Lobe Pump Fault Diagnosis
If you are experiencing issues with your Lobe Pump, the below guide can help you diagnose any issues, or speak to one of our Technical Sales Engineers for further assistance:
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Problem
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Possible Cause
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Remedy
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Motor Operational but No Fluid Delivery
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Direction of Rotation
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Check the direction of rotation is in line with arrow on casing and nameplate
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Air pocket in suction line
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Ensure suction line filled with fluid, pipework slopes upwards, no kinks in the suction line and pipework is as straight as possible.
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Relief Valve Failure
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Clean Relief Valve. Check pressure setting. Recalibrate
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Check Valve Jammed
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Clean check valve. Check operation
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Air Ingress through Seal
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Check seals for air ingress, all pipework, and connected gaskets. Check pump O Rings. Replace the pump seal if necessary.
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Insufficient Capacity
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Relief Valve Opening or Jammed
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Check relief valve settings. Recalibrate. Check and clean as a plug may have formed or solid entered jamming open.
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Air Ingress
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Check seals for air ingress, all pipework, and connected gaskets. Check pump O Rings. Replace the pump seal if necessary.
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Low NPSH
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Shorten and enlarge suction line diameter. Deepen suction pipe, increase tank contents, reduce pump speed and check fluid viscosity against pump design
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Pump Worn
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Check internal lobe spacing. Replace lobes
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Check Valve Jammed
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Clean check valve. Check operation
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Pump Noisy
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Pump Cavitating
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Increase pipework diameter. Reduce suction head. Check fluid viscosity. Clean filters. Reduce pump speed. Increase fluid level in the tank.
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Lobe / Rotor Damage
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Check lobes and replace if necessary
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Misalignment
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Realign Pump. Check coupling and rubber
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Vibration in safety valve
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Increase pressure setting or replace
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