washer from the shaft.
  5. Remove the impeller using a puller.
  6. Remove the key from the shaft.
  7. Remove the spacer rings, if any, between impeller and shaft seal.
  8. Shaft seal, types MG13 and HJ92: ​
    • Pull off the rotating shaft seal part using two screwdrivers
  9. Shaft seal, type M7N:
    • First, pull off the spring retainer using two screwdrivers. Next, remove the seal ring with O-ring using two screwdrivers.
  10. Pump with separate motor stool and clamped cover:
    • Remove the cover.
  11. Pump with separate motor stool and screw-fixed cover:
    • Remove the screws holding cover and motor stool together, and pull off the cover.
  12. Pump with integrated motor stool/cover:
    • Remove the coupling guards and the screws/nuts holding the motor stool and motor together. Remove the motor stool. It may be necessary to loosen the motor stool from the motor with a plastic hammer.
  13. Remove the stationary shaft seal part by pushing it from the back.
  14. Slacken the screws fixing the pump shaft on the motor shaft.
  15. Remove the pump shaft. It may be necessary to loosen it with a pinch bar or similar tool.

Replacing the Wear Rings

Pump with bronze wear rings

  1. Insert the hook of the puller under the wear ring.
  2. Knock the impact block against the puller end stop. Move the puller to another position under the wear ring.
  3. Knock the new wear ring home using a piece of wood as a buffer.
  4. Repeat steps 1 to 3 for the second wear ring of the pump.

Pump with stainless steel wear rings

  1. Unscrew the screws of both wear rings, and remove the wear rings.
  2. Fit new wear rings, and tighten the screws to the correct torque.

Pump with stainless steel/carbon-graphite-filled wear rings

  1. Unscrew the screws of both wear ring retainers, and remove the wear ring retainers.
  2. Push the carbon-graphite-filled wear rings out of the wear ring retainers.
  3. Fit new carbon-graphite-filled wear rings in the wear ring retainers.
  4. Fit the wear rings/wear ring retainers, and tighten the screws to the correct torque.

Assembling the Pump

  1. Lubricate the motor shaft with O-ring grease.
  2. Push the pump shaft home on the motor shaft. Make sure that the pump shaft does not move when you release it.
  3. Apply a drop of Loctite 243 to the set screws, and tighten them into the pump shaft to the correct torque.
  4. Fit the motor stool on the motor.
  5. Fit the screws/nuts on the motor stool, and tighten them to the correct torque.
  6. Fit the mounting bush on the pump shaft.
  7. Pump with separate motor stool and clamped cover:
    • Fit the cover to the motor stool.
  8. Pump with separate motor stool and screw-fixed cover:
    • Fit the cover to the motor stool, and tighten it to the correct torque.
  9. Spray soapy water on the pump shaft and the mounting bush.
  10. Fit the stationary shaft seal part  on the shaft. Do not touch the seal face with your fingers.
  11. Press the stationary shaft seal part home using a punch of soft material.
  12. Shaft seal, types HJ92 and M7N:
    • Remove the screws, if any, from the rotating shaft seal part, and discard them.
  13. Spray soapy water on the rotating shaft seal part.
  14. Press the rotating shaft seal part home using a punch of soft material.
  15. Fit spacer rings, if required, between shaft seal and impeller on the pump shaft.
  16. Remove the mounting bush from the pump shaft.
  17. Fit the key and the impeller on the shaft.
  18. Fit the washer, spring washer  and impeller nut .
  19. Hold the impeller with a strap wrench, and tighten the impeller nut to the correct torque.
  20. Fit the O-ring on the cover, and lubricate it.
  21. Fit the pump housing.
  22. Fasten the cover/motor stool on the pump housing by cross-tightening the nuts to the correct torque.
  23. Check that the pump shaft can rotate freely.
  24. Fit the coupling guards, and tighten the screws to the correct torque.