English (GB)
19
14. Maintenance
14.1 Pumps
The internal pump parts are maintenance-free. It is important to
keep the motor clean in order to ensure adequate cooling of the
motor. If the pump is installed in dusty environments, it must be
cleaned and checked regularly. Take the enclosure class of the
motor into account when cleaning.
The motor has maintenance-free, greased-for-life bearings.
14.2 CU 323
The CU 323 is maintenance-free. It must be kept clean and dry.
Protect it against direct sunlight. Furthermore, the CU 323 must
not be outside the ambient temperature range. See section
.
15. Frost protection
Pumps which are not being used during periods of frost should be
drained to avoid damage. Follow the instructions below:
1. Close the isolating valves before and after the pump.
2. Remove the filling and drain plugs.
3. Remember to open the isolating valves and refit the plugs
before the pump is put into operation again.
Do not fit the filling and drain plugs until the pump is to be used
again.
16. Taking out of operation
Switch off the main switch to take the booster system out of
operation.
Individual pumps are taken out of operation by switching off the
corresponding motor-protective circuit breaker, automatic circuit
breaker or fuse.
17. Technical data
17.1 Pressure
Inlet pressure
We recommend that you calculate the inlet pressure in these
cases:
• Water is drawn through long pipes.
• Inlet conditions are poor.
To avoid cavitation, make sure that there is a minimum inlet
pressure on the suction side of the booster system. The minimum
inlet pressure in bar can be calculated as follows:
p
s
> H
v
+
ρ
x g x 10
-5
x NPSH + H
s
- p
b
p
s
= The required minimum inlet pressure in bar read from a
pressure gauge on the suction side of the booster
system.
H
v
= Vapour pressure of the pumped liquid in bar.
ρ
= Density of the pumped liquid in kg/m
3
.
g
= Gravitational acceleration in m/s
2
.
NPSH =
N
et
P
ositive
S
uction
H
ead in metres head.
NPSH can be read from the NPSH curve at the
maximum performance at which the pump will run.
See installation and operating instructions for CM
pumps.
H
s
= Safety margin = minimum 0.1 bar.
p
b
= Barometric pressure in bar. Normal barometric
pressure is 1.013 bar.
Maximum inlet pressure
The actual inlet pressure plus the pressure when the pump is
operating against a closed valve should always be lower than the
maximum system pressure.
Operating pressure
As standard, the maximum operating pressure is 16 bar.
17.2 Temperature
Liquid temperature: 0 to 60 °C.
Ambient temperature: 0 to 40 °C.
17.3 Relative humidity
Maximum 95 %.
17.4 Sound pressure level
For sound pressure level, see installation and operating
instructions for the CM pumps.
The sound pressure level for a number of pumps can be
calculated as follows:
L
max.
= L
pump
+ (n - 1) x 3
L
max.
= Maximum sound pressure level
L
pump
= Sound pressure level for one pump
n
= Number of pumps.
Warning
Before starting work on the pumps, make sure
that the power supply has been switched off.
Lock the main switch with a padlock to ensure
that it cannot be accidentally switched on.
Warning
Ensure that the escaping water does not cause
injury to persons or damage to the motor or other
components.
In hot-water installations, special attention
should be paid to the risk of injury caused by
scalding hot water.
Warning
The conductors in front of the main switch are
still energised. Lock the main switch with a
padlock to ensure that it cannot be accidentally
switched on.
Caution
A positive inlet pressure is required before
startup and during operation.
Note
In this manual, the term "inlet pressure" is
defined as the pressure/vacuum which can be
measured immediately before the booster
system.
Note
Considering the flow in pipes, vibrations, etc.,
the actual sound pressure level of the booster
system will be lower than 90 dB(A).
