Grundfos SE - Inspecting and Adjusting Impeller Clearance

Drain the leakage chamber of the pump
after 2000 operating hours.
WARNING
Pressurised system
Death or serious personal injury
‐ The oil chamber may be under
pressure. Loosen the screws carefully
and do not remove them until the
pressure has been fully relieved.
There must be minimum 10 % air in the
seal housing due to thermal expansion of
the motor liquid during operation.
8.2 Inspecting and adjusting the impeller
clearance
For pumps with the closed S-tube
®
impeller, the
impeller clearance is the distance between the bottom
of the impeller and stationary wear ring.
For pumps fitted with the open S-tube
®
, the impeller
clearance is the distance between the bottom of the
impeller and the suction cover.
The correct impeller clearance is required to maintain
the pump's hydraulic performance and to prevent
clogging.
Check the impeller clearance every time
service is carried out to prevent hot
surfaces in the hydraulic parts.
Clearance sizes for closed S-tube
®
impellers
Pressure range
Impeller clearance
[mm]
Turning angle of set
screw [degrees]
E = Extra-low pressure single-channel S-tube
®
0.9 ± 0.1 170 °
E = Extra-low pressure two-channel S-tube
®
0.7 ± 0.1 140 °
L = Low-pressure single-channel S-tube
®
0.9 ± 0.1 170 °
L = Low-pressure two-channel S-tube
®
0.7 ± 0.1 140 °
M = Medium pressure 0.6 ± 0.1 125 °
H = High pressure 0.6 ± 0.1 125 °
S = Super-high pressure 0.5 ± 0.1 110 °
Clearance sizes for open S-tube
®
impellers
Pressure range
Impeller clearance
[mm]
Turning Angle of Set
Screw (degrees)
H = High pressure 0.5 ± 0.1 110 °
S = Super-high pressure 0.5 ± 0.1 110 °
DANGER
Electric shock
Death or serious personal injury
‐ Before starting any work on the
product, make sure that the power
supply is switched off and that it cannot
be switched on unintentionally.
The impeller clearance of installation types
S and C can be inspected directly through
the pump inlet.
The impeller clearance of installation types
D and H can be inspected and adjusted
with the pump installed on the base stand
and connected to the pipes.
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English (GB)