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Liquiflo Installation, Operation & Maintenance Manual
Appendix 5: Troubleshooting Guide
Problem
No discharge
Insufficient discharge
Loss of suction after
satisfactory operation
Excessive power
consumption
Troubleshooting Guide – Part 1
Possible Cause
Pump not primed
Wrong direction of rotation
Valves closed
Bypass valve open
Air leak in suction line
Clogged strainer
Clogged impeller
Impeller greatly worn or damaged
Suction pressure too low
Bypass valve open
Partly clogged strainer
Partly clogged impeller
Speed too low
Impeller worn or damaged
Pump not properly primed
Air leaks in suction line
Air or vapor pockets in suction line
Increase in fluid viscosity
Fluid viscosity higher than specified
Liquid specific gravity higher than
expected
Total head greater than specified
Total head lower than specified,
pumping higher flow than expected
Total head higher than rating with flow
at rating
Rotating parts binding or severely worn
Centry
Model 620 – Sealed
Verify suction pipe is submerged.
Increase suction pressure.
Open suction valve.
Reverse motor leads.
Open all suction and discharge valves.
Close bypass valve.
Tighten connections.
Apply sealant to all threads.
Verify suction pipe is submerged.
Clean strainer.
Disassemble and remove blockage.
Disassemble and replace impeller.
Increase suction pressure.
Verify suction piping is not too long.
Fully open any suction valves.
Close bypass valve.
Clean strainer.
Disassemble and remove blockage.
Increase driver speed, if possible.
Use larger size pump, if required.
Disassemble and replace impeller.
Reprime pump.
Tighten connections.
Apply sealant to all threads.
Verify suction pipe is submerged.
Rearrange piping as necessary.
Heat fluid to reduce viscosity.
Reduce pump speed.
Heat fluid to reduce viscosity.
Reduce pump speed.
Increase driver horsepower.
Reduce pump speed.
Increase driver horsepower.
Increase pipe diameter.
Decrease pipe run.
Install throttle valve.
Install impeller with correct diameter.
Disassemble and replace worn parts.
54
®
Series Centrifugal Pumps
Corrective Action
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