MHP-TN USER INSTRUCTIONS ENGLISH 71576313 - 02/07

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

- Check the discharge head

 

 

 

 

 

 

 

 

pump differential 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

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

 

 

 

 

 

 

 

 

pump differential head

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

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