5
2. Place the auto-coupling base unit on the bottom
of the pit. Use a plumb line to establish the cor-
rect positioning. Fasten with heavy-duty expan-
sion bolts. If the bottom of the pit is uneven, the
auto-coupling base unit must be supported so
that it is level when being fastened.
3. Assemble the discharge line in accordance with
the generally accepted procedures and without
exposing the line to distortion or tension.
4. Insert the guide rails in the rings of the auto-cou-
pling base unit and adjust the length of the rails
accurately to the guide rail bracket.
5. Unscrew the provisionally fastened guide rail
bracket, fit it on top of the guide rails and finally
fasten it firmly to the pit wall.
Note: The guide rails must not have any axial play
as this would cause noise during pump operation.
6. Clean out debris from the pit before lowering the
pump into the pit.
7. Fit the auto-coupling half on to the discharge port
of the pump. Then slide the guide bar of this cou-
pling half between the guide rails and lower the
pump into the pit by means of a chain. When the
pump reaches the auto-coupling base unit, the
pump will automatically connect tightly.
8. Hang up the end of the chain on a suitable hook
at the top of the pit.
9. Adjust the length of the motor cable by coiling it
up on a relief fitting, so the cable is not damaged
during operation. Fasten the relief fitting to a suit-
able bracket at the top of the pit. Make sure that
the cables are not sharply bent or pinched.
Note: The end of the cable must not be submerged,
as water may penetrate through the cable into the
motor.
4.2 Free-standing installation
See fig. C, page 54.
AP70 pumps should be provided with a separate
base stand.
For free-standing installation of the pumps, fit a 90°
elbow to the discharge port. The pump can be in-
stalled with a hose or rigid pipe and valves.
In order to facilitate service of the pump, fit a flexible
union or coupling to the discharge line for easy sepa-
ration.
If a hose is used, make sure that the hose does not
buckle and that the inside diameter of the hose
matches that of the discharge port.
If a rigid pipe is used, the union or coupling, non-
return valve and isolating valve should be fitted in
the sequence mentioned, as seen from the pump
side.
Lower the pump into the liquid.
If the pump is installed in muddy conditions or on un-
even ground, it is recommended to support the pump
on bricks.
4.3 Pumps supplied with control box
Pumps supplied with a control box may be supplied
with a level switch with cable. The level switch cable,
if supplied, should be fastened in the retainer on the
pump handle.
The difference in level between start and stop may
be adjusted by adjusting the free length of cable be-
tween the level switch and the retainer.
Large difference in level: Long cable.
Small difference in level: Short cable.
4.4 Separate level controllers
Three-phase AP pumps without control box or level
switch can be supplied with a separate level control-
ler with level switches: Type LC for one-pump instal-
lations and type LCD for two-pump installations.
LC is fitted with two or three level switches. The third
level switch, which is optional, is for high-level alarm.
LCD is fitted with three or four level switches: one for
common stop and two for start of pumps. The fourth
level switch, which is optional, is for high-level alarm.
When installing the level switches, the following
points should be observed:
• To prevent air intake and vibrations, the stop level
switch must be fitted in such a way that the pump
is stopped before the liquid level is lowered below
the top of the pump housing.
• The start level switch should be installed in such
a way that the pump is started at the required
level; however, the pump must always be started
before the liquid level reaches the bottom inlet
pipe in the pit.
• The high-level alarm switch, if installed, should
always be installed about 10 cm above the starting
level switch; however, alarm must always be given
before the liquid level reaches the inlet pipe to the
pit.
5. Electrical connection
The electrical connection of the pump should be car-
ried out in accordance with local regulations.
The operating voltage and frequency are marked on
the nameplate. Voltage tolerance: ±10% of the volt-
age stated on the nameplate. Make sure that the mo-
tor is suitable for the electricity supply available at
the installation site.
5.1 Motor protection
All three-phase GRUNDFOS AP pumps supplied
without control box must be connected to a separate
motor starter. The explosion-proof pumps have a
thermal switch built into the motor windings. The
thermal switch is connected to the control circuit of
the motor starter, see fig. 1.
