To decide which pump is right for your purpose you need the following information:
- Total borehole depth: Ground level to the bottom of the borehole. The pump must never be to close to the bottom otherwise it sucks up dirt & debris that clogs and breaks the pump. Tested by lowering a weight down the hole attached to a rope, when the weight hits the bottom the rope slacks.
- Water height in the hole: also known as standing height. This is the level at which water is found in the hole. The pump must be placed at least at this level, but draw down of the water level as well as seasonal variability must also be taken into account. Our pumps have dry run switch off protectors to avoid pump damage if they do run dry. Measured by dropping a Smallish rock down the bore hole and counting the seconds until it hits the water. The rock falls at 1 meter per second.
- Run in/tank height: The height of the tank, run in, dam, etc above ground. This has to be added to the lift requirement of the pump. Ground level to the highest point the water runs into the reservoir. Also referred to as tank height. The closer the tank/reservoir is to the ground the less the pump needs to lift and the more water it will deliver per hour.
- Total head: the total height from the run in to the submerged depth of the pump. This is one of the two most critical measures as it determines the pump sizing.
- Horizontal pumping distance: Add 5m of lift per 100m horizontal distance or if there is an incline add the height difference (E.g. 5 meter height difference over 200meter = +5 meter).
- Reservoir/dam capacity: Size of the tank, reservoir, dam, etc. The reservoir must be able to handle the daily delivery of the pump.
- Tested delivery capacity: What is the tested delivery capacity of the borehole, dam, put, well, river, aquifer, etc deliver per hour/minute? Keep in mind that a borehole can become a dry well if more water is pumped from it than can be replaced by the ground water sources. Please ensure a tested figure is provided.
- Amount of water required: This is the amount of water required on a daily/hourly basis. On average there is 7 hours of sunlight per day that the pumping system can work. Thus is you require 3500 liters of water per day, you divide it by 7 = 500 liters per hour required. An average household required +/- 3000 liters of fresh water a day.