A-7: Troubleshooting Guide - Liquiflo H-Series Installation Operation & Maintenance

Liquiflo Installation, Operation & Maintenance Manual
Appendix 7: Troubleshooting Guide
Problem
No discharge
Insuffiecient
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
Pump worn or damaged
Magnetic coupling has decoupled
Suction pressure too low
Bypass valve open
Partly clogged strainer
Speed too low
Pump 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
Differential pressure greater than
specified
Gear clearances insufficient for
fluid viscosity
Plastic gear clearance insufficient
for fluid temperature
Rotating parts binding or severely
worn
H&3-Series MAG-DRIVE Gear Pumps
Models H1F-H9F, 31F-39F & 311F
Corrective Action
Verify suction pipe is submerged.
Increase suction pressure.
Open suction valve.
Reverse motor leads or reverse suction
and discharge piping.
Open all suction and discharge valves.
Close bypass valve.
Tighten connections.
Apply sealant to all threads.
Verify suction pipe is submerged.
Clean strainer.
Rebuild pump.
Stop driver and check temperature and
viscosity of fluid.
Verify position of outer magnet.
Stronger magnetic coupling may be
needed.
Increase suction pressure.
Verify suction piping is not too long.
Fully open any suction valves.
Close bypass valve.
Clean strainer.
Increase driver speed, if possible.
Use larger size pump, if required.
Rebuild pump.
Reprime pump.
Tighten connections.
Apply sealant to all threads.
Inspect gaskets, if applicable.
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.
Increase pipe diameter.
Decrease pipe run.
Purchase gears trimmed for the correct
viscosity.
Purchase plastic gear trimmed for the
correct temperature.
Disassemble pump and replace worn
parts.
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