Stairs ST SERIES User manual

Submersible
Deep Well Pump
4”/6’’ ST SERIES
INSTALLATION AND
OPERATING INSTRUCTIONS
These Instructions must be delivered with the pump to the operator.
WARNING: Failure to follow these instructions and comply with all applicable codes
may cause serious bodily injury and/or property damage.

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Installation & Operating Instructions
It is important that all submersible deep well pumps be installed by experienced persons and that all electrical connections
comply with the relevant electrical supply authority requirements.
The electrical connections and checks must be made by a qualified electrician and comply with
applicable local standards.
These instructions are provided for guidance only, and assume a familiarity with submersible pump installation and
commissioning procedures.
Bore Conditions
1. To guard against installing a pump in aggressive or abrasive water, it is suggested that an analysis of the bore water
be submitted to an authorised testing authority prior to installation of the pump. Damage to the pump or motor caused
by abrasive or aggressive water is not covered by the guarantee. The water analysis parameters listed below are
intended as a guide only as various combinations of the below items and others may act as a corrosive fluid:
PH - 6 to 8
Total dissolved solids (PPM) - 1,000 maximum
Chlorides (PPM) - 500 maximum
Fe (PPM) - 2 maximum
C02 (PPM) - 50 maximum
O2 (PPM) - 2 minimum
ST4”Sand content - 150 g/m³maximum
ST6”Sand content - 60 g/m³maximum
WATER QUALITY: The above guide is NOT an indication of safe drinking water. A water analysis for this
purpose should be undertaken.
2. Know the approximate replenishment rate of the bore before selecting a pump. Select a pump with a
maximum of 10% less discharge than the replenishment rate of the bore.
3. Where bores are sunk into aquifers comprising of sand or fine gravel, it is important that they be
adequately screened to prevent the ingress of these materials into the water being pumped. It is also important that
the bore be cleaned prior to the installation of the pump, and that the pumps must not be used for “bailing” or
developing the bore.
4. In the event that the water is entering the bore from a level above the pump (“a cascading bore”), or where the pump is
installed in a large diameter bore, or in a river or other open water sources, a shroud may be required over the pump
to ensure that all water being pumped is drawn over the full length of the motor’s surface. Minimum water velocity past
a motor for adequate cooling should be 0.08m/sec @ 20oC water temperature.

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5. To assist in protecting the integrity and quality of your bore water supply we suggest a bore cap be fitted to the top of
your bore casing at all times. This may also assist pump installation.
Coupling the pump with the motor
NOTE: Before coupling pump to motor ensure pump and motor models are as specified.
For ease of transportation and to minimise potential transport damage, Stairs 4” submersible deep well pumps are
supplied in component form, ie. motor and liquid end boxed separately. For correct coupling, proceed as follows:
- Remove cable guard after removing the lock screws.
- Insert a screwdriver into the shaft end to ensure the pump is free to rotate. Some small resistance is normal.
- Position the pump and motor so that they are aligned along the same axis.
- Insert the motor shaft into the pump coupling, using the screwdriver to rotate the shaft to align the coupling to the
motor shaft.
- On each motor stud fit the four nuts which secure the pump to the motor, tightening them a little at a time in
a diagonal sequence.
- Align the motor cable along the pump, then secure the cable guard with the setscrews into the side of the pump.
CAUTION: BE SURE THE MOTOR KW SIZE IS EQUAL TO (OR EXCEEDS) THE MOTOR KW REQUIRED FOR
THE PUMP.
Ensure the motor voltage & phase matches the supply voltages & phase.
Installation
NOTE: FOR SEALING OF PIPE THREADS ONTO YOUR STAIRS SUBMERSIBLE DEEP WELL PUMP USE
THREAD TAPE ONLY. DO NOT USE PIPE SEALING COMPOUND AT ALL.
1. Drop Pipe
All pipe and fittings must be suited to the maximum pressures available from the pump.
The starting torque of the pump motor tends to give a twist which could cause the pump shell to rub against the inside
walls of the bore casing - especially if rigid PVC or polythene pipe is used. Torque stops can be obtained and installed to
dampen this twisting.
2. Safety Cable
As a precautionary measure, a safety line should be connected to all pumps regardless of the type of drop pipe
used. This line should be fastened to the pump and at the top of the bore casing.
3. Depth of Installation

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For the maximum allowable submergence consult the motor specifications from the motor supplier. Ensure that
the pump is installed at least one (1) metre, preferably 3 metres above the bottom of the bore, and one (1) metre
below the maximum draw down level.
WARNING: If during the initial operation the pump lowers the bore water level down to below the suction inlet it will
be necessary to lower the pump, where feasible or install a level probe protection device to prevent the pump from
running under aerated water conditions.
NOTE: OVER PUMPING OF THE BORE (AERATED WATER) WILL CAUSE DAMAGE TO PUMP
AND OR MOTOR NOT COVERED BY GUARANTEE
Before lowering the pump unit, smooth out any rough spots or sharp edges on the top lip of the
bore casing to prevent damage to the pump or power cables when lowering the unit into the bore.
4. Check Valve
All Stairs submersible deep well pumps are supplied with a check valve, and no additional check valves are
required for open discharge conditions up to a maximum of 80 meters head. For installations greater than 80
meters head, or when used as a pressure system, it is recommended that an additional check valve be fitted
approximately no more than 60 meters vertically above the pump and every 60 meters vertically thereafter. The
fitting of this check valve will limit potential water hammer and consequent pump damage.
5. Pressure System Installation and Pump Controls
Stairs submersible deep well pumps may be used as a pressure system in conjunction with pressure tanks
providing a suitable draw off capacity. When selecting a pressure tank, make sure that the rated tank pressure is
at least 10% greater than the pump pressure at the bore head and the tank draw off capacity is large enough to
limit pump starts to an absolute maximum of those listed on the table below.
While small capacity tanks may be used, extreme care must be taken to ensure the pump unit does not ‘cycle’. It
may be necessary to fit more than one pressure tank to provide the required draw off or to help prevent pump
cycling.
Motor Rating
Average Number of starts per 24hr Day
HP KW
Up to 3/4Up to .55
1 to 51/2 .75 to 4.0
71/2 to 30 5.5 to 22
Single Phase Three Phase
300 300
100 300
50 100
The installation of a ‘drilled check valve’ to the pressure tank may assist in the prevention of pump ‘cycling’ problems.
For further information on these contact your Stairs Dealer.
NOTE: Any automatic switching of the pump giving excessive starts per hour will shorten the life of the pump