Maintenance / Service - Wilo MVI 10 Notice De Montage Et De Mise En Service

English
NOTE:
The length of the pipe must be at least 2 inches
(50 mm) taller than the venting plug level.
- Close the discharge valve (3), open the suction
valve (2).
- Open the ball valve and the venting plug.
- Unscrew 4 to 5 turns the drain-priming plug (6).
- Fill the pump and the suction pipe completely
until water flows out of the venting plug (5).
- Close the ball valve (which can be left in place),
remove the pipe and close the bleed device (5)
and reseat the drain-priming plug (6).
Dry-running protection
To ensure that the pump is always primed, we rec-
ommend to protect it with a pressure switch or a
float switch.
8.3 Confirm correct rotation
Prior to turning the pump on ensure the rotating
assembly is free of any binding.
WARNING! Electrical shock hazard
Dangers caused by electrical energy must be
excluded.
Do not attempt the following unless 100% sure
power is off.
• Remove either one or both coupling guards.
• Turn the coupling by hand to make sure the pump
turns freely without sticking.
• Once the correct rotation has been confirmed (refer
to three-phase or single-phase procedure noted
below) re-install the coupling guard(s) before the
power is activated full time.
CAUTION! Possible damage of the pump
Prior to starting the pump there must be fluid at
the seal area.
Three-phase motor
• Switch on the motor by briefly pressing the circuit-
breaker and check that it turns in the direction indi-
cated by the arrow located on the lantern or on the
identification label of the pump.
• If the rotation is backwards insure power is off and
switch two of the three motor leads and recheck the
rotation. Once proper rotation is confirmed a amper-
age balance is recommended across each of the
three phases – maximum allowable difference is +/-
5 %.
Single phase motor
• Typically the rotation should be correct on single
phase applications however if the pump seems to
lack performance please check the rotation. If run-
ning backwards refer the motor nameplate for
instructions to reverse rotation.
8
8.4 Starting up
WARNING! Risk of scalding
Under some pump or installation operating condi-
tions (temperature of pumped liquid, volume
flow), the whole pump, including the motor, may
become very hot. There is a real risk of burns just
from touching the pump.
CAUTION! Possible damage of the pump
The pump must not operate at zero flow (closed
discharge valve) for more than 10 minutes with
cold water (T < 104 °F (40 °C)) and more than 5
minutes above 140 °F (60 °C).
We recommend to ensure a minimum flow of
about 10 % of the nominal flow of the pump to
avoid the formation of a vapour lock at the top of
the pump.
• Keep the discharge valve closed.
• Start the pump
• Open venting plug to drain air. If no water leaks
within 20 seconds, close the plug and stop the
pump, then wait 20 seconds to allow air to settle.
• Start again the pump.
• If necessary (particularly if the suction height
exceeds 16 ft - 5 m) repeat these operations.
• If water leaks at draining plug (it means the pump
delivers its pressure), slowly open the discharge
valve. The pump has to be primed.
• Check discharge pressure for pressure fluctuations
with a pressure gauge. If fluctuations are present
please check the inlet conditions and/or re-prime
the pump.
• To insure all air has been removed, close the dis-
charge valve and the draining plug, then stop the
pump 20 seconds, start the pump again and open
the draining plug. Do it as long as air comes out
• Open the discharge valve fully or at a desired posi-
tion determined by the installation.
• Check that the current input does not exceed the
value indicated on the motor data plate.

9 Maintenance / Service

All servicing should be performed by an authorized
service representative!
WARNING! Electrical shock hazard
Dangers caused by electrical energy must be
excluded.
All electrical work must be performed after the
electrical supply has been switched off and
secured against unauthorized switching.
WARNING! Risk of scalding
At high water temperatures and system pressure
close isolating valves before and after the pump.
First, allow pump to cool down.
WILO AG 10/2006