Fault Finding Chart - Lowara FHE series Installations- Und Bedienungsanleitungen

8. Fault finding chart

PROBLEM
1. The pump
doesn't start
2. Insufficient or
no delivery
3. The pump vibra-
tes and is too
noisy
4. Overload protec-
tion trips:
– accidentaly
– systematically
PROBABLE CAUSE
A) No electrical power
B) Blown fuses:
B1 Because inadeguate (blowing cur-
rent too low)
B2 Because the motor or the supply
cable are damaged
C) Overload protection previously
tripped
A) The rotating part is partially or complete-
ly obstructed (generally the impeller is
obstructed by foreign objects)
B) The pump is not primed: inadequate filling
or defective suction pipe or foot valve seal
(Warning! The mechanical seal could
have suffered serious damage)
C) Excessive suction lift and/or flow re-
sistance in the suction pipe
D) Wrong direction of rotation
A) The pump is cavitating
B) Motor bearings worn out
C) Foreign objects between the fixed
and rotating parts
A) See 3C
B) Momentary loss of a phase
C) Incorrect setting
D) The pump's delivery is higher than the
rated one
E) Dense and viscous liquid
POSSIBLE REMEDIES
A) Supply electrical power
B1 Replace fuses with adequate ones
B2 Repair the motor or replace the cable
C)Reset the protection (if it trips again
see problem 4)
A) Dismantle the pump and clean it
B) Fill the pump with liquid after having
checked the seal of the suction pipe
and foot valve. Also check the in-
tegrity of the mechanical seal
C) - Reduce the suction lift.
- Use a larger diameter pipe.
- Flush the foot valve.
- Replace the foot valve with a big-
ger one
D) Switch two leads in the terminal
board or starter
A) - Choke the delivery
- See 2C
B) Replace the bearings
C) See 2A
C) Set to rated current
D) Close the delivery valve until the ca-
pacity returns to the rated value
E) Determine the actual power require-
ments and replace the motor ac-
cordingly
en
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