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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:

Problem

Possible Cause

Remedy

Motor Operational but No Fluid Delivery

Direction of Rotation

Check the direction of rotation is in line with arrow on casing and   nameplate

Air pocket in suction line

Ensure suction line filled with fluid, pipework slopes upwards, no kinks in the suction line and pipework is as straight as possible.

Relief Valve Failure

Clean Relief Valve. Check pressure setting. Recalibrate

Check Valve Jammed

Clean check valve. Check operation

Air Ingress through Seal

Check seals for air ingress, all pipework, and connected gaskets.   Check pump O Rings. Replace the pump seal if necessary.

Insufficient Capacity

Relief Valve Opening or Jammed

Check relief valve settings. Recalibrate. Check and clean as a plug may have formed or solid entered jamming open.

Air Ingress

Check seals for air ingress, all pipework, and connected gaskets.   Check pump O Rings. Replace the pump seal if necessary.

Low NPSH

Shorten and enlarge suction line diameter. Deepen suction pipe,   increase tank contents, reduce pump speed and check fluid viscosity against   pump design

Pump Worn

Check internal lobe spacing. Replace lobes

Check Valve Jammed

Clean check valve. Check operation

Pump Noisy

Pump Cavitating

Increase pipework diameter. Reduce suction head. Check fluid viscosity. Clean filters. Reduce pump speed. Increase fluid level in the tank.

Lobe / Rotor Damage

Check lobes and replace if necessary

Misalignment

Realign Pump. Check coupling and rubber

Vibration in safety valve

Increase pressure setting or replace

Positive Displacement Pump Repair

As the leading European supplier of positive displacement pumps we are experts in their repair

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Pump Repair

AxFlow are one of the UK's leading pump repairs and offer local support across the country from our 5 regional bases.

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PD Pumps Team
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