Getting water out of a thin bore well is impossible without a pump. Your pump is the centerpiece that connects you to the seemingly endless supply of underground water. Well maintained pumps will serve you for long but they all have a lifespan that varies depending on a couple of factors.
Well pumps last between 7 to 16 years depending on the type, model and use case. Reputable brands will list a duty cycle rating on the specs sheet giving you a rough idea of how long your pump will last if you know your average daily cycles.
Electric Submersible Well Pump Lifespans
Electric well pumps are the most common in shallow and deep wells where the user wants running water. Expect around 8 10 to 15 years from 3 Phase AC pumps and 8 to 13 years from a Single Phase AC pump.
DC pumps (Solar Water Pumps), on the other hand, are more efficient and resilient. A good quality DC well water pump can last anywhere between 15 and 20 years. Their lifespan and efficiency make them a good idea in an off grid setting. This extra performance is worth the extra dollars you will pay since DC pumps are more expensive that their AC counterparts.
Your Pump’s Lifespan Depends on How Often You Cycle it
Estimating a well pump’s lifespan by years is less accurate than using the ‘Duty Cycle’ given by the manufacturer of the specifications sheet.
A cycle involves switching on a pump, letting it run and shutting it down again. The duty cycle rating determines how many times the manufacturer thinks you can turn the pump on, let it run and off before it fails.
This means that reducing the number of cycles in a day can significantly extent your well pump’s lifespan. Some of the things you can do to achieve less cycles per day include:
- Installing a big enough pressure tank that increases how much water the pump pulls per cycle. A bigger tank will provide you with water for hours before you call on the pump to fill it up again
- If you want less cycles, you can hook up your well system to an elevated water tank that you can fill up in a single cycle and use gravity to feed water back to your house or garden. This approach can easily give you a single cycle per day if you size the tank well. The pump might run for longer but this is less harmful than short cycling it
Run Your Pump Within its Recommended Operating Range
Sticking to a pump’s specification, especially on the lifting depth and water head capacity is a good way to avoid overworking the system. Go for a pump that can lift handle the effective vertical distance between itself and the pressure tank (or your storage tank if you pump into a gravity feeding tank.)
Keep Sediments and Silt Off the Well
Dirt is bad news to an impeller. Any sediments or silt in the water will abrade the fast moving impeller blades wearing them sooner. It could also affect the pump’s bearing making them fail long before your pump exhausts its estimated duty cycle.
Keep a Close Eye on the Water Table
Well pumps use the water they move to lubricate and cool their moving part. Running a dry pump will lead to overheating and catastrophic failure. Getting a system with protection switches and controls is a good way to automate the process. Some circuitry gets this done by monitoring how much current the pump is drawing.
When the pump isn’t moving any water, the blades spin freely hence the pump needs less power to keep them going. Consequently, its amperage draw on the power supply drops. A circuit that can monitor this dip and shut down the pump can be a rudimentary protection against running your well pump dry.
Don’t Overwork the Pump
The last trick to getting the best lifespan out of your pump is choosing a system big enough for your size. A small system that cycles more often or runs for longer to meet your needs will definitely age faster than a well sized system that meets your needs without working at its absolute performance limits. The bigger pump might cost more to buy but it will serve you for longer than a smaller struggling unit.
Why Solar Powered Pumps are a Better Idea
Solar powered pumps(DC pumps) will always be the best for an off the grid homestead. Even though they are more expensive than AC pumps, they are more efficient and easier to run. Their top advantages include:
No Need for Expensive Circuitry to Run
You won’t need an expensive DC-AC power inverter to run the pump. Some can run straight from solar panels since they have an inbuilt control box that manages over voltage, under voltage and power tracking. All you have to do is ensure you connect them to an array that matches the stipulated power needs.
Moreover, the fact that you don’t have to run your solar, wind or hydro power through an inverter to power the pump means:
- You won’t waste energy in the AC to DC conversion
- You don’t have to oversize your main power system to accommodate the pump. It can run on its own panels
- You will not have to accommodate its draw when sizing your solar system charge controller
- If you have to tie them to your house batteries in winter or gloomy days, you can still use a more efficient DC to DC converter and bypass the AC inverter
Since DC pumps are more efficient, you will always get more water per KWH compared to what you would get from an AC pump even if we ignored the losses incurred in converting your DC power to AC.
A well-sized well pump from a reputable manufacturer should be good for an average of 20 years. You still have to check on it on regular basis and pay attention to any performance dips as they might hint on problems that will ruin your trusty pump if you don’t sort them sooner than later.
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