FP USER INSTRUCTIONS ENGLISH 71576286 - 07/06
Page 26 of 35
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 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 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) CONSULT FLOWSERVE
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 gland packing on the shaft
- Check and replace all the gland packing 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
Misalignment
- Check the alignment of the pump and of its driver
Foundations not sufficiently 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 box according 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 in the 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 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
