Installation and Operating Instructions Wilo-Cronoline
19
Englis
h
Troubleshooting guide
10 Troubleshooting guide
Faults
Possible cause
Remedy
Pump does not
start or fails to
run
Pump seized
Switch off power supply, take off pump
head, remove obstruction; if motor
blocked, overhaul/exchange motor/pump
head
Loose terminals
tighten all terminals
Blown fuses/breakers
Check fuses, replace/reset as necessary
Faulty motor
Call service
Tripped overload relay
(excessive amp draw)
throttle hydraulic flow rate down to
nominal on discharge side of pump
Incorrectly set trip relay
(heaters)
Reset thermal overloads to full load
current value specified on name plate
Thermal overload is influenced
by excessive ambient
temperature
Prevent overloads caused by high ambient
temperatures
Tripped PTC relay
Check motor and fan cover for dirt/dust
accumulation and clean if necessary;
Check ambient temperature and if neces-
sary, ensure an ambient temperature
≤
105 °F [40 °C] by forced ventilation.
Pump runs at
reduced capacity
Incorrect rotation
Check direction of rotation, reverse if
necessary
Discharge valve throttled too
far
Slowly open isolating valve
Speed too low
Adjust incorrect terminal bridging
(Y in lieu
∆
)
Air in suction pipe
Check and correct all possible suction
leaks
Pump makes
noise
Insufficient inlet pressure
Raise inlet pressure, ensure minimum
required inlet pressure at suction port,
check and if necessary clean suction-side
isolating valve and strainer
Faulty motor bearings
Arrange for pump to be inspected and, if
necessary, to be repaired by Wilo or other
authorized service.
Impeller rubs on volute
Test the gap between lantern and pump
housing. Clean it, if necessary.
Check that distance from coupling to
lantern is 5 mm
Note:
If you cannot fix the problem, contact service engi-
neer or a Wilo branch office.
