Southern Pump Services Engineering Rainhavester underground tank systems are bespoke systems engineered to suit client’s individual requirements, therefore as one system may not be exactly the same as another the general installation and operating principles are the same.
SPSE Rainhavester Tanks
Rainhavester underground horizontal tanks are available as standard from 1200 litre up to 12000 litres and come complete with calmed inlet system preventing stirring of sediment build up in the bottom of the tank and excessive water level fluctuation (and potential hunting of float level controls), 110mm overflow pipe, access turret (1m high x diameter to suit), raised pump plinth at bottom of tank and pedestrian access cover. Raised pump plinth prevents pump(s) from operating in sediment build up.
Other connections included within tank:
- 110mm or 160mm water inlet spigot connection.
- Mains water top-up connection (typically 110mm unless otherwise indicated).
- Pump discharge connection (typically 1 ¼” BSP unless otherwise indicated).
- For ‘Typical layout drawing of Rainhavester tanks – See Drg RH99-110F’
Submersible Pump(s)
Available in single (duty only) or twin pump arrangement (duty / standby) the SPSE Rainhavester range of stainless pumps are offered for pressure controlled systems, available in 230v or 415v. For general transfer pump applications the SPSE Rainhavester range of grey water pumps are offered.
Technical data sheets for each pump type and size are available.
The SPSE Rainhavester range of pumps incorporate a side inlet connection 1 ¼” BSP female. We recommend the use of SPSE flexible floating inlet assembly comprising hose tail, length of flexible hose (client to cut to length) and floating suction strainer. The use of this type of system is to pump clean water from around the middle of the tank and prevent pumping sediment from the bottom.
Submersible pumps are positioned on pump plinth located in bottom of tank. Pump discharges can be either flexible hose connections or rigid galvanised steel pipework up to top manifold assembly located within access turret of tank. Pipework will consist of non-return valves and fittings to complete.
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Discharge pipework from tank connection NOT included, to be by others
SPSE FS Rainhavester 40 – 65mm range of pumps are freestanding with top discharge connection. They do not require floating suction strainers. This pump range are for water transfer systems to roof tank etc NOT for pressure controlled systems.
Low level cut off Floats
One float (SPSE WA65) require per pump and can be easily wired into pump control box supplied with each pump. Terminals are included for a level control and the ‘link’ needs to be removed and float switch connected.
The float comes in 10m and 20m lengths and needs to be hanging down just above the top of the pump inlet. Fixation of the float can be carried out using cable straps to pump handle or discharge pipework.
Ensure float is secure and cannot come loose as this can result in dry-running of pump unit.
Mains Water Top-Up (Optional)
This system is whereby town mains water can be introduced to partially fill tanks in times of inadequate rainfall i.e Summer periods.
A simple system where mains water is introduced via an ½” or ¾” solenoid valve above ground, allowed to flow into an open pipe (to meet current water bylaw regulations) and controlled via a second float switch (SPSE WA65) within the tank.
A mains water supply pipe is required by the client. The SPSE solenoid valve should be fitted to the mains water pipework and connected to a 230v-1ph-50hz within a junction box. The SPSE WA65 float switch connected on live circuit to open / close the solenoid valve, as required.
The float level control (SPSE WA65) is fixed in the same way as the Low level cut off float.
As a guide only, the mains water top-up float should be set as follows
When the float is hanging down this should be just above the top of the pump. The differential level (switch off level) is purely the client’s choice and not critical, however it is NOT advisable to fill the tank too much with mains water purely from a cost and reduced storage volume of rainwater. The volume of mains water should be enough to meet the supply demand.
Twin Pump Starter Panel (SPSE ER1, ER2)
This type of control panel is used on dual pump pressure controlled or level controlled systems.
Pressure Controlled – Via separate pressure switch, pressure vessel or FC1 pressure control device – System pressure is maintained and controlled using submersible pumps.
Level controlled – Submersible pumps transfer water from underground tank to separate remote tank (normally located on a roof or plantroom). Water level in remote tank is controlled via float level control.
Pressure Controlled System
For this type of system, SPSE can supply, a pressure vessel, pressure switch and gauge free issue for the client to install within system pipework. The pressure kit can be installed anywhere within the pump discharge main (from underground tank) and is simply ‘tee’d’ in the line.
The pressure vessel provides minimal storage and controls the system pressure in conjunction with the pressure switch.
The pump cut in and cut out pressure is dependant on the pump model, pressure vessel size and system requirements.
As a recommendation, cut out pressure 4 bar (60psi); cut in 2.5 bar (38psi).
The pre-charge air pressure of the pressure vessel should be checked prior to filling of water / starting of pumps. Depending on the proposed cut out pressure the pre-charged air pressure of the vessel should be 3-5 psi below the pump cut out pressure.
