Free-Standing Installation; Adjustment Of The Float Switch Cable Length - Grundfos UNILIFT APG Installation And Operating Instructions Manual

5.5 Free-standing installation

See the appendix for dimensional drawing.
For free-standing installation of the pumps, fit a 90°
elbow to the outlet. The pump can be installed with a
rigid pipe and valves.
In order to facilitate service of the pump, fit a flexible
connection or coupling to the outlet pipe for easy
separation.
If a rigid pipe is used, the union or coupling, non-
return valve and isolating valve must be fitted in the
sequence mentioned, as seen from the pump side.
A flexible element in the tubing is also needed in
order to separate the pipe vibration and sound from
the system.
If the pump is installed in muddy conditions or on
uneven ground, we recommend that you support the
pump on some solid platforms.
5.6 Adjustment of the float switch cable
length
For pumps with a float switch, the difference in level
between start and stop can be adjusted by changing
the free cable length between the float switch and the
pump handle.
• An increased free cable length will result in fewer
starts and stops and a large difference in level.
• A reduced free cable length will result in more
frequent starts and stops and a small difference in
level.
The stop level must be above the pump inlet to
prevent the pump from taking in air.
The start level must be below the liquid in-
let of the pit to avoid backflow into the sys-
tem.
Start and stop levels
3
2
1
Pos. Description
1 Stop
2 Start
3 Cable length (L)
The start and stop levels vary according to the cable
length.
Cable length (L) Start
[mm] [mm]
100 (minimum
560
length)
260 (maximum
580
length)
Intermittent operation
During intermittent operation, the motor must
always have a minimum liquid level of 250 mm from
the bottom.
Continuous operation
During continuous operation, the motor and the pump
inlet must always have a minimum liquid level of 360
mm from the bottom.
Related information
4.1.1 Minimum space
5.3 Positioning of the product
9.4 The pump runs but gives no water
Stop
[mm]
360
250 (only intermit-
tent operation)
11