How to Select a Submersible Bore Pump

Working Out Which Size Submersible Bore Pump Is Needed

 

There are 2 things we need for the selection of submersible bore hole pumps:

1 – What is the Total System Head Required?

To Calculate the System Head Requirement, please visit our FAQ Page: Calculate Total Head

2 – Litres Per Minute (LPM) required

Work out how many litres per minute all your taps, sprinklers etc require. What is the maximum that you will be running at one time? Then add up the litres per minute to get a total. If you are unsure of how many LPM sprinklers and taps require, look on the sprinkler packaging or go to your local hardware shop and read the packaging as it will always be displayed. Eg: a large pop up sprinkler with a 24m diameter spray with a size 8 nozzle will require 12 LPM. If I used 8, then I would require 12 x 8 = 96 LPM

Selecting a suitable Bore Pump

You will need to go to the flow chart of the bore pump. Choose a flow chart that displays the models that will produce the amount of water you need. They are usually rated in LPM or m3/h.

LPM x 60 ÷ 1000 = m3/h

A flow chart will have the LPM or the m3/h across the bottom of the chart and the Head (m) running vertically on the left side of the chart.

bore pump selection flow chart

The chart below (figure 3) is for pumps rated at 18LPM.

Look along the bottom of the flow chart where the LPM are displayed and move to the 18LPM mark.

Now run a line vertically straight up to the efficiency curve. You will notice that the peak of the curve is at 18LPM.  I have marked the line in red for you to see.

For this example, we need a pump that will give us 20LPM @ 65m head.

bore pump flow chart figure 1

We chose the flow chart for 18LPM as it is close to 20LPM that we require.

If we follow the line up to the efficiency curve you can see that it is still around the top of the curve (and slightly to the right) which is good.

bore pump selection - how to read the efficiency curve figure 2

IMPORTANT – In the image below you can see the ‘Best Efficiency Range’ at the top of the chart.  There is also a ‘Pump Operating Range’.   If the pump is operating too far to the right or left of this range you can under load or overload the motor. Either will shorten the life of the pump and motor.

selecting the correct bore pump using a bore pump flow chart figure 3

The result of this example is that we would go with the 0.55kw – 13 model from this selection.

The Bore Pumps are displayed on this page ranging in Liters Per Minute (from the smallest flow to the largest flow).  When you click on a selected pump, you can view the Flow Curves for that range.  Eg, the above flow curve is for 18LPM bore pumps.

red_bar

bore_pump_150h

 

The OEM Bore Pumps are the cheapest on the site. They come with the option of an Automatic Control Box which has water level monitoring probes that go down the bore with the pump to monitor the water level. If there is not enough water, the system will shut down until the water level in the bore recovers and will allow the system to restart when the water level in the bore recovers. Handy if you don’t know the flow of the bore or have a low yielding bore.

3_pump_and_motors

 

 

 

The best value bore pump for sale is the Pentax Bore Pump coupled with a Franklin motor. This combination is massively reduced in price to be the best quality value bore pump for sale on the internet.
Franklin Motor protection is also available with the Pentax range.

 

wilo-pump-range

 

 

The Wilo-Emu German made bore pumps are equivalent to the Grundfos range in quality, design and flow rates.  They also have a very popular low-flow range that Grundfos don’t have.  These are excellent value for money pumps.