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BERNT LORENTZ GmbH & Co. KG Kroegerskoppel 7, 24558 Henstedt-Ulzburg, Germany, Tel. +49 (0) 4193 7548 - 0, Fax - 29, www.lorentz.de
Errors excepted and possible alterations without prior notice.
5.5 Installation in a Surface Water Source
This refers to a surface well, spring, pond, lake,
river or tank.
Positioning the pump The pump may be placed in an
inclined position with a min. angle of 30° if desired.
head of water starting at the SURFACE of the water in
the source. Increasing the submergence of the pump
(placing it lower in the source) will NOT cause it to work
harder or to pump less water. Avoid placing the pump
close to the bottom where it will pick up sediment.
Filtration at the pump intake PS pumps will tolerate
small amounts of sand, but you may need to filter out
larger debris that is normally found in a pond or stream.
You can construct a simple coarse screen to protect
the pump and to reduce the nuisance of debris in your
water system. One method is to wrap the pump with
about 6-8 layers of loosely-woven fabric or screen, of
a material that will not decay or rust. Some sugges-
tions are fiberglass window screen, agricultural shade
cloth, or weed-barrier fabric (available from nursery and
landscaping suppliers). Bind the fabric or screen with
all-stainless hose clamps, rubber, or polypropylene rope.
Do not use nylon; it softens with submersion in water.
An improved method is to construct a sealed pump
enclosure from 4-6 in plastic pipe, with many holes or
slots to let water in. Then, wrap the screen around that
enclosure. This will distribute the flow through a much
larger area of screen. After cutting holes or slots in the
plastic pipe, wipe the inside carefully to remove plastic
shavings and dust.
WARNING for SIPHON APPLICA-
TIONS If a pump system has a
vertical lift of less than 33 ft (10 m)
up from the surface of the water
source, and then the water flows downhill to a
lower point, a siphon effect may cause suction
at the pump outlet. This will cause an upward
thrust on the motor shaft, resulting in damage
to the motor. Prevent this by installing an air
vent or a vacuum breaker at the high point on
the pipe.
CAUTION The pump must be fully
submerged. A helical rotor pump
may overheat and stop (temporar-
ily) if the pump end is not fully
submerged.
CAUTION High water temperature
can cause failure to start. Low
temperature can reduce lift and
flow capacity. This can occur in
surface water during weather extremes, due to
temporary expansion or contraction of the
rubber stator. The product specifications say:
Optimum water temp. is 46°F to 72°F (8°C to
22°C). Other ranges are available by special
order. These performance problems are
temporary and will NOT damage the pump. If
you are uncertain about using the pump you
received, contact your supplier before installa-
tion.
5.6 Deep Well Setting — How Deep?
PS pumps may be submersed as deep as necessary to
ensure reliable water supply. The lift load on the pump
is determined by the vertical head of water starting at
the SURFACE of the water in the source. Increasing the
submergence of the pump (placing it lower in the well)
will NOT cause it to work harder or to pump less water,
nor will it increase the stress or wear on the pump.
There are reasons NOT to set the pump near the bottom
of the well, if it is not necessary:
1. A deep setting will increase the size requirements,
costs and weight of pipe and cable.
2. A deep setting may increase the chance of sand or
sediment being drawn into the pump.
To make an informed decision, it is helpful to have ac-
curate data for your water source. In most places, drillers
are required to report the details and the performance
of wells that they drill. If you do not have the driller’s
well record, you may be able to obtain a copy from your
regional government office that oversees ground water
resources and issues drilling permits. In USA, it is a state
office, typically called Department of Natural Resources
or State Engineer’s Office. However, the data may be
missing or inaccurate, and conditions can change over
the years. In critical cases, it is wise to have the well
re-tested by a water well contractor.
Models 03, 03H, 04 and 04H have a small “vent hole”
near the top of the pump (photo). If the hole is not
submersed, it will suck air and prevent the pump from
performing fully. The purpose of this hole is to allow
water to fill an internal gap, to conduct heat away from
the rubber stator.
River or stream To reduce the intake of sediment,
do not place the intake very close to the bottom of the
stream or pond. Secure the pump from logs and debris
that may float downstream. Use stainless steel wire rope
or chain instead of plastic safety rope (plastic rope will
weaken in sunlight). Consider digging a shallow well
near the stream. This will allow filtration of the water
through the earth, and will protect the pump from float-
ing debris or human tampering.
CAUTION The low-water probe
must be positioned vertically,
within 10°. Normally, it is to be
installed on the pipe above the
pump outlet, as shown in section 4.10. This will
only work if the pump is installed vertically. If
the pump is will NOT be vertical, find an
alternative way to mount or suspend the probe,
so that it is higher than the pump, and in a
vertical position.
Is a flow sleeve required? NO, not within the normal
temperature range. The PS pumps high-efficiency motor
generates very little heat. A conventional submersible
pump requires a flow sleeve to assist motor cooling
when installed in open water (not confined by a narrow
casing). It is a piece of 4-6 in pipe that surrounds the
pump to increase flow around the motor.
Depth of submersion PS pumps may be submersed
as deep as necessary to ensure reliable water supply.
The lift load on the pump is determined by the vertical
min. 30°
Figure 22: Minimum angle when positioning the
pump in an inclined position
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