English (GB)
17
Using p
min
and Q
max
, the minimum diaphragm tank size, precharge pressure and pressure switch settings
can be found in the guideline table below:
Example
p
min
= 35 m head, Q
max
= 2.5 m
3
/h.
On the basis of this information, the following values can be found in the table:
Minimum diaphragm tank size = 33 litres.
p
pre
= 31.5 m head.
p
cut-in
= 36 m head.
p
cut-out
= 50 m head.
1 m head = 0.098 bar.
8.3 Built-in protection
The motor incorporates an electronic unit which
protects the motor in various situations.
In case of overload, the built-in overload protection
will stop the pump for 5 minutes. After that period,
the pump will attempt to restart.
If the pump has been stopped as a result of dry
running, it will start automatically after 5 minutes.
If the pump is restarted and the borehole is empty,
the pump will stop after 30 seconds.
Resetting of the pump: Switch off the power supply
for 1 minute.
The motor is protected in case of:
•
dry running
•
voltage surges (up to 6000 V)
In areas with high lightning intensity, external
lightning protection is required.
•
overvoltage
•
undervoltage
•
overload
•
overtemperature.
SQE pumps/MSE 3 motors
9. Maintenance and service
The pumps are normally maintenance-free.
Deposits and wear may occur. For that purpose,
service kits and service tools are available from
Grundfos. The Grundfos Service Manual is available
on request.
The pumps can be serviced at a Grundfos service
centre.
9.1 Contaminated pumps
If Grundfos is requested to service the pump,
Grundfos must be contacted with details about the
pumped liquid, etc. before the pump is returned for
service. Otherwise Grundfos can refuse to accept
the pump for service.
However, any application for service (no matter to
whom it may be made) must include details about
the pumped liquid if the pump has been used for
liquids which are injurious to health or toxic.
p
min
[m]
Q
max
[m
3
/h]
p
pre
[m]
p
cut-in
[m]
p
cut-out
[m]
0.6 0.8
1
1.2 1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
8
Diaphragm tank size [litres]
25
8
8
18
18 18 18 24 33 33 50 50 50 50 80 80 80 80 80
22.5
26
40
30
8
8
18
18 18 24 33 33 50 50 50 50 80 80 80 80 80
27
31
45
35
8
18
18
18 18 24 33 33 50 50 50 80 80 80 80 80
31.5
36
50
40
8
18
18
18 18 24 33 50 50 50 80 80 80 80 80
36
41
55
45
8
18
18
18 24 33 33 50 50 50 80 80 80 80
40.5
46
60
50
8
18
18
18 24 33 50 50 50 80 80 80 80
45
51
65
55
18 18
18
18 24 33 50 50 50 80 80 80
49.5
56
70
60
18 18
18
18 24 33 50 50 80 80 80 80
54
61
75
65
18 18
18
24 24 33 50 50 80 80 80 80
58.5
66
80
Note
Via the CU 300 or CU 301, the dry-
running stop limit of the MSE 3 motors
can be adjusted to match the actual
application.
Note
If a pump has been used for a liquid
which is injurious to health or toxic,
the pump will be classified as
contaminated.
