Xylem LOWARA e-LNE Series, Installation, Operation And Maintenance Manual

Page: 25 / 438

en - Original instructions
25
7.5 The pump unit runs but delivers too
little or no liquid
Cause Remedy
Motor turns in the wrong
direction Check the direction of
rotation and change it if
necessary
Incorrect priming (there are
air bubbles in the suction
pipe or in the pump unit) Repeat the priming
procedure
Cavitation Increase the NPSH
available in the system
Check valve locked in closed
or partially closed position Replace the check
valve
Foot check valve locked in
closed or partially closed
position Replace the foot valve
Flap valve damaged, worn or
faulty (models LNTE and
LNTS) Replace the flap valve
Delivery pipe throttled Remove the throttling
Piping and/or pump unit
clogged Remove the clogging
7.6 The pump unit turns the other way
when turned off
Cause Remedy
Check valve faulty Replace the
check valve
Foot check valve faulty Replace the foot
valve
Flap valve damaged, worn or faulty
(models LNTE and LNTS) Replace the flap
valve
7.7 The pump unit produces excessive
noise and/or vibrations
Cause Remedy
Cavitation Increase the NPSH
available in the system
Unsuitable anchoring to
the ground Check the anchoring to the
ground
Resonance Check the installation
Anti-vibration joints not
installed Install anti-vibration joints on
the suction and delivery
lines of the pump unit
Foreign bodies in the
pump unit Remove the foreign bodies
Motor bearings worn or
faulty Replace the motor bearings
The pump unit does not
turn freely due to a
mechanical fault Send the pump unit to an
authorised workshop for
testing
Motor turns in the wrong Check the direction of
direction rotation and change it if
necessary
7.8 The pump starts up too frequently
(automatic start/stop)
Cause Remedy
Incorrect priming (there are
air bubbles in the suction pipe
or in the pump unit) Repeat the priming
procedure
Check valve locked in closed
or partially closed position Replace the check
valve
Foot check valve locked in
closed or partially closed
position Replace the foot valve
Flap valve damaged, worn or
faulty (models LNTE and
LNTS) Replace the flap valve
Starter (pressure switch,
sensor, etc.) set incorrectly, or
faulty Adjust or replace the
starter
Expansion vessel

no pre-charge, or

undersized, or

not installed

Pre-charge the
expansion vessel,
or

replace the
expansion vessel
with another
suitable one, or

install an expansion
vessel
Pump unit oversized Contact Xylem or the
Authorised Distributor
7.9 The pump unit never stops
(automatic start/stop)
Cause Remedy
The required flow rate is
greater than the one
expected Reduce the required flow
rate
Delivery pipe leaking Eliminate the leaks
Motor turns in the wrong
direction Check the direction of
rotation and change it if
necessary
Pipes, valves or filter
clogged with impurities Remove the impurities
Starter (pressure switch,
sensor, etc.) set incorrectly,
or faulty Adjust or replace the
starter
The pump unit runs but
delivers too little or no
liquid See Par. 7.5