34
6.5
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. Increas-
ing 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 isn’t 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 accurate 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.
6.6
Coping with Dirty Water
Conditions
PS-Pumps
have good resistance to quanti-
ties of sand and fine sediment that can
normally occur in a well. However, any
amount of abrasive material will reduce the
life of this pump, like any other pump.
Extreme sediment can cause the pump to
stick. Sediment can also settle inside the
drop pipe each time the pump stops, and
block the flow. For water sources that contain
high amounts of sand, clay, or other solids,
consider the following suggestions.
To avoid pumping dirty water
1. Have your well purged, developed, or
otherwise improved by a water well contractor
before installing the pump.
2. Temporarily install a more powerful pump
to draw at a high flow rate until the water
looks clean.
3. Set the pump as high as possible in the
well. If the pump can be placed higher than
the perforations in the well casing, it will
probably avoid all but the finest suspended
silt.
4. After lowering the pump in a well, wait at
least 15 minutes for sediment or debris to
settle down.
5. If the water source is at the surface, dig a
shallow well next to the water source to obtain
clean water.
6. If the water source is at the surface, use a
fabric screen to protect the pump (see Section
6.4).
If dirty water cannot be avoided
1. Use a reduced size of drop pipe. This will
maximize the velocity of water flow in order to
exhaust sand particles. Refer to Section 13.2
Water Pipe Sizing Chart. Select the smallest
size pipe that does not impose excessive
friction loss. Use a reducer bushing on the
pump if necessary, to adapt it to a smaller
pipe size (see the caution about plastic
bushings in Section 6.2).
2. Monitor the situation regularly by observing
the volume of water pumped and/or the
current draw of the pump (AC amps – see
Section 9.3 and 13.7). As a pump wears, its
flow rate (and current draw) will decrease
gradually. Replace the pump end when
reduced performance is observed, or before
your season of greatest water demand.
Increased current draw may indicate debris
stuck in the pump and/or pipe.
Question What
effect does hard,
mineralized,
alkaline or salty
water have?
Answer Gener-
ally, none.
Dissolved miner-
als and salts are
not abrasive.
