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Priming System Troubleshooting

  • Drain Valve should be shut and plugs secured.
  • Non-Return Valve on discharge should be checked to see if it seats properly and is not obstructed or damaged.
  • Compressed Air Line hose should be free from kinks, crushing and internal obstructions.
  • Test the Check Valve’s internal spring for operation and examine any carbon buildup.
  • Replace compressor air filters if damaged. Clean with compressed air from inside out if dirty.
  • Check the Compressor Pressure Relief Valve by pulling the ring with a light force to check that the internal plunger operates freely. It is set to release at 125 psi. Replace if damaged.
  • Evidence of internal wear on the Venturi Jet and Nozzle should be checked, as it will seriously affect priming performance. O-rings should be checked for wear and damage and replaced if necessary.
  • Check your Separation Tank Cover / Ball Seat Fit as these threads are potential leak points and can cause prime to be lost.
  • Damage to the 1” Separation Tank Cover Priming Ball will adversely affect priming performance.

What if your pump does not prime? Possible causes:

  • Trying to lift water too far up to pump (25’ is a realistic maximum at sea level - altitude will limit this).
  • Insufficient water in suction hose inlet.
  • Suction inlet or strainer blocked.
  • Suction line has a vacuum leak.
  • Collapsed suction hose.
  • Pump non-return valve is not closing due to wear / debris.
  • Air leak in pump assembly (check suction hose and front cover gaskets, ball valves open, dowty washers / bolts, mechanical seal).
  • Compressor belt broken / not driven / compressor not rotating.
  • Compressor valve failure.
  • Pressure relief valve failed / missing.
  • Compressor pipe leaking air or plugged.
  • Engine and compressor speed too low for required lift.
  • If running with a flooded suction and a disabled priming system the volute may be airlocked.

My Pump appears to prime but nothing comes out of discharge line:

  • If pumping up and over an embankment the discharge piping may be airlocked.
  • Closed valve in the discharge line.
  • Either fault is potentially very hazardous and the system should be shut down until the fault is found and rectified.