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MHP-TN USER INSTRUCTIONS ENGLISH 71576313 - 02/07
Page 25 of 28 flowserve.com
7 FAULTS; CAUSES AND REMEDIES
Insufficient flow rate
Irregular pump running
Driver overloaded
Mechanical seal leak
Equipment vibration
Excessive pump casing temperature
POSSIBLE CAUSES SOLUTIONS
Pump or suction pipe not completely filled - Check and complete filling
Air bubbles inpipes - Check and desecrate the pipes
Suction level too low - Check: the available NPSH> the required NPSH
- Reduce geometrical suction lift
- Reduce head losses in pipes and in fittings (diameter increase
and appropriate fitting positions)
- Check valves and strainers
- Check the immersion head of the suction valve
Wrong rotation - Reverse 2 phases on motor terminal boxes
The motor is running on 2 phases only - Check and control the motor electrical power supply
Motor running too low - Check the connection in the terminal boxaccording to the
voltage
Total manometric head system higher than
pump differential head
- Check the discharge head
- Check the head losses in discharge pipes (partly closed valve,
foreign particles, backpressure too high)
- Modify the installation or change the pump set
Total manometric head system lower than
pump differential head
-Throttle at discharge valve or trimthe impeller (contact our
local agent): CONSULTFLOWSERVE
Pipes (valves, filter...) - Control, dismantle and clean
Insufficient flow rate - Check the suction and discharge pipes(valves, back
pressure)
Wornwear-ring surfaces - Foresee pump mending. CONSULT FLOWSERVE
Seizure, jamming - CONSULT FLOWSERVE
Excessive strains on flanges - Check the flange connections and eliminate strains (pipe
positioning or elastic sleeves mounting)
Defective gland packing on the shaft - Check and replaceall the gland-packing parts.
- Mechanical seal: CONSULTFLOWSERVE
Defective motor bearings - CONSULT FLOWSERVE
Specific gravity or viscosity of liquid too high - Consult our local agent to analyze the problem
Misalignment - Check the alignmentof thepump and of its driver
Foundations notsufficiently rigid - Check the setting of base plates: tightening, bad adjustment,
seal
Insufficient pressure
Pump looses prime after starting
POSSIBLE CAUSES SOLUTIONS
Rotation speed too low(check the driver) - Check the connection in the terminal boxaccording to the
voltage
Presence of air - Check and de-aerate
Suction pressure insufficient - Check: the available NPSH> the required NPSH
Mechanical defects - CONSULT FLOWSERVE
Air leak inthe suction pipe - Check suction pipe is airtight
Restriction in suction pipe - Check diameter of suction pipe
Suction level too low - Check the NPSH >NPSH
- Reduce geometricalsuction lift
- Reduce head losses in pipes and in fittings (diameter increase
and appropriate fitting positions)
- Check valves and strainers
- Check the immersion head of the suction valve
Obstruction of suction pipe - Checkcondition of pipe
Defective gland packing on the shaft - Check and replace all the gland packing.
- Mechanical seal: CONSULTFLOWSERVE
Defective gasket - CONSULT FLOWSERVE