Troubleshooting

In this section, you will find a wide range of troubleshooting for Comet diaphragm and high pressure plunger pumps. If you have further questions in regards to troubleshooting your Comet pump, please reach out to our team at 800-864-1649 or send us an email via our Contact page.

Diaphragm Pump Troubleshooting

Diaphragm Pump Doesn't Charge + -
  • Air Inlet – Check inlet for blockage
  • Regulation Valve Closed Control Group Not At Zero – Position the lever
  • Valve or Site of Inlet Valve & Delivery Worn or Dirty  Replace or clean
Diaphragm Pump Doesn't Reach The Desired Pressure + -
  • Worn Valve or Sit of Regulation Valve – Replace or clean
  • Valve or Site of Inlet Valve & Delivery Worn or Dirty – Replace or clean
  • Insufficient RPM’s Bring the  RPMs to 350-550
  • Worn Nozzles Used or Holes Too Big Replace
Pressure Irregular Or With A Pulse + -
  • Valve or Site of Inlet Valve & Delivery Worn or Dirty – Replace or clean
  • Air Inlet – Check inlet for blockage
Excessive Diaphragm Vibrations + -
  • Pressure Accumulator Discharged Or With Incorrect Air Pressure – Bring air to correct pressure
Water Present In Oil + -
  • Broken Diaphragm – Drain oil, clean internal parts, replace with new diaphragm and fill with new oil.  Be sure to eliminate air bubbles from crankcase
  • Air Bubble In Crankcase –  After refilling with new oil, it is imperative to turn the crankshaft while rocking the pump side to side and in all directions if possible, without spilling oil.  The more diaphragms a pump has, the more this needs to be done in order to purge ALL air bubbles out of the new oil before restarting.  Failure to do so will result in an immediate diaphragm failure, or white oil despite no diaphragm failure.

Plunger Pump Troubleshooting

Comet Plunger Pump Does Not Start + -
  • Air Suction – Check the control inlet device.
  • Closed Lance – Check and open the lance.
Irregular Pressure Vibration For Plunger Pump + -
  • Pump Sucking Air – Check that there is no water leaking as it enters pump.
  • Nozzle Inadequate or Worn – Clean or replace nozzle.
  • Worn or Dirty/Blocked Valves – Replace check valves.
Drop In Pressure With Plunger Pump + -
  • Worn Nozzle – Replace nozzle.
  • Worn or Dirty/Blocked Valves – Replace check valves.
  • Worn Packing – Install new seal kit.
Excessive Noise From Plunger Pump + -
  • Pump Sucking Air – Check that there is no water leaking as it enters pump.
  • Blocked Suction – Inspect filter and inlet supply
  • Water Temperature is Too Hot – Max water temperature must not exceed 145° F
  • Worn or Dirty/Blocked Valves – Replace check valves.
  • Worn Bearings – Replace bearings.
Oil Leak In Plunger Pump + -
  • Oil Seal Worn – Install new oil seals.