Grundfos SP Installation And Operating Instructions Manual page 13

6.6.2 If a steel riser pipe is used
We recommend that you always use steel riser
pipes with the large submersible pumps. Use an
approved pipe thread compound on all joints.
Make sure the joints are adequately tightened in
order to prevent the joints from coming loose
when the motor starts and stops.
When tightened, make sure that the first section
of the riser pipe does not come in contact with
the check valve retainer.
After the first section of the riser pipe has been
attached to the pump, clamp the lifting wire to
the pump, if there is a provision on the pump for
a lifting wire. If not, clamp the lifting wire to the
first section of the riser pipe.
When raising the pump and riser pipe section to
upright position, be careful not to place bending
stress on the pump by picking it up by the pump
end only.
Make sure that the power cables are not cut or
damaged in any way when the pump is being
lowered in the well.
Fasten the submersible drop cable to the riser
pipe at frequent intervals to prevent sagging,
looping or possible cable damage. Nylon cable
clips or waterproof tape may be used. Protect
the cable splice by securing it with clips or tape
just above and below the splice.
6.6.3 If a plastic or flexible riser pipe is used
We recommend that you use plastic type riser
pipes only with the smaller domestic
submersible pumps.
CAUTION
When a plastic riser pipe is used, we
Caution
recommend that you attach a safety
cable to the pump to lower and raise
it.
Important: Plastic and flexible pipes
tend to stretch under load. Take this
stretching into account when securing
the cable to the riser pipe. Leave 3 to
4 inches of slack between clips or
taped points to allow for this
stretching. This tendency for plastic
and flexible pipe to stretch also
affects the calculation of the pump
Note
installation depth. As a general rule,
you can estimate that plastic pipe
stretches to approximately 2 % of its
length. For example, if you installed
200 feet (61 m) of plastic riser pipe,
the pump may actually be down 204
feet (62 m). If the installation depth is
critical, check with the manufacturer
of the pipe to determine how to
compensate for pipe stretch.
Contact the pipe manufacturer or representative
to ensure that the pipe type and physical
characteristics are suitable for this use.
Use the correct joint compound recommended
by the pipe manufacturer. In addition to making
sure that joints are securely fastened, we
recommend that you use a torque arrester when
using a plastic pipe.
Do not connect the first plastic or flexible riser
pipe section directly to the pump. Always attach
a metallic nipple or adapter into the valve casing
at the top of the pump. When tightened, make
sure that the threaded end of the nipple or
adapter does not come in contact with the check
valve retainer.
Fasten the submersible drop cable to the riser
pipe at frequent intervals to prevent sagging,
looping and possible cable damage. Grundfos
nylon cable clips or waterproof tape may be
used. Protect the cable splice by securing it with
Grundfos cable clips or tape just above each
joint.
Check valves
Always install a check valve at the top of the
well. In addition, for installations deeper than
200 feet (61 m), install check valves at no more
than 200 ft (61 m) intervals.
Protect the well from contamination
To protect against surface water entering the
well and contaminating the water source, make
sure that the well is finished off above grade and
that a locally approved well seal or pitless
adapter unit is utilized.
13