Wilo COHe, Installation And Operating Instructions Manual

Page: 22 / 28

p. 22 4227862 ed.04
closed
ONE PUMP FAILS TO RUN Thermal relay tripped The pump "fault" indicator on the control box
must be lit.
Check the setting of the thermal relay and
reset it.
Check the direction of rotation, the coupling
or the current requirement of the motor
concerned
Magnetic circuit breaker
defective Check that the motor phases are not in
short-circuit between them. Replace the
motor if necessary.
Reset the circuit breaker.
Pump shaft blocked Switch off the electric supply of the control
box and then check the shaft turns freely, if it
is blocked, dismantle the pump
Winding fault Disconnect the terminal board of the terminal
block and check the stator insulation to
earth. Replace the motor if necessary.
NO DELIVERY PRESSURE Flow higher than booster
capabilities Plan to replace the booster by a more
adequate one (do not forget to contact us in
any case).
One or two pumps are no
more primed Check that the suction strainer does not let
air in or the tank filling point is too close from
the strainer.
Public water pressure lower
than the minimum pressure
planned Contact the public water supply company or
replace the booster. Contact us
A pump is obstructed by
particles Have the pump dismantled and cleaned
Voltage of the motors too
low: Check the voltage on motor terminals
RANDOM OPERATING,
STARTING FREQUENCY
TOO HIGH Pressure transmitter
defective Check the setting: transmitter not stable,
replace it if necessary
Installation capacity too low Add a tank.
No air inside the tank or
under-inflation Pressurize the tank or replace the bladder.
TRIPPING FREQUENCY OF
DRY RUNNING SAFETY
TOO HIGH Setting of dry running
pressure switch too high Set the pressure switch correctly.
Drop of the public water
supply pressure when
starting the pumps Set the dry running pressure switch to the
minimum value. If it recurs, the public water
mains is inadequate; check the pressure
with the pressure gauge when starting the
pumps or contact the public water mains
service.
AUTOMATISM IS NOT
WORKING PROPERLY Control box or cabinet
defective See starting instruction of the control box or
cabinet.
Wires disconnected Check all connections to the terminal block
of the control box.
Transmitter defective Check the contacts, change the transmitter
concerned if necessary