Commissioning; Maintenance; Faults, Causes And Remedies - Wilo COE-2 TWI5 Instrucciones De Instalatión Y Funcionamento

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8.4.2 Adjusting the motor protection
Check the current intensity set on the overload
relays (see Fig. 3 - No. 5) according to the rating
plates on the pumps. If necessary, adjust these
values by turning the adjusting knobs.
8.4.3 Float switch with intake from break tank
Set the float switch so that the water is always at
a level of at least about 40 cm above the intake
opening to the system, in order to overcome the
resistance of the foot valve with strainer.
To check the electrical connection, actuate the
float switch by hand to see whether the low-
water display on the switchgear lights up.

8.5 Commissioning

The maximum operating pressure in the system is
given by the pressure of the pumps at zero flow,
with the addition where applicable of the pressure
of the municipal water supply network at the
intake to the pressure boosting system.
Set the main switch on the switchgear to "I" and
the switch on the pumps to "Auto".
Fault
1 NO SUCTION ON ONE OR BOTH
PUMPS.
24
Causes
a) Air being drawn in during suction:
b) The foot valve with strainer on the
break tank is leaking or clogged:
c) High head loss during suction:
d) There is too little or no water pressure
from the municipal network:
e) Suction head in the break tank is too
high:
f) Clogged suction line or closed valve
on the suction line:
g) Incorrect direction of rotation of the
pumps (in the case of the three-phase
version):
Automatic operation of the pressure boosting
system is then performed by the switchgear.
CAUTION! Danger of damage to the pump!
Do not allow the pump to run with the stop valve
on the pressure side closed for more than a few
minutes.

9 Maintenance

• The pressure boosting system does not require
any maintenance during operation.
• The motor bearings are lubricated for their entire
service life.
• The mechanical shaft seal does not require any
maintenance during operation.
• In freezing conditions and for long periods of
pump shutdown, the pump must be drained by
unscrewing the lower plug.
CAUTION! Danger of damage to the pump!
Always fill the pump before using it again.

10 Faults, causes and remedies

Remedy
a) Check for leaks on all connections on
the suction line.
Check that the suction strainer on the
break tank is completely covered by
water.
b) Check for leaks on the foot valve and
replace it if necessary.
c) Calculate the head loss and check
whether it corresponds to the Net
Positive Suction Head of the pumps.
d) If the problem occurs repeatedly, it is
important to use a break tank.
e) Check whether the minimum head of
the break tank corresponds to the Net
Positive Suction Head of the pumps.
f) Check the opening of the valve and if
necessary, clean the pipe.
g) Exchange two connecting cables
(phases) on the motor terminals with
each other.
WILO SE 09/2010