Handy Pump Information

Single Phase Single-phase electricity is what you have in your house. You generally talk about household electrical service as single-phase, 240-volt AC service.
Three Phase Three-phase electric power is common in a lot of industrial buildings as it is used to power large motors and other heavy loads. It is a common method of alternating-current electric power generation, transmission and distribution.
Negative Head negative head system exists when there is insufficient pressure or head of water under gravity to provide a flow / pressure at the outlet. Typically a negative head condition exists where the flow from the outlet is less than 1 litre/min.
Positive Head positive head system exists when sufficient pressure is available under gravity to provide a flow at the outlet. Typically a positive head condition exists where the flow from the outlet is more than 1 litre/min.
Flow Rate The amount of fluid that flows in a given time
Pressures Pumps are rated in ‘bar’ which is the measure of pressure, 1 bar pressure being equal to 10 metres static head of water.
Automatic Flow Switch Designed to provide a constant water supply from a break tank, these units rely on gravity flow to activate. Features include fully automatic control with dry run protection.
Header Tank A raised tank of water maintaining pressure in a plumbing system.
Break Tank Break tanks are implemented in boosting systems in order to supply the system if the mains supply becomes insufficient.
Pressure Vessel pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.
Expansion Vessel An expansion tank or expansion vessel is a small tank used to protect closed (not open to atmospheric pressure) water heating systems and domestic hot water systems from excessive pressure. The tank is partially filled with air, whose compressibility cushions shock caused by water hammer and absorbs excess water pressure caused by thermal expansion.
Potable drinking quality water. Potable vessel will mean suitable for storing drinking quality water.
Centrifugal moving or directed outward from the centre. A pump that uses an impeller with backward-swept arms to push water or other fluids outwards from the centre of the axis. The efficiency tends to increase with flow rate up to a point midway through the operating range (peak efficiency) and then declines as flow rates rise further.
Peripheral  the outside area of something, or around the outside. A pump that uses an impeller with teeth around the outside to move water around. Also known as regenerative or regenerative turbine pump. These are low capacity high head pumps.
Impeller the vaned rotating disc in a pump. The rotating part of a centrifugal pump, compressor, or other machine designed to move a fluid by rotation.
Single Impeller Pumps Single pumps are designed to boost single water supplies; hot, cold or pre-mixed.
Multistage  Pumps These pumps have multiple stages, which increase pressure, good for long distances etc
Sump A hollow (hole) or depression in which liquid collects. Commonly a hole in the ground (a sump hole).
Check Valve a non-return valve that allows the flow of liquid through one way. Once the flow has stopped the valve shuts to stop any liquid back-flowing.
Pump Controller Automates the operation of a pump and protects against dry running.
Pump Switch Automates the operation of a pump.
Dry Running When the pump is running but there is no fluid going through it – this causes irreversible damage to the pump


What is Suction lift..?

Suction lift refers tot he partial vacuum that pumps create into which atmospheric pressure pushes water via the suction pipework. A maximum suction lift of 6.7 meters at sea level is common but this can be affected by the following :-

  • Friction loss reduced the vertical lift possible
  • Altitude, as this increased the atmospheric pressure decreases and less push is exerted on the water entering the pump suction
  • Pump suction performance, a better performing pump with a higher flow rate will mean less partial vacuum is created
  • Water temperature, suction lift can be reduced due to higher water temperature as it is more likely to boil when exposed to partial vacuum

What is Friction Loss..?

Pipe friction loss refers to the resistance to flow caused by the diameter of the pipe. The smaller the pipe, the more friction, which equals less flow. It is better to use the largest practical pipe size to avoid losses in pump performance.


Average Water Requirements

1/2" Tap   12 to 15 LPM @ 20 PSI (140 KPA)
Shower   15 LPM @ 20 PSI (140 KPA)
Lawn Sprinkler    15 LPM @ 20 PSI (140 KPA)
3/4" Hose & 1/4" Nozzle   40 LPM @ 30 PSI (210 KPA)
1" Hose & 3/8 Nozzle   75 LPM @30 PSI (210 KPA)


Note - These are average water requirements and may vary according to specific applications 


Flow Conversion

7.6 0.13 0.45 1.7 100
10 0.17 0.60 2.2 132
16.7 0.28 1 3.7 220
45.5 0.76 2.73 10 601
60 1 3.60 13.2 793
75.7 1.26 4.54 16.7 1000
83.3 1.39 5.00 18.3 1101


Pressure Head Conversion

Metres KPA BAR Feet Head PSI
1 9.81 0.10 3.28 1.42
10 98.1 0.98 32.8 14.2
10.2 100 1 33.4 14.5
15.2 149.5 1.5 50 21.6
30.5 299 3 100 43.3
35.2 354.4 3.5 115.5 50
70.4 690.8 6.9 231 100
101.9 999.6 10 334.2 144.7