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Problem
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Possible Cause
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Remedy
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Low Pressure
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Worn Nozzle
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Check nozzle for wear. Do not adjust regulating valve as can lead to pump damage.
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Air Leak
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Check suction and discharge pipework for leaks. Use bonding sealant for connections where possible
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Pressure Gauge
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Gauge could be worn, or have particle ingress.
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Relief Valve / Regulator Issue
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Check settings cover system performance. If the system is outside of the range the valves will not function correctly.
Check for ingress of solids.
Check internal parts and piston stems. Reset Primary valve and relief valve.
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Seats or Valves Worn
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Replace as required
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Suction Filter Clogged
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Clear Suction Strainer
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Insufficient NPSH Available
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Suction pressure is incorrect meaning the pump is cavitating. Ensure all valves are open, check the liquid temperature. To correct increased fluid in the tank, check for air ingress, remove unnecessary bends, increase pipe diameter, install feed pump.
A flexible hose is recommended to be 3”-6” before pump inlet.
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Leakage
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Check pipework connections
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Belt
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Check belt teeth, belt tension and belt type
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Noisy Pump
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Knocking Sound
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Worn bearings or loose connecting rods. Service drive end as soon as possible.
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Suction Sound
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NPSH requirements are not being met.
Ensure all valves are open, check the liquid temperature. To correct increased fluid in the tank, check for air ingress, remove unnecessary bends, increase pipe diameter, reduce fluid temperature, install feed pump.
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Screeching Sound
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Belt slippage. Check belt tension & belt wear.
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Oil Leak
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Worn Crankcase Oil Seals
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Replace more frequently when bearings and crankshaft oil seals are replaced
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Worn Crankshaft Oil Seals
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Oil contaminated. Ensure seals are replaced with bearing replacement
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Bearing Wear
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Bearings can be worn by crankcase oil. Seal and packing wear results in liquid traveling along plunger rod allowing oil and water mix. Replace bearing as soon as oil leak is noticed.
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Plunger or Piston Wear
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Replace plunger and pistons. Increase frequency of seal service to reduce plunger or piston wear
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Drain Plug / Oil Gauge Leaking
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Check tightness. Ensure O rings are replaced on the drain plug and oil gauge
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Pulsation
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Insufficient NPSH Available
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Suction pressure is the incorrect meaning pump is cavitating. Ensure all valves are open, check the liquid temperature. To correct increased fluid in the tank, check for air ingress, remove unnecessary bends, increase pipe diameter, reduce fluid temperature, install feed pump.
A flexible hose is recommended 3-6” at the pump inlet.
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Inlet or Discharge Valves worn / sticking
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Check liquid viscosity, lubricity, and presence of particles. Seal flushing may be required in between operations.
NPSH requirements are not being met. Check PH of liquid is between 5-9.
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Discharge Pipework
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Ensure flexible hose is on the inlet of the pump and pulsation dampener fitted on the discharge of the pump.
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Seals or Cups
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Scored Plungers
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Check for Chemical wear, hard water, and abrasive particles. Increase service intervals as high wear to low and high-pressure seals can cause the male adapter to come into contact with the plunger.
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Scored Cylinders or Sleeves
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Cups worn causing damage to cylinders and sleeve. Increase service interval of cups and replace cylinders and sleeves
Sleeves and rods must always be smooth otherwise they will prematurely wear any seals.
Cups and seals should be replaced when a drop in pressure is noticed
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Inlet pressure too High
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Maximum inlet pressure for piston pumps is 40psi (2.75 bar) and plunger pumps is 60-70psi (4-4.8bar). K Style pumps can accept higher inlet pressures.
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High Fluid Temperature
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Check liquid is in line with pump handling capability. Fluid heating may occur from prolonged operation in bypass mode.
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Pump Dry Running
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Check Fluid level and that NPSHR is being met. Check inlet pipework, and filters for blockage, long suction lines, and presence of air ingress
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Seals Installed Incorrectly
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Seals will not hold pressure if installed incorrectly.
Keep V Groove on the spring side or packings towards liquid or high-pressure side.
NBR or FPM cups assembly must be towards liquid or high-pressure side.
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Water in Crankcase
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Spraying / Air Condensation
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Protect pump from direct spray with ventilated enclosure if necessary. Contaminated oil will damage bearings and other components within the drive.
Change oil every 3 months or after 500 hours.
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Worn Seals or V Packings
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This can allow fluid to travel along the plunger rod leading to the scoring of the oil seal allowing the water and oil to mix.
Increase service intervals
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Water Leak
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Worn Seals or V Packings
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Seals wore and require replacing.
The symptom is low pressure. Can be caused by chemical incompatibility, excessive pressure and temperatures
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Worn Sleeves or Cylinders
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Increase frequency of replacement and ensure O ring on piston do not allow water ingress which can cause further damage
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Worn Adaptor
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Split manifold designs of pumps have adapters within the pumps. Check O rings when servicing seals and valves and replace them as required.
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Damaged Plunger
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Can be caused by Thermal Shock, Chemicals or abrasives. Worn packings can allow the male adaptor to travel along the plunger causing damage to it. Examine plunger when installing seals and replace if needed
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Manifold Wear / Damage
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Check chemical compatibility of fluid and any cleaning fluids used. Operation with worn seals and o rings can accelerate manifold wear. Erosion can be limited by freshwater flushing between pump use.
Manifolds can be damaged by overpressure which may be caused by high inlet pressure, relief valve or regulating valve failure or blockage within the pump.
Ensure an external relief valve is installed in the system with an internal relief valve and regulating valve.
If the pump is to be stored for long periods, ensure the pump is drained and filled with 50% water and glycol mix.
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