English (GB)
7
10.1 Limitations to operation
The flow limits stated in the table below apply to the optimum
operating ranges of the modules as regards efficiency.
The pressure limits stated in the table below must be observed.
1) Contact Grundfos if higher pressures are required.
2)
Note:
If the maximum inlet/outlet pressure is exceeded, install
a safety valve.
10.1.1 Cooling
The temperature and flow limits stated in the table below must be
observed to ensure sufficient cooling of the motor.
10.1.2 Flushing of the booster module
When a module is flushed, the flow must be reduced to maximum
10 % of the rated flow at a minimum pressure of 2 bar. The
modules must be stopped while the system is flushed. See
section
.
The flushing procedure depends on the operating condition:
•
Intermittent operation
If the booster module has to be stopped for more than 30
minutes, it must be flushed through with clean freshwater for
approx. 10 minutes. The flushing must be continued until the
module is completely filled with clean freshwater. The salinity
of the flush water must be below 500 ppm on the discharge
side.
• Continuous
•
operation
BM:
Once every 24 hours, the module should be stopped and
flushed through with the pumped liquid by means of the feed
pump.
BMhp:
Due to an internal bypass, it is not necessary to stop
the BMhp booster modules every 24 hours.
• Interruption of operation
In case of power, pump or motor failure, the booster module
must be cooled and flushed through with clean freshwater.
The drain plug can be used when flushing the booster module.
The booster module can also be disconnected, removed,
dismantled and cleaned with clean freshwater.
10.1.3 Frequency of starts and stops
Minimum 1 per year is recommended.
Maximum 20 per hour.
Maximum 100 per day.
11. Automatic monitoring devices
To protect the modules against dry running and to ensure a
minimum flow of cooling water past the motors, the system must
be fitted with flow and pressure monitoring devices (figures
to
).
The pressure switch on the suction side is set in accordance with
the estimated inlet pressure. At a pressure lower than 0.5 bar for
BM 4" and BM/BMhp 6", and 1 bar for BM/BMhp 8", an alarm is
given and the module must be stopped without delay.
All discharge connections to the system should be fitted with a
flow switch which will stop the system at the set minimum flows.
The above monitoring devices ensure a correct inlet pressure and
a minimum flow of cooling water past the motor.
If the modules are stopped automatically, automatic flushing is
recommended. See section
10.1.2 Flushing of the booster
.
12. Checking of operation
Depending on the number of operating hours of the modules, the
following should be checked at suitable intervals:
• flow
• starting frequency
• control and protective devices
• liquid temperature
• minimum flow through modules during operation.
If any of the above checks reveal any abnormal operating details,
inspection should be carried out in accordance with section
We recommend to use the log book at the end of these
instructions.
Recommended flow rate at 25 °C / 77 °F
Type
m
3
/h
US gpm
50 Hz
60 Hz
50 Hz
60 Hz
BM 3A
0.8 - 4.4
1.0 - 4.7
3.5 - 20
4.4 - 21
BM 5A
2.5 - 6.8
3.0 - 7.7
11-30
13-34
BM 9
4.0 - 11
4.8 - 11
17-48
21-48
BM/BMhp 17
8-22
10-26
35-176
44-115
BM/BMhp 30
15-38
19-45
66-167
84-198
BM/BMhp 46
24-60
28-72
106-264
123-317
BM/BMhp 60
30-75
37-90
132-330
163-396
BM/BMhp 77
38-96
47-120
167-422
207-528
BM/BMhp 95
47-118
57-143
207-520
251-629
BM/BMhp 125
62-156
75-187
273-686
330-823
BM/BMhp 160
78-195
90-215
343-858
396-946
BM/BMhp 215
98-265
115-310
431-1166
506-1364
Recommended pressure
1)
Type
Inlet pressure
Outlet pressure
Min.
Max.
2)
Max.
2)
[bar]
[psi]
[bar]
[psi]
[bar]
[psi]
BM 4"
0.5
7.25
60
870
80
1160
BM 6"
0.5
7.25
50
725
80
1160
BM 8"
1
14.5
25
362
70
1015
BMhp 6"
0.5
7.25
80
725
80
1160
BMhp 8"
1
14.5
80
362
80
1015
Maximum permissible liquid temperature
Motor
Maximum
liquid
temperature
Minimum
flow velocity
past the
motor
Minimum flow
[°C]
[°F]
[m/s (ft/s)]
[m
3
/h (US GPM)]
Grundfos 4"
40
104
≥
0.15 (0.49)
≥
0.8 (3.5)
Grundfos 6"
40
104
≥
0.15 (0.49)
≥
5.5 (24)
Grundfos 8"
40
104
≥
0.15 (0.49)
≥
18.5 (81.5)
Note
When pumping water with a salinity above 2000 ppm
NaCl, the module must be flushed through in the flow
direction as described in the following.
Caution
8" modules: Maximum 20 per day.
