Xylem LCP - Manual (Page 23)

Installation, Operating and Maintenance Instruction Model LS, LC, LCP
LS 100-english page 21 Revision 02
Artikel No. 771073402 Issue 01/2010
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Cause Solution
Back-pressure too high
check facility for pollution, open discharge valve
reduce resistance in discharge pipe (e.g. clean filter if
necessary)
use larger impeller (note available motor power)
Back-pressure too low, discharge too low throttle discharge valve
Speed too high reduce speed
compare speed of motor with specified pump speed (rating
plate)
when adjusting speed (frequency transformer) check reference
value setting
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
Flow too little increase min. flow (open discharge valve, bypass)
Flow too big reduce flow (throttle discharge valve)
Impeller diameter too big use smaller impeller
Impeller diameter too small use larger impeller (check available motor power)
Pump and/or pipes not completely filled with liquid fill
vent
Pump or suction/intake pipe blocked clean
Air pocket in pipeline vent
improve course of pipe
Suction height too big / NPSH of system too small
increase liquid level and admission pressure
reduce resistance in the intake/suction pipe (change course
and rated width, open shut-off valves, clean filters)
Air being sucked in increase liquid level
check if suction pipe is vacuum-tight
Air being sucked in through shaft sealing clean sealing pipe
increase sealing pressure
replace shaft sealing
Direction of rotation is wrong swap over two phases of power supply (to be done by an
electrician)
Inner components suffering from wear replace worn parts
Density and/or viscosity of liquid handled is too high seek assistance
Stuffing box not straight tighten evenly
Stuffing box is fastened too tight resp. shaft sealing is worn loosen stuffing box
replace packing and/or mechanical seal
check sealing, flushing and cooling pipes (pressure)
avoid dry running
Lines and roughness on shaft or shaft sleeve replace parts
Unsuitable packing material use suitable material (check shaft or shaft sleeve for damage
beforehand)
Deposits on mechanical seal clean
replace mechanical seal if necessary
if necessary provide additional rinsing or quench
Impeller out of balance remove blocks/deposits
replace impeller if broken or unevenly worn
check shafts to ensure that they are running true
Coupling not aligned align pump unit better
Coupling distance too small change
Forces in pipeline too high (pump unit under strain) change (support pipes, use compensators, etc.)
is foundation plate/frame properly cast in place?
Too much, too little or the wrong type of lubricant change
Electricity supply not right (2-phase running) check voltage of all phases
check cable connections and fuses
Sealing insufficient tighten screws
replace sealing
Bearing damaged replace
check lubricant and bearing space for pollutants (rinse oil area)
Relief fittings insufficient
clean relief openings in impeller
replace worn parts (impeller, split rings)
adjust in line with the system pressure/intake pressure given on
ordering
System-related vibrations (resonance) seek assistance