Faults - Causes And Solutions - Xylem MPVN Manual De La Instrucción

7. FAULTS – CAUSES AND SOLUTIONS
The following notes on causes of faults and how to
repair them are intended as an aid to recognizing the
problem. The distributor's Customer Service Department
is available to help repair faults that the operator cannot
or does not want to repair. If the operator repairs or
changes the pump, the design data on the Data Sheet and
Points 1.2 – 1.4 of these Operating Instructions should be
particularly taken into account. If necessary, the written
agreement of the distributor must be obtained.
FAULTS
DISCHARGE TOO LOW
Code no. 1, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
DISCHARGE STOPS AFTER A TIME
Code no. 8, 10, 11, 12, 30
HEAD TOO LOW
Code no. 2, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 30, 34
HEAD TOO HIGH
Code no. 3, 5, 34
DRIVE MECHANISM OVERLOADED
Code no. 2, 3, 5, 15, 25, 27
PUMP NOT RUNNING QUIETLY
Code no. 7, 10, 14, 22, 23, 24, 25, 29, 30, 33
TEMPERATURE IN THE PUMP TOO HIGH
Code no. 7, 10, 30
TEMPERATURE IN THE SHAFT SEALING TOO
HIGH
Code no. 18, 19, 21
TEMPERATURE AT THE BEARING TOO HIGH
Code no. 2, 14, 23, 24, 25, 26, 29, 31, 32
PUMP LEAKING
Code no. 25, 28
LEAKAGE RATE AT SHAFT SEALING TOO HIGH
Code no. 19, 21, 22, 25
MEANING OF CODE NUMBER FOR CAUSE AND
METHOD OF REPAIR
1. Back-pressure too high
• open discharge valve further
• reduce resistance in discharge pipe (e.g. clean filter if
necessary)
• Use larger impeller (note available motor power)
2. Back-pressure too low, discharge too low
• throttle discharge valve
3. Speed too high
• reduce speed
• compare speed of motor with specified pump speed
(rating plate)
• when adjusting speed (frequency transformer) check
reference value setting
4. Speed too low
• increase speed (check available motor power)
•compare speed of motor with specified pump speed
(rating plate)
• when adjusting speed (frequency transformer) check
reference value settings
5. Impeller diameter too large
• use smaller impeller
6. Impeller diameter too small
• use larger impeller (check available motor power)
7. Pump and/or pipes not completely filled with liquid
• fill
• vent
8. Pump or suction/intake pipe blocked
• clean
9. Air pocket in pipeline
• vent
• improve course of pipe
10. NPSH of system too small
• increase liquid level
• increase admission pressure
• reduce resistance in the intake/suction pipe (change
course and rated width, open shutoff valves, clean
filters)
11. Air being sucked in
• increase liquid level
• check suction pipe is vacuum-tight
• provide straightening vanes in suction pipe fittings with
water seal
12. Air being sucked in through shaft sealing
• clean sealing pipe
• increase sealing pressure
• replace shaft sealing
13. Direction of rotation is wrong
• swap over two phases of power supply (to be done by
a specialist electrician)
14. Inner components suffering from wear
• replace worn parts
15. Density and/or viscosity of liquid handled is too high
• seek assistance
16. Shaft sealing worn
• check sealing, flushing and cooling pipes (pressure)
• avoid dry running
17. Lines and roughness on shaft or shaft sleeve
• replace parts
18. Deposits on mechanical seal
• clean
• replace mechanical seal if necessary
• if necessary provide additional rinsing or quench
19. Impeller out of balance
• remove blocks/deposits
• replace if broken or unevenly worn
• check shafts to ensure that they are running true
20. Coupling not aligned
• align pump unit better
21. Coupling distance too small
• change
22. Forces in pipeline too high (pump unit under strain)
• change (support pipes, use copensators, etc.)
• is foundation plate/frame properly cast in place?
23. Too much, too little or the wrong type of lubricant
• change
24. Electricity supply not right
• check voltage of all phases (2-phase running)
• check cable connections
• check fuses
25. Sealing insufficient
• tighten screws
• replace sealing
26. Bearing damaged
• replace
• check lubricant and bearing cavity for pollutants (clean
grease cavity if needed)
27. Discharge too small
• increase min. amount carried (open slide valves, bypass)
28. Discharge too high
• reduce amount carried (throttle slide valve)
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