Omega
36
11.2
Trouble--shooting Table
Pum
p
pressure
too
low
P
um
p
pr
essur
e
too
high
Flow
rate
too
high
Flow
rate
too
low
Pow
er
consum
ption
too
high
P
um
p
fa
ils
to
pum
p
liqui
d
af
ter
bei
ng
sw
itc
hed
on
Pum
p
ceases
to
pum
p
liquid
Pum
p
does
not
run
sm
oothly
(noise,
vibrations)
Inadm
issible
tem
perature
increase
at
pum
p
/
seal
casing
Bearing
tem
perature
too
high
E
xessive
leakage
at
shaft
seal
D
rive
overloaded
Leakage
at
pum
p
Cause
Remedy
1)
F
F
F
F
F
F
F
F
F
Operating point B does not
lie at the calculated inter-
sections of Q and H
Re--adjust operating point
F
Pump or piping incomple-
tely vented or not primed
Vent.
F
F
F
F
F
F
Suction pipe or impeller
blocked
Clean impeller
Check plant for impurities
Remove deposits in pump and / or piping
Check strainer / suction opening
F
F
F
Formation of air pockets in
the piping
Correct suction conditions
Alter piping
F
F
F
F
F
Suction head too high
(NPSH
available
too low) /
water level too low
Check mode of operation
Correct suction conditions
Increase positive suction head
Increase back pressure by throttling
Install pump at a lower level
Alter intake pipe if resistances are too high
F
F
F
F
Air is drawn in at shaft seal Clean sealing liquid line, possibly introduce
sealing liquid from an external source or
increase pressure
Check level of liquid in feed tank
Replace shaft seal
Replace shaft protecting sleeve
F
F
F
F
F
Wrong direction of rotation Interchange two phases of the power cable
Check electrical connections
Check impeller position, correct if neces-
sary
F
F
F
Speed too low
Increase speed
1)
,
Check switchgear,
Fit larger impeller
1)
.
F
F
F
F
Internals worn
Check duty point / pump selection
Increase back pressure by throttling
Check medium handled for contamination
by chemicals and solids content
Replace worn components
F
F
Pump pressure is lower
than specified in the order
Re--adjust operating point
Increase back pressure by throttling.