How to Replace Mechanical Seals in Centrifugal Pumps

Mechanical seals are used in centrifugal pumps to keep water or any liquid from making contact with the delicate parts of the machine. They are situated on the shaft of the motor. Regular maintenance of these seals is needed to ensure there are no leaks. This article teaches you how to replace the mechanical seal. You will need to purchase a new seal to be able to follow these instructions.

Steps

  1. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 1
    1
    Turn off the power. If the centrifugal motor is in motion, turn it off. Shut off the main power supply. Ensure that there is no possibility of the machine starting up, once you get to work.
  2. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 2
    2
    Cut the plumbing. Cut the plumbing tubes connected to the centrifugal pump. You can use a saw to perform this action. Once disconnected, you are free to set the pump on a table or the floor, wherever you are comfortable.
    Advertisement
  3. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 3
    3
    Disconnect the pump. Using a wrench, unscrew the bolts holding the pump housing in place. Carefully disconnect and detach the pump located beyond the housing. Keep these bolts safe. You will need it later to reattach this setup.[1]
  4. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 4
    4
    Dismantle the centrifugal pump’s impeller. The seal is located on the shaft behind the impeller. To detach the shaft, first hold the shaft in place using a wrench. Then unscrew the impeller by rotating it.
  5. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 5
    5
    Remove the seal. Part of the seal will be attached to the impeller, while the other part will be attached to the motor shaft. Slide the seal off from both these places.
  6. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 6
    6
    Replace the seal. Slide a mechanical seal along the shaft of the motor. Note that the front face of the shaft is extremely sensitive, even to the oils secreted by the fingers. Make sure that you don’t touch the face.[2]
  7. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 7
    7
    Screw on the impeller. With the help of a wrench, hold the motor shaft. Screw on the impeller.[3]
  8. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 8
    8
    Reconnect the pump. Using a wrench and the bolts from Step 3, reattach the pump and the motor.
  9. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 9
    9
    Reconnect the centrifugal pump. Place the reconnected system back into the plumbing. Reconnect the plumbing tubes with the help of industrial strength PVC glue and primer.
  10. Image titled Replace Mechanical Seals in Centrifugal Pumps Step 10
    10
    Restart the machine. After reattaching the plumbing to the centrifugal pump, the PVC glue and primer takes a minimum of one day to dry off completely. Start the machine after a day.
    11. Advertisement

Community Q&A

  • Question
    What clearance should there be between the impeller and the backing plate?
    Community Answer
    Community Answer
    Look on the pump shaft, you usually can see the mark where the set screw was previously. Use the same mark.
  • Question
    Why is it important to ensure mechanical seals are correctly tensioned?
    Community Answer
    Community Answer
    If the tension is too tight, the new seal will not last as long due to more heat from increased friction. Too loose will result in the seal leaking prematurely.
  • Question
    Where can I find a step by step diagram for replacing a seal?
    Community Answer
    Community Answer
    If you are referring to a mechanical seal, then I usually find that if you phone the pump manufacturers and ask nicely, they will usually send out some information to help. You can also search for Vulcan seals on the internet and ask for one of their seal books to be posted to you (they are free).
Advertisement

Warnings

  • Ensure that there is no power supply to the machine when dismantling it.
    ⧼thumbs_response⧽
  • Be sure to wear the right safety gear including industrial grade shoes, hard hats, protective gloves, safety glasses, etc.
    ⧼thumbs_response⧽
Advertisement

You Might Also Like

Detect Water Leaks in Walls
How to
Detect Water Leaks in Walls
How to
Boil Water
Calculate Water Pump HorsepowerHow to Calculate and Measure Water Pump Horsepower
Fix Leaking Pipes
How to
Fix Leaking Pipes
Adjust Pressure SwitchHow to Adjust a Pressure Switch
Turn Water Back on
How to
Turn Water Back on
Soften Hard Water
How to
Soften Hard Water
Troubleshoot Low Water Pressure
How to
Troubleshoot Low Water Pressure
Find a Leak in Your Swimming Pool
How to
Find a Leak in Your Swimming Pool
Dry Water Under Wood Floor
How to
Dry Water Under Wood Floor
Chug Water
How to
Chug Water
Raise the pH of Water
How to
Raise the pH of Water
Ionize Water
How to
Ionize Water
Remove Calcium from Water
How to
Remove Calcium from Water
Advertisement

References

  1. ↑ https://www.youtube.com/watch?v=06KZ3gZcedk
  2. ↑ https://www.youtube.com/watch?v=YXxFKnjsytE
  3. ↑ https://youtu.be/GTmeV_UkU0I?t=270

About This Article

wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, volunteer authors worked to edit and improve it over time. This article has been viewed 48,160 times.
42 votes - 81%
Co-authors: 5
Updated: August 10, 2021
Views: 48,160
Categories: Water
Advertisement