DESMI PUMPING TECHNOLOGY A/S
-11-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: +45 96 32 81 11
Fax +45 98 17 54 99
E-mail:
FAULT
CAUSE
REMEDY
The pump does not
prime
1. The pump is not filled
with liquid
2. Leaking non-return
valve in pump
3. Wrong direction of
rotation
4. Air is drawn in because
of too little liquid or
leaking suction line
5. Liquid lock in outlet
line
6. Temperature of liquid
too high
7. Air cannot escape on
pressure side
Fill pump casing with liquid
Remove foreign body in
valve/Remove any coating
on mating faces
Change direction of rotation
Lower suction pipe/ Tighten
suction line
Change the pressure line so
that the air can pass out
freely
Replace liquid in pump
casing/Wrong dimen-
sioning/Contact DESMI
Ventilate the system
The pump has no or too
low capacity
1. Wrong direction of
rotation
2. Piping system choked
3. The pump is choked
4. Suction line leaks
Pump takes air
5. Suction lift too high
6. Pump and piping system
wrongly dimensioned
Change direction of rotation
to clockwise when viewed
from shaft end (the direction
of the arrow)
Clean or replace
Clean the pump
Find the leakage/repair the
fault, non-return valve not
submerged
Check data sheet Q/H curve
and NPSH or contact
DESMI
As 5
The pump uses too
much power
1. Counter-pressure too
low
2. The liquid is heavier
than water
3. Foreign body in pump
4. Electric motor is
running on 2 phases
Insert orifice plate or check
valve/Contact DESMI
Contact DESMI
Dismantle the pump,
remove the cause
Check fuses, cable
connection, and cable
The pump makes noise
1. Cavitation in pump
Suction lift too high/
Suction line wrongly
dimensioned/Liquid
temperature too high
