EN
Operating and
maintenance manual
Horizontal multi-stage pump
Serie MH
• with VITON/FKM seals (special versions): from -10°C to +110°C.
If the pump is intended for uses provided for by CEI EN 60335-2-41 the upper
temperature limit, for any combination of materials, is +90°C.
4.2.2 Ambient temperature and altitude
In the case of ambient temperatures higher than +40°C, or the installation of the
pump at an altitude higher than 1,000 metres, the motor must not work at full
capacity to avoid the risk of overheating.
Excessive ambient temperatures and low air density reduce the motor’s capacity to
cool. Below is a non-binding chart of motor capacity percentage based on altitude
or temperature (see Fig. 4).
4.2.3 Maximum number of start-ups
The table shows the maximum number of start-ups per hour for the electric pump.
Power (kW)
Starts for hour
s
e
l
o
p
4
s
e
l
o
p
2
0,37-0,55
0
4
1
0
6
0,75-3
0
4
1
0
6
4-7,5
0
6
0
3
4.2.4 Maximum limit of pressure
The maximum pressure, not to be exceeded, is shown on the data plate (see point
4.3).
4.3 Pump data plate
The data plate, positioned on the side of the
pump’s outer casing, contains the main
information about the machine (Fig. 5).
A) Pump identification code
B) Serial number
C) Date of manufacture
D) Working capacity range
E) Head range
F) Minimum head (as per EN 60335-2-41)
G) Head at 0 capacity
H) Type of motor and functioning
frequency
I) Maximum absorbed power
L) Electrical connections/data of
motor
M) Maximum ambient temperature
N) Motor efficiency class
O) Insulation class of motor,
P) Motor IP rating,
Q) Weight of electric pump
R) Electrical data capacitor (single-phase
motors)
S) Maximum pressure of liquid
T) Maximum operating temperature of
liquid (for uses as per EN 60335-2-41)
4.4 Other plates
For three-phase motors only, a label with arrow on the cover of the motor’s cooling
fan indicates the correct direction of rotation (Fig. 5-F).
A label on the pump as shown in Fig. 5-U indicates:
Tmax 110°C
the pump is suitable for handling liquid at 110°C only for industrial use (uses
other than those covered by CEI EN standard 60335-2-41);
Tmax 90°C
the pump is suitable for handling liquid at 90°C for domestic use (uses
covered by CEI EN standard 60335-2-41);
read the instruction manual carefully before use.
A WRAS label on the pump indicates that the product can be used for
handling drinking water for human use.
5 INSTALLATION AND PREPARATION
For the pump to function correctly and to avoid damage to people or things, some
basic conditions must be observed.
In particular the NPSH and maximum pressure must be checked.
5.1 Checking the NPSH
Check the characteristic curves of the electric pump to evaluate the NPSH factor
(see Fig. 7) and thus avoid cavitation problems in the case of an excessively high gap
between the pump and the level of the liquid to be drawn or due to an excessively
high temperature (Fig. 2).
The maximum height between the pump and the level of liquid “H” can be calculated
using the following formula:
H = pb x 10.2 – NPSH - Hf - Hv – Hs
pb:
Bar pressure or liquid suction pressure [bar].
NPSH: Net positive suction head [m] (Fig. 7)
Hf:
Friction and entrance head losses in the suction piping [m]
Hv:
Steam pressure [m] in relation to the temperature of the liquid (tm) (see Fig.
2-A)
Hs:
Safety margin [m] (minimum 0.5)
If the value calculated is less than “0” the pump should be placed below the liquid
level.
Example
pb = 1 bar
Type of pump: EH 15/4
Capacity: 14 m3/h
NPSH: 1,8 m
Hf = 2,5 m
Temperature of the liquid: +50°C
Hv: 1,3 m
H = pb x 10,2 - NPSH - Hf - Hv - Hs [m].
H = 1 x 10,2 - 1,8 - 2,5 - 1,3 - 0,5 = 4,1 [m]
This means that the maximum height between the pump and the level of the liquid
is 4.1 metres.
5.2 Verifying maximum pressure
Working pressure
It is important to keep the sum of the inlet pressure plus the maximum pressure
of the pump at zero capacity, always lower than the maximum allowed working
pressure (PN). The PN maximum working pressure is shown on the data plate (see
point 4.3).
5.3 Minimum rated capacity
WARNING: The pump must never operate dry (without liquid inside it)
WARNING: The pump must never operate with the discharge valve closed
for more than 5 seconds.
Functioning for a long time at a lower level than the minimum allowed on the data
plate may cause excessive and dangerous overheating of the pump.
For water temperatures over 40°C, the minimum capacity should be increased
according to the temperature of the liquid (see Fig. 3). For liquids other than water
contact the sales and service office.
5.4 Installing the pump
WARNING:
Please observe current accident prevention standards, use
suitable protective devices and refer to the regulations, legislation and local
and/or national laws in the country of installation regarding water and
electricity connection.
WARNING: DO NOT USE THIS PUMP IN ENVIRONMENTS THAT MAY
CONTAIN INFLAMMABLE/EXPLOSIVE OR CHEMICALLY AGGRESSIVE
POWDERS OR GASES.
WARNING: Installing an electric pump may be a rather complex operation.
It should therefore be carried out by skilled and authorised installers.
5.4.1 Assembly
Guidelines
• Install the electric pump in an area that is accessible and protected from frost,
leaving sufficient space around the electric pump to allow for its operation and
maintenance.
• Vertical assembly is not permitted with the motor placed on the lower part (see
Fig.5-V).
• Check that there are no obstacles blocking the air flow to cool the motor, make
sure there is at least 100mm of space in front of the fan (Fig. 5).
• Any liquid leakages or similar occurrences must be drained and must not flood
the place of installation and/or submerge the unit.
• The electric pump must ALWAYS be firmly fixed to a concrete base or to a
metal structure of a size and weight to suit the size and weight of the electric
pump, using screws suitable for the fixing holes provided (see Fig. 6 dimensions,
tightening torques).
• If the pump works with liquid at temperatures above 50 ° C, anchor the pump
only on the side of the motor bracket and leave free the inlet side bracket.
• To reduce vibrations to a minimum, insert vibration-damping seals between the
pump and the base.
• Make sure the pump is correctly orientated (see Fig. 5).
• The connection pipes must be suitable for the operating pressure and the
pumped liquid. Between the connections of the pipes and the pump must be
interposed appropriate sealing gaskets.
• The pipes should be properly supported (Fig. 5-1) and should not rest on the unit.
Do not force the position of the pipes when fixing them to the pump. Flexible
pipes or expansion joints (Fig. 5-2) are necessary to avoid vibrations being
transmitted from the pump to the pipes and vice versa.
• To prevent air bubbles in the suction pipe, give it an inclination of no less than
2%.
• The diameter of the pipe should not be smaller than the diameter of the suction
vent and must be hermetically sealed. If the suction pipe is bigger, install an
eccentric reducer (Fig. 5-6).
• If the pump is above the liquid to be sucked (negative suction head pump) a foot
valve should be fitted to the end of the suction pipe (Fig. 5-3).
• The end of the suction pipe should be sufficiently immersed to prevent air
entering the suction vortex (Fig. 5-7) when the liquid is at minimum level.
• Suitably sized gate valves should be fitted to the suction pipes (Fig. 5-4) and
delivery pipes (Fig. 5-8) to isolate the pump from the circuit in the case of
