DAB CM-G, Instruction For Installation And Maintenance

Page: 18 / 92

ENGLISH
13

The pump may be fitted either on the delivery or on
the return pipe, with the motor axis in horizontal or
vertical position, as long as the terminal board box is
never facing downwards
(Fig.C) so as to avoid
dangerous water infiltrations in the case of leaks.

It is possible to install the pump with the standard
brackets (fig. 8)

To facilitate checking and replacement operations,
install the pump in a position with easy access.

The arrows on the pump body indicate the direction
of flow. It is recommended to use interception gate
valves on the intake and delivery pipes, to prevent
drainage of the system when it is to be repaired. Fit
also a by-pass circuit between delivery and intake to
guarantee minimum recycling if electrovalves are
used in the pipes, so as to avoid the creation of
dangerous temperature rises.

Ensure that the plant is provided with an air bleeding
system and that the expansion chamber (if provided)
is installed before the intake aperture. If the pump is
installed on the delivery of an open vessel circuit,
ensure that the safety pipe is connected before the
pump.

When fitting the pump on the system, ensure that
the metal pipes do not weigh down on the pump
body, transmitting excess forces or stress that could
cause cracks or breakages.

To avoid transmitting noise and vibrations, fit
vibration-damping couplings on the intake and
delivery apertures.
9. ELECTRICAL CONNECTION
Caution! Always follow the safety regulations!
Scrupulously follow the wiring
diagrams inside the terminal
board box and those on page 77 of
this manual.

The electrical connections must be made
exclusively by skilled personnel as required by
the safety regulations in force.
The requirements of the electric energy supply
company must be scrupulously complied with.
In
the case of three-phase motors with star-delta start,
ensure that the switch-over time from star to delta is
as short as possible and that it falls within
table B on page 76.

Before opening the terminal board and working on
the pump, ensure that the power has been
switched off.

Check the mains voltage before making any
connection. If it is the same as the voltage on the
data plate, proceed to connect the wires to the
terminal board,
giving priority to the earth lead.
(Fig. D).

ENSURE THAT THE EARTH SYSTEM IS
EFFICIENT AND THAT THERE IS THE
POSSIBILITY OF MAKING A GOOD
CONNECTION!

The pumps must always be connected to an external
switch.

Single-phase motors are provided with thermal
overload protection and may be connected directly to
the mains.

Three-phase motors must be protected with special
remote-control motor-protectors calibrated for the
current shown on the plate.

In systems where twin pumps are fitted, provide
separate wiring and switches for each pump so as to
ensure continuous service.
10. STARTING UP
As well as being at high temperature
and high pressure, the fluid in the
system may also be in the form of
steam!
DANGER OF BURNING!
It may be dangerous even to touch
the pump or parts of the system.
Before starting up you must fill the system with water and
bleed the air. Bleed the residual air from the pump body
through the bleeding cock provided until only water comes
out
(Fig. E) . This ensures that the mechanical seal is well
lubricated and that the pump immediately starts to work
regularly.
Dry operation, even for brief periods, causes
irreparable damage to the mechanical seal.

Switch on the power and, on three-phase versions,
check that the motor is turning in the right direction, that
is clockwise when viewed from the fan side,
(Fig. F) .
Otherwise invert any two phase leads, after having
disconnected the pump from the mains.

With the pump running, check the supply voltage at the
motor terminals, which must not differ from the rated
value by +/- 5%
(Fig. G) .

With the unit at regular running speed, check that the
current absorbed by the motor does not exceed the
value on the data plate.
11. PRECAUTIONS

The electropump should not be started an excessive
number of times in one hour. The maximum admissible
value is as follows:
Maximum number
of start per hour
Single-Phase Motors 30
Three-Phase Mot. up to 5.5 HP 20 ÷ 30
Three-Phase Mot. from 7.5 to 60 HP 5 ÷ 10
11.1 Danger of frost
When the pump remains inactive for a long time at
temperatures of less than 0°C, the pump body must be
completely emptied to prevent possible cracking of the
hydraulic components. This operation is advisable even in
the event of prolonged inactivity at normal temperature.