Faults; Causes And Remedies - Flowserve FM Centrifugal Pump PCN=71576526 User Instructions

7 FAULTS; CAUSES AND REMEDIES

POSSIBLE CAUSES
    Pump or suction pipe not completely filled
    Air bubbles in pipes
   Suction level too low
  Wrong rotation
  
The motor is running on 2 phases only

Motor running too low
 
Total manometric head system higher than
pump differential head
 
Total manometric head system lower than
pump differential head
   Pipes (valves, filter...)
  Insufficient flow rate

Worn wear-ring surfaces
   
Seizure, jamming
   
Excessive strains on flanges

Defective mechanical seal
   
Defective motor bearings
  Specific gravity or viscosity of liquid too high

Foundations not sufficiently rigid
POSSIBLE CAUSES

Rotation speed too low (check the driver)
  Presence of air

Suction pressure insufficient

Mechanical defects
 Air leak in the suction pipe
 Restriction in suction pipe
 Suction level too low
 Obstruction of suction pipe
 Defective gland packing on the shaft
 Defective gasket
Page 27 of 32
FM USER INSTRUCTIONS ENGLISH 71576526 - 03/07
Insufficient flow rate
Irregular pump running
Driver overloaded
Mechanical seal leak
Equipment vibration
Excessive pump casing temperature
SOLUTIONS
- Check and complete filling
- Check and deaerate the pipes
- 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
- Reverse 2 phases on motor terminal boxes
- Check and control the motor electrical power supply
- Check the connection in the terminal box according to the
voltage
- 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
- Throttle at discharge valve or trim the impeller (contact our
local agent)
- Control, dismantle and clean
- Check the suction and discharge pipes (valves, back pressure)
- Foresee pump mending: CONSULT FLOWSERVE
- CONSULT FLOWSERVE
- Check the flange connections and eliminate strains (pipe
positioning or elastic sleeves mounting)
- Check and replace all the mechanical seal parts
- Mechanical seal: CONSULT FLOWSERVE
- CONSULT FLOWSERVE
- Consult our local agent to analyze the problem
- Check the setting of baseplates: tightening, bad adjustment,
seal
Insufficient pressure
Pump looses prime after starting
SOLUTIONS
- Check the connection in the terminal box according to the
voltage
- Check and deaerate
- Check: the available NPSH > the required NPSH
- CONSULT FLOWSERVE
- Check suction pipe is airtight
- Check diameter of suction pipe
- 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
- Check condition of pipe
- Check and replace all the gland packing
- Mechanical seal: CONSULT FLOWSERVE
- CONSULT FLOWSERVE
flowserve.com