Flowserve MENBLOC 60Hz - Manual (Page 32)

MENBLOC 60Hz USER INSTRUCTIONS ENGLISH 71559945 - 02/13
Page 32 of 36 flowserve.com
The tightening torques have been calculated as a
function of the forces produced by the pumps.
These torques correspond to a tension of the shaft
end of 25 % to 50 % of the elastic limit.
The tolerance allowed on the tightening torques is
±
30 %.
6.6.2 Mechanical seal assembly
The mechanical seal assembly does not need any
particular adjustment. The correct setting is
ensured by a clear support of the mechanical seal
seat on the impeller hub. The stationary seal ring
is set with the help of the tube and the rotating
seal ring, is set with the help of the assembly cone
and the tube.
7 FAULTS; CAUSES AND REMEDIES
Insufficient flow rate
Irregular pump running
Driver overloaded
Mechanical seal leakage
Equipment vibration
Excessive pump casing temperature
Insufficient pressure
Pump looses prime after starting
POSSIBLE CAUSES SOLUTIONS
Pump or suction pipe not completely filled - Check and complete filling
Air bubbles in pipes - Check and de-aerate the pipes
Suction level too low - Check: the NPSHA
>
NPSHR
- Reduce 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 pipe
Wrong rotation - Reverse 2 phases in motor terminal boxes
The motor is running on 2 phases only - Check the motor electrical power supply
Motor running too slow - Check the connection in the terminal box according to
the supply voltage
Total system head 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 system head system lower than pump
differential head -Throttle at discharge valve or trim the impeller:
CONSULT FLOWSERVE
Obstructed or choked pipes or fittings
(valves filter...) - Check, dismantle and clean if necessary
Insufficient flow rate - Check the suction and discharge pipes (valves, back
pressure)
Worn wear-ring surfaces - Replace worn parts: CONSULT FLOWSERVE
Seizure, jamming - Dismantle, check and repair pipe strain: CONSULT
FLOWSERVE
Excessive pipe strain on flanges - Check the flange connections and eliminate strains
(pipe positioning or flexible pipe connection)
Defective mechanical seal - Check and replace all the mechanical seal parts (never
run dry)
Defective motor bearings - CONSULT FLOWSERVE
Specific gravity or viscosity of liquid too high - Check pump selection
- Consult our local agent to analyze the problem
Mechanical defects - CONSULT FLOWSERVE
Air leak in the suction pipe - Check suction pipe is airtight
Restriction in suction pipe - Check diameter of suction pipe
Obstruction of suction pipe - Check condition of pipe
Defective gasket - CONSULT FLOWSERVE