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5. Assembly and Installation
– See the rating plate of the pump and the rating plate of the motor
5.1 Installation
Before installing the pump, make sure that all
WARNING!
welding and soldering on the pipe system has
been completed and that the pipe system has been
flushed out if necessary. Dirt will damage the pump.
– Assemble the pump in a dry place free of frost.
– Assemble in a horizontal and flat position. If the pump is positioned
on an incline the bearing will wear more quickly. Vertical operation
only.
– Install the pump in an easily accessible place to facilitate inspection
and disassembly. Always install the pump exactly perpendicular on a
sufficiently heavy concrete base (Fig. 2, 3). Fit a vibration absorber
between the base and the floor.
– Dimensions for installation and connections are given in Paragraph
1.2.1, Table 2 and in Fig. 3.
– For heavy pumps, attach a hook (Fig. 2, 12) or an eye with adequate
load-bearing capacity vertically above the pump (for total weight of
the pump see catalogue or data sheet), so that the pump can be
attached to a crane or other lifting gear for maintenance or repairs.
– Only use the screws provided when fitting an oval flange on the
PN 16 version (MVI 2.../4...) as longer screws could damage the
pump base.
– The arrow on the pump casing indicates the direction of flow.
– Fit the inlet and outlet pipes without stress. Install bellow expansion
joints of restricted length to absorb vibrations. The pipes must be
attached (Fig. 2, 7) in such a way that the pump does not bear the
weight of the pipes.
– Isolation mechanisms (Fig. 2., 2&3) must in principle be installed in
front of and behind the pump to avoid having to empty and refill the
whole installation when inspecting or changing the pump.
– It is advisable to choose an inlet pipe with a nominal width one unit
higher than that of the pump connector.
– To avoid pressure losses, the inlet pipe should be as short as
possible and should not be restricted by bends or valves.
– A backflow preventer (Fig. 2., 4) should be fitted in the outlet pipe.
– The axial face seal should be protected against dry running. An inlet
pressure gauge or level gauge should be installed by the customer.
– If the pump is to be connected directly to the public drinking water
mains, a backflow preventer (Fig. 2., 4) and isolating valve (Fig. 2., 2)
must also be installed in the inlet pipe.
– If the pump is to be connected indirectly via a reservoir, a suction
strainer (Fig. 2, 8) must be provided in the inlet pipe by the customer
to prevent coarse impurities entering the pump.
– With limited nominal pressure PN, ensure that this pressure is produ-
ced from the inlet pressure and the zero flow level:
PN
P
+ P
inlet
Q = 0
– To prevent the formation of air pockets and hence high temperatures
in the upper section of the pump at low flow rates (which would
damage the axial face seal), a bypass pipe can be fitted to the pump
(Fig. 2, BP, accessories).
5.2 Electrical installation
Electrical work must be carried out by a qualified and licen-
sed electrician in strict compliance with local regulations.
– Check that the mains current and voltage comply with the data on
the rating plate.
– Pump/installation must be earthed in compliance with regulations.
– All motors must be fitted with a motor safety switch by the customer
to prevent the motor from overheating.
Adjusting the motor safety switch:
Direct starting current: Adjust to nominal current of the motor in
accordance with the data on the motor rating plate.
Star or triangular circuit starting current: If the motor safety switch is
connected as a star or triangular safety circuit combination at the sup-
ply line it can be adjusted in the same way units operating on direct
starting current. If the motor safety switch is connected to the motor
10
supply line in phase (U1/V1/W1 or U2/V2/W2), then the motor safety
switch should be adjusted to the value of 0.58 of the nominal motor
current.
– The mains cable can be inserted to the left or the right of the termi-
nal box. Open the appropriate hole by removing the moulded cover,
unscrew the PG connector and push the cable through the PG
connector.
– The supply cable must be protected against the effects of heat and
vibrations which may come from the motor or the pump.
– Heat-resistant cable must be used if the pump is fitted in installa-
tions in which the temperature of the fluid pumped exceeds 90 °C.
– Connection to the mains must be carried out in accordance with the
plan of terminal connections for rotary or alternating current in the
terminal box of the pump (Fig. 4).
– The terminal box can be better positioned by rotating the motor
through steps of 90°. To do this, remove the clutch guard (Fig. 1, 2)
and loosen the connecting screws (Fig. 1, 1) of the light and the
motor flange. When assembling the clutch guard, do not forget to
tighten the safety screw.
5.3 Operation with frequency converter
The speed of the pump can be controlled when connected to a
frequency converter. Speed control limits: 40%n
See Installation and Operating Instructions of the frequency converter
for connection and operation.
To avoid overloading the motor coil to the extent that it is damaged
and to avoid increased noise levels, the frequency converter must not
produce speeds due to increased voltage of over 500 V/µs and spikes
of û > 650 V. If such speeds due to increased voltage are possible, an
LC filter (motor filter) should be installed between the frequency con-
verter and the motor. The filter must be designed by the manufacturer
of the frequency converter or filter.
In control devices with frequency converters supplied by WILO, the
filter is already installed.
6. Commissioning
In order to protect the axial face seal, the pump
WARNING!
must not run dry.
– Close both isolating valves and open the vent screw (Fig. 2, 5) by
one and a half or two turns.
– Slowly open the isolating valve (Fig. 2, 2) at the inlet until the air has
escaped from the vent screw and the fluid to be pumped comes
out. The escaping air will be clearly heard hissing.
Tighten the vent screw.
– Slowly open the isolating valve at the outlet (Fig. 2, 3). The manome-
ter installed at the outlet should be checked for any possible pres-
sure instabilities, indicated by a flickering manometer pointer. If the
pressure is unstable, allow more air to escape.
When the temperature of the liquid being pumped is high
and the system is pressurised, any flow escaping from the
vent screw can cause scalding and injuries. The vent
screw should therefore be loosen only slightly.
– When used for the first time, if it is to be used to pump drinking
water the system must be flushed through, so that any dirty water
present will not contaminate the drinking water supply.
– Checking direction of rotation (only for rotary current motors): Check
that the pump rotates in the direction indicated by the arrow on the
pump latern by switching on for a short time. If this is not the case,
interchange 2 phases in the terminal box.
– For pumps with a star or triangular circuit starting current, the
connections of two coils must be interchanged, e.g. U1 with V1 and
U2 with V2.
It is not necessary to check the direction of rotation with AC motors.
– If the fluid temperature is too high, steam may form which may
damage the pump. The pump must therefore not run with the valve
closed for longer than 10 minutes when pumping cold water or for
longer than five minutes when pumping fluid where >60 °C.
We recommend that the flow rate does not drop to below 10 % of
the nominal flow rate so as to avoid a build up of steam in the pump.
n
100%n
.
nom
nom
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