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Instructions for Replacing the Diaphragm Pump

Applicable to the following units:

Step-by-step how to:

  1. Unscrew both nuts which hold the diaphragm crank to the pump handle. Remove both nuts and pressure washers. Lift or pull crank away from the two screws. It is not necessary to remove the aluminum crank from the diaphragm.
  2. Remove clip which holds the pump handle in spray pack.
  3. Slide pump handle slowly to the left, and then slip out the screws from the pump handle completely. Complete sliding of handle to the left and remove completely from spray pack. Be sure not to lose the nylon washers.
  4. Remove hose from sprayer, by removing the 90 degree fitting and hose clamp.
  5. The diaphragm is now exposed and can be removed.
  6. Place a large rubber-band over the circular metal ring that holds the diaphragm together or use a pair of gloves to grip the pump module. Turn the complete diaphragm counter-clockwise until it is totally unscrewed from the spray pack. Discard old diaphragm.
  7. Once the diaphragm has been removed, you will notice a small mark or plastic protrusion, both on the diaphragm and on the spray pack. Look for the marks. These marks are placed here for aligning. When the new diaphragm is put in, these marks must align for proper functioning.
  8. After you have located the markings on the spray pack and the diaphragm, you are ready to reassemble the unit. Place oil on the "O" rings to prevent damage and for easier threading. Place in the proper position and turn clockwise. You will notice a large "O" ring on the diaphragm, continue to turn diaphragm until this "O" ring can no longer be seen. At this time make sure the markings on the diaphragm and the spray pack are aligned.
  9. Take pump handle and put back into spray pack. Make sure the nylon washers are in place. Slide handle in slowly and immediately put screws into screws holes, one at a time. You must get the screws in before you can complete assembly.
  10. Once the screws have been put in place, finish pushing pump handle in the rest of the way. You may now place pin back in place.
  11. Connect the hose by inserting the 90° fitting into its original position and tighten the hose clamp.
  12. Place screws through holes on the aluminum crank. Place pressure washer and nut. Tighten down firmly.
  13. Assembly has been completed.

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