3.1. Suction pipe
If the suction pipe is longer than 10 m, use an
internal pipe diameter larger than the pump
suction connection.
The suction pipe must be perfectly airtight and be
led upwards in order to avoid air pockets.
With a
pump located above the water level
(suction lift operation, fig. 1A) fit a foot valve with
strainer which must always remain immersed.
With the
liquid level on the suction side above
the pump
(inflow under positive suction head,
fig. 1B) fit an inlet gate valve.
For suction from a storage tank fit an anti-backflow
valve.
Follow local specifications if increasing network
pressure.
Install a strainer on the suction side of the
pump to prevent foreign particles from
entering the pump.
3.2. Delivery pipe
Fit a gate valve in the delivery pipe to adjust
delivery, head and absorbed power.
Install a pressure gauge between the pump and
the gate valve.
ATTENTION:
install a check valve between the
pump and the gate valve in order to avoid rever-
se flow after switching off the pump unit and to
protect the pump from water hammers.
With servooperated shut-off devices, provide an
air vessel or another protection device against
surge of pressure in the case of sudden changes
of flow rate.
4. Electrical connection
Electrical connection must be carried
out only by a qualified electrician in
accordance with local regulations.
Follow all safety standards.
The unit must be properly earthed (grounded).
Make sure the frequency and mains voltage
correspond with the name plate data.
The motors with supply cur-
rent directly switched by ther-
mally sensitive switches can
start automatically.
Install a
device for disconnection from the
mains
(switch) with a contact separation of at
least 3 mm on all poles.
4.1. Single-phase pumps MXSUM
Supplied with incor-
porated thermal pro-
tector.
The motor will stop
if overheating is de-
tected. When the win-
dings cool down (af-
ter 2 to 4 minutes),
the thermal protector
enables re-starting.
Control box with ca-
pacitor supplied on
request.
Electrical diagram
4.2. Three-phase pumps MXSU
Install in the control box an overload-protective
device in accordance with the name-plate current.
5. Starting
ATTENTION: never run the pump dry - not
even for a short trial run.
Start the pump after filling it completely with liquid.
When the pump is located above the water
level
(suction lift operation, fig. 1A) or with a
positive suction head which is too low (less than
1 m) to open the non-return valve, fill the suction
pipe and the pump through the priming hole
(ref. 6, fig. 1).
6
Fig. 2 Pump supported by the pipes
4.93.177.1
4.93.002/1
M
1
maroon
green/yellow
black
grey
