How to read a Flow Chart to Working Out What Bore Pump I Need
There are 2 things we need for the selection of submersible bore hole pumps:
- Total System Head required
- 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 you are using 8, then you would require 12 x 8 = 96 LPM
Selecting a suitable Bore Pump
At the moment we have only 4” inch bore pumps on the website.
Step 1 – Choose a BRAND
Step 2 – Next, select either SINGLE PHASE or 3 PHASE
Step 3 – Select the approx FLOW in LPM that you may require
Step 4 – Once you have done all this and have clicked on a pump that suits all the above criteria, you will need to go to the flow chart of the bore pump. You can see the flow charts when you click on a pump model. Alternatively, view the flow charts here:
- Franklin Electric Flow Chart
- Pentax Flow Chart
- Wilo Flow Chart
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.
Example of a Bore Pump selection
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.
For this example, we need a pump that will give us 20LPM @ 65m head.
We chose the flow chart for 18LPM as it is close to 20LPM that we require.
Below – 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 ideal.
You will notice that the peak of the curve is at 18LPM. I have marked the line in red for you to see.
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.
In this example we need a pump that will give us 20LPM @ 65m head, so we would go with the 0.55kw – 13 model from this selection.
When you click on a selected pump on this website, you can view the Flow Curves for that range. Eg, the above flow curve is for 18LPM bore pumps.