Faults, Causes, Remedies - Wilo Initial JET System 4-4-50 Notice De Montage Et De Mise En Service

8. Faults, causes, remedies

DANGER! Switch the system OFF before doing
any work on it!
Faults
Pump does not start
Priming of the pump is difficult
Pump is running but there is no flow
Insufficient pressure within the system
The flow is irregular
Pump vibrates
Unusual motor overheating
Motor trip-out activated
Installation and operating instructions - Wilo-Initial JET system
Causes
No current
Motor trip-out has been activated
The strainer is not immersed
The pump casing is not filled
Air entering through the suction pipe
Foot valve with strainer is not closed
Strainer at the suction side is obstructed Clean the strainer
Suction head too high
The internal units are obstructed by for-
eign bodies
The suction pipe is obstructed
Air entering through the suction piping
No water in the pump
The suction pressure is too low; this is
generally accompanied by cavitation
noises
The motor's supply voltage is too low
The discharge valve is closed
The discharge valve is partially open
High head losses
Suction piping is partially obstructed
The motor fails to run at its nominal
speed (foreign bodies, wrong power
supply, motor's axial alignment is faulty)
The suction head (HA) is too high
The suction pipe has a smaller diameter
than the pump
The strainer and suction piping are par-
tially obstructed
Poorly secured on its frame
Pump is obstructed by foreign bodies
Pump is obstructed by foreign bodies
Wrong power supply
The ambient temperature is too high
The voltage is too low
One phase is interrupted
Remedies
Check the current at the motor terminal
Dismantle and replace the damaged
motor parts
Immerse the strainer (min. 20 cm)
Fill the pump
Check the tightness of suction pipe and
links
Clean the valve
Check suction head (max. 7 m) and
modify the installation
Dismantle the pump and clean it
Clean the entire piping
Check the tightness of the whole pipe up
to the pump and tighten it
Reprime. Check the tightness of the foot
valve
Excessive losses of suction head or sucti-
on head is too large
Check the voltage at the motor terminals
and the sections of the conductors
Check the valve and open it
Open it progressively and completely up
to a stable pressure
Check the head loss
Check the piping and clean it
Dismantle the pump and correct the
problem
Review the installation conditions descri-
bed in this manual
Review the installation conditions descri-
bed in this manual
Remove and clean it
Check the screws of the stud bolts and
tighten them fully
Dismantle the pump and clean it
Dismantle the pump and clean it
Check if the voltage at the connection is
within the normalised tolerances
Ensure air circulation around the unit.
Protect the unit and install it in such a
way that it is not directly exposed to the
sun. The motor is designed to operate at
an ambient temperature of up to + 40 °C.
Check the current using an ammeter or
set to the current indicated at the motor
rating plate
Verify the connections of the power cord
English
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