Problems, Causes And Solutions - Wilo Sub TWU 6 Instrucciones De Instalación Y Funcionamiento

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8 Problems, Causes and Solutions

Problems
Pump does not run
No or insufficient capacity a) Voltage too low
Pump switches on too
frequently
If the fault cannot be remedied, please contact WILO customer services.
12
Causes
a) Incorrect voltage or voltage drop.
b) Break in connecting cable
c) Motor overload control triggered
b) Suction filter blocked
c) Incorrect motor direction of rotation
d) Low-water protection or water level in well
too low
a) Insufficient switching difference between
on/off pressure in pressure switch/gauge
b) Incorrect arrangement of dipped electro-
des.
c) Storage volume of diaphragm pressure
vessel too small or prepressure setting too
low
Solutions
a) Check applied voltage during start-up; inade-
quate cable cross-sections can lead to a drop in
voltage which prevents the motor from running
normally.
b) Measure resistance between phases. If neces-
sary, the pump must be raised and the cable
checked.
c) Check current values at the thermal trip device
and compare with the rating plate data.
Important: In the event of repeated triggering do not
simply keep switching back on; determine the cause.
Continuously switching back on can quickly lead to
motor damage (through overheating) (witihn one mi-
nute).
a) Check electrical power supply at switchgear.
b) Lift pump out of bore-hole, clean suction filter.
c) Swap any two phases in the switchgear.
d) Check water level in bore-hole/well; it must be at
least 0.2 m above the pump pressure-pipe con-
nection.
a) Increase difference between on and off points
b) Increase gaps between dipped electrodes and
thus regulate switching times.
c) – Check switching pressure settings and reset
– Check vessel prepressure (no water in vessel)
– Provide additional pressure vessel or install
tank with greater nominal volume.
Subject to technical alterations!