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7 faults; causes and remedies – HP FM Centrifugal Pump PCN=71576526 User Manual

Page 27

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FM USER INSTRUCTIONS ENGLISH 71576526 - 03/07

Page 27 of 32

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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 in pipes

- Check and deaerate 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 box according 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, back pressure too high)

- Modify the installation or change the pump set

Total manometric head system lower than
pump differential head

- Throttle at discharge valve or trim the impeller (contact our

local agent)

  Pipes (valves, filter...)

- Control, dismantle and clean

  Insufficient flow rate

- Check the suction and discharge pipes (valves, back pressure)

Worn wear -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 mechanical seal

- Check and replace all the mechanical seal parts
- Mechanical seal: CONSULT FLOWSERVE

   

Defective motor bearings

- CONSULT FLOWSERVE

 Specific gravity or viscosity of liquid too high

- Consult our local agent to analyze the problem

Foundations not sufficiently rigid

- Check the setting of baseplates: 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 box according to the

voltage

  Presence of air

- Check and deaerate

Suction pressure insufficient

- Check: the available NPSH > the required NPSH

Mechanical defects

- CONSULT FLOWSERVE

 Air leak in the suction pipe

- Check suction pipe is airtight

 Restriction in suction pipe

- Check diameter of suction pipe

 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

 Obstruction of suction pipe

- Check condition of pipe

 Defective gland packing on the shaft

- Check and replace all the gland packing
- Mechanical seal: CONSULT FLOWSERVE

 Defective gasket

- CONSULT FLOWSERVE