Grundfos S2 Série Mode D'emploi page 27

10.4.2 Dry-installed pumps, installation types D and H
Check and adjust the impeller clearance with the pump installed on
the pump stand and connected to the pipes.
In these pumps, the inlet cover is located between the pump
housing and the outer connection flange at the inlet side of the
pump.
Depending on the construction, there are two methods to set the
impeller clearance.
Method 1
Pump types
Ranges 72 and 74
S2.35.xxx.xxxx.x.xxx.
S2.40.xxx.xxxx.x.xxx.
S3.50.A240.xxxx.x.xxx.
Range 78
S3.45.xxx.xxxx.x.xxx.
S3.50.xxx.xxxx.x.xxx.
S3.55.xxx.xxxx.x.xxx.
S4.50.xxx.xxxx.x.xxx.
S = 1.3 ± 0.2
L
12a
35
12c
50
A-A
Impeller clearance, installation types D and H, method 1
These pump types have threaded holes for the fastening screws
(35) of the inlet cover (12a) in the pump housing (50) as shown in
fig. Impeller clearance, installation types D and H, method 1. Set
the impeller clearance as follows:
1. Loosen the three set screws (12c) and close the impeller
clearance "S" by tightening the six fastening screws (35)
diagonally to move the inlet cover evenly.
Do not use excessive force when tightening the
fastening screws as this may damage the bearings.
The movement is usually 0.04 to 0.12 in (1 to 3 mm.)
2. Measure the distance "L" between the inlet cover and the pump
housing at three points next to the set screws. Use feeler
gauges or callipers and make a note of the distance.
3. Loosen the fastening screws and draw back the inlet cover by
0.051 in ± 0.0079 (1.3 mm ± 0.2 mm). Use the three set screws
(approximately one 150 ° turn with an 1 1/8" (M27) set screw)
and the distance "L" as a reference.
4. Tighten all fastening screws and check that the distance "L" at
the three reference points is stable at the new value.
A-A
Method 2
Pump types
Range 72 and 74
S3.45.xxx.xxxx.x.xxx.
S3.50.xxx.xxxx.x.xxx.
S3.55.A20.xxxx.x.xxx.
S = 1.3 ± 0.2
L
12a
35
12c
12
50
A-A
Impeller clearance, installation type D and H, method 2
These pump types have threaded holes in the inlet cover (12a) for
the fastening screws (35) as shown in fig. Impeller clearance,
installation type D and H, method 2. Set the impeller clearance as
follows:
1. Loosen the six fastening screws (35) and close the impeller
clearance "S" by tightening the three set screws (12c). Tighten
the screws diagonally to move the inlet cover evenly.
Do not use excessive force when tightening the
fastening screws as this may damage the bearings.
The movement is usually 0.04 to 0.12 (1 to 3 mm.)
2. Measure the distance "L" between the inlet cover and the pump
housing at three points next to the set screws. Use feeler
gauges or callipers and make a note of the distance.
3. Loosen the set screws and draw back the inlet cover by 0.051 in
± 0.0079 (1.3 mm ± 0.2 mm). Use the six fastening screws
(approximately one 270 ° turn of an 1/2" (M12) fastening screw)
and the distance "L" as a reference.
4. Tighten all set screws and check that the distance "L" at the
three reference points is stable at the new value.
A-A
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