When establishing your off-grid homestead, a well is a necessity. A reliable source of clean water will help you be self-sufficient. Selecting and installing a solar well pump is a big project, but you can do it with some help. The most challenging part of the project is determining the best pump for your well. Every situation is different. There is no right or wrong configuration. The system that works for you is the best choice.
Know Your Well
You must understand your well before choosing a pump system. The static water depth, drawdown, and recovery rates impact the pump selection process. You can find this information by reading the driller’s report. Be sure to request the tests when scheduling your well drilling.
The depth of your well is only part of the calculation when determining the size of the pump required. The total head is the elevation from the static water level to the highest point of the discharge pipe. If your discharge is not at the wellhead, your total head may be greater than you suspect. A discharge pipe that travels over hilly terrain or for a very long distance will impact the total head of you well system.
Selecting Your Pump
There are several types of well pumps on the market. Each has benefits and drawbacks. Your choice will be based on the well characteristics and your water demands.
Well Characteristics That Impact Pump Selection
- High Static Water Level = Lower pump power required.
- Deep Static Water Level = High pump power required.
- Quick Recovery Rate = High volume pump rate.
- Slow Recovery Rate = Low volume pump rate.
- Total head from well to use location.
The ideal well has a high static water level and a quick refresh rate. This condition will require a lower power pump and a high pump rate. Due to the potential for fluctuating water levels, it is best to set the pump as deep as economically feasible.
Water Demand And Its Impact On Pump Selection
The water demand is the amount of water you will need at peak usage. This number is essential when sizing the pump and determining the system voltage. If your demand is low, a low volume pump may be all that is needed. Higher demand will require a higher volume pump system or a storage facility. There are several use factors to consider.
- Number of people.
- Consumption per person.
- Food Preparation.
- Toilets used.
- Hygiene: Showers, baths, general clean-up.
The amount of water to be pumped must exceed the amount of water required daily or weekly. A “slow” well may need a storage facility to accumulate water over time.
Pump Types and Applications
Once you have established the ideal pump depth and demand, you can select a pump type. Each pump type will cover a wide range of applications. The best option is a pump that exceeds your ideal depth and a pump rate (in gallons per minute) lower than the groundwater recovery rate. The pump that meets those specifications will supply the water you need without running dry and damaging the pump.
These pumps are designed to pump water from deeper than 200 feet. They must be completely submerged in the water to work. The pump is attached to a long power cable that goes up the well and to the power source.
- The submersible pump is durable and can handle sand, grit, and other debris.
- It can be automated and is easy to operate.
- It has a long life expectancy.
- Specifications are highly variable. Read carefully.
- Can be heavy and difficult to install.
- Quality varies significantly between brands.
- It can be expensive.
This type of pump is usually used for shallow wells. The pump is mounted above ground, and the water is sucked through a pipe that extends below the static water level.
- Inexpensive to purchase.
- Easy to install and operate.
- Lower power requirement.
- The pump may require priming.
- Can be susceptible to clogging.
- Less life expectancy than submersible pumps.
Drop Rod Pump
These pumps are a hybrid. The pump head is set at the ideal pumping level. The motor is mounted on the surface. Rather than a wire running to a submerged motor, a rod inside the riser pipe attaches the surface-mounted motor to the pump.
- Easy installation.
- Easy repairs and maintenance.
- No submerged electrical components.
- Manual operation is available.
- Shallow to 200-foot pump depth.
- Slow pump rates.
- Limited availability.
Choosing Your Power Source
Once you have chosen a pump, you must still make a couple of decisions. A solar well installation can use either a Direct Current (DC) or Alternating Current (AC) power source. A straight DC system is more straightforward. However, AC pumps tend to be more readily available and less expensive.
DC Pump System Electrical Component Options
A few component options are available when planning a DC well pump system. Some research will be required to determine the best configuration for your situation.
- 12 or 24-volt system. Lower voltage pumps will draw more current. Higher voltage pumps will require higher volt panels or 12-volt panels wired in series to achieve 24 volts.
- Batteries. Operation on overcast days or at night will require batteries.
- Charge controller. Safe and efficient charging of the batteries will ensure their reliability and longevity.
AC Pump System Electrical Components
An AC power system will include the same panels, charge controller, and batteries as the DC system. In addition, a power inverter will be required to convert the DC power to AC. While this is an additional expense, it may be a good investment if you already have an AC pump or desire an AC pump for some other reason.
Selecting Power Components
Once you know the power demands of your pump, it is time to design a solar system to supply the electricity. Three configurations can be applied to a solar well system.
Straight DC System
There are two straight DC configurations. The first is to wire solar panels directly to the pump. The second includes batteries. Both have their benefits and drawbacks.
The most basic configuration is to run the pump directly from the solar panels. The panel operating voltage (12 or 24-volt) must match the pump voltage. Most DC pump motors have an operating voltage range. For example, a 12-volt motor may accept voltage from 12 to 16 volts. The watt rating of the panel array must exceed the watt rating of the pump.
- Fewest components.
- No battery maintenance.
- No battery dependence.
- Least expensive.
- Only operates in full or near full sun.
Solar With Batteries
The more common DC configuration includes battery backup. This enables the pump to run day or night and during inclement weather. A battery bank of the same voltage as the pump is required. Higher power panels can be utilized if an MPPT Charge Controller is included in the system.
- Can be operated at night (with an adequate battery bank).
- Pump not impacted by cloud cover or inclement weather.
- More components.
- Battery maintenance.
- More expensive.
Solar DC/AC Hybrid
This is the most complex and expensive configuration. The system requires the same DC components as the Solar with Battery configuration and a DC/AC power inverter.
- 120 or 240 Volt AC power options.
- More pump options are available.
- Day, Night, Inclement weather operation with an adequate battery bank.
- Most components.
- Least self-reliant.
Installing the Solar System
The number of variables makes this part of the discussion tricky. Instead, here are some things to consider when installing your solar array and other power components. Review each owner’s manual as you collect components to ensure all devices are compatible and will do the job you need them to do.
- Ground mount array vs pole mount vs roof mount.
- Southern exposure.
- Grounding of the array.
- Adequate wire gauge.
- Weatherproof enclosure for electronic components.
- Accessibility for maintenance.
Installing The Pump System
Once you have acquired the pump system components, it is time to install the pump. There is no one way it set a well pump. While wells are generally the same, every application is different. We will discuss the most common aspects of setting your pump. Read the manual for your pump for more precise details.
Typical Elements of a Drilled and Cased Well.
A drilled well will be lined with 4 inch PVC casing. The casing prevents material soil and rocks from dropping into the well over time. A steel shell is inserted to a depth of approximately 8 feet. This is known as the sanitary seal. In most cases, it will extend 18 inches or more above grade. The well cap will mount to the top of the sanitary seal.
Some Variations You May Encounter
Not every well driller follows the same practices. Likewise, not every municipal jurisdiction enforces the same code requirements. Before starting your installation, review the well casing and sanitary seal. Be sure you have the proper size of installation components before you begin.
- Sanitary seal diameter may vary. 6, 8, or 10 inches are all possible.
- Cold climates should have a pitless adapter below the frost line. Warm climates may not require a pitless adapter.
- If a pitless adapter is used, the riser pipe will not exit through the cap. It will go through the pitless adapter below the frost line.
- A concrete skirt may be poured around the sanitary seal. If not, a skirt is a wise addition. It will provide a stable work surface.
Preparing to Set the Pump
Before you begin, review each step of your installation. Ensure every component, fitting, connector, and tool is at hand.
Items Required for All Installations
- Proper type, diameter, and length of pipe.
- If a pitless adapter is installed, set the connection with an appropriate “T” handle wrench.
- Anti-siphon or one-way check valve to retain water in the discharge line.
- Teflon tape or thread lubricant of pipe connections.
Items Required for Submersible Pumps
- Proper gauge and length of wire.
- Appropriate wire connectors. (Butt connectors and solder)
- Waterproof shrink tubing, adhesive lined, water and corrosion-resistant.
- Waterproof tape to secure the wire to the riser pipe.
- Torque arrestor for pump body alignment and stability.
- Safety rope or cable and connectors.
Items Required for Surface Set Jet Pumps
- Mounting hardware to retain the pump.
- Fittings and clamps for drop pipe.
- Appropriate type, size, and length of drop pipe.
Items Required for Drop Rod Pumps
- Sufficient length or proper size and type of riser pipe.
- Medium strength thread adhesive for drop rod connections.
- Safety rope or cable and connectors.
- A good assortment of standard plumbing tools will be required.
- For deep-set submersible installation, a small boom crane or some other method of controlling the descent of the pump may be necessary. For shallow wells, the weight should be manageable by hand.
- For rigid drop pipe installations, a pipe clamp should be used to retain each section of pipe as it is lowered through the cap.
Complete as many of the installation tasks before starting the installation process. The less you have to think about while working down the well will be a benefit. Some tasks that can be completed before lowering the pump are listed here. This is by no means a complete list.
- Apply Teflon tape or thread lubricant to all threaded connections.
- Apply thread lock adhesive to any screws or connectors that require it.
- Install the torque arrestor on the first piece of the riser pipe.
- If poly tubing is used, uncoiling and straightening the tubing makes installation much easier.
- If rigid PVC or steel riser pipe is used, install end fittings as necessary.
- Route the power cable through the cap and make any electrical connections.
- Route the safety cord or cable through the cap and attach it to the pump.
Installing a Surface Mount Jet Pump
This is a general procedure for setting a surface mount jet pump. All of the required components should be included if you purchase a kit. If you bought only a pump, you will need to acquire the other components. Read descriptions closely. Each brand of cap and pump has features specific to the manufacturer. Every installation will vary.
Poly Tubing Installation
- Install the cap.
- Lower the tubing through the appropriate hole.
- Leave 2 to 3 feet of tubing extending above the cap for making connections.
- When at depth, secure the top end of the tube with appropriate fitting.
Rigid Drop Pipe Installation
- Adjust pipe retainer clamp in the cap to allow the pipe to slide freely.
- Place the pipe clamp tool.
- Lower pipe through the clamp until fitting rests on the pipe clamp tool.
- Tighten the tool.
- Thread the next section of pipe into the previous section.
- Loosen clamp tool to allow fitting through.
- Readjust clamp to allow the following section to pass.
- Repeat this process until all sections have been set.
- Tighten pipe retainer clamp in the cap.
The pump manufacturer will have included appropriate fitting and connectors or specified the correct fittings to use. Follow the instructions as closely as possible. As always, variations will be common.
- Mount the pump in the desired location.
- Attach drop pipe to the inlet of the pump.
- Attach discharge pipe to the output side of the pump.
- Connect power to the pump.
- Prime the pump if required.
Installing a Drop Rod Pump
A Drop Rod Pump has five components: the pump, the drop rod, the riser pipe, the cap, and the motor assembly. Some brands include rod aligners. All of the required components are provided by the manufacturer. The pump, pipe, and rods must be assembled and lowered into the well simultaneously. It is essential to develop a routine to ensure no items are missed.
- Assemble the pump components per the instructions.
- Use a “T” tool or other weight controlling device to lower the assembly.
- Secure the safety rope or cable after each section of pipe is installed.
- Double check each connection and fitting.
- Do not rush. It is a time-consuming process.
When the pump assembly is secured, attach the discharge line to the output of the pump assembly. The electrical power can now be connected. Follow initial startup instructions.
Installation of a Submersible Pump.
The installation of a submersible motor pump is similar to the drop rod process. The main difference is that a power cable replaces the rod. Either rigid pipe or poly tubing may be specified by the pump manufacturer. The motor-driven pump is considerably heavier than the drop rod pump. A mechanical weight control device is strongly recommended.
- Assemble the pump per the instruction.
- Make electrical connections if necessary.
- Secure the safety rope or cable.
- If a rigid pipe is used, engage the pipe clamp as each section of pipe is installed.
- Take special care to keep electrical wire, safety rope or cable, and tubing from bunching or tangling as work progresses.
- If a pitless adapter has been installed, use an appropriate “T” tool to connect it.
- If a top discharge is used, the riser pipe can be connected to the discharge line.
When the pump has been set, the electrical connections can be made. Submersible pumps require fuses or circuit breakers. Read and follow the pump manufacturer’s instructions when selecting electrical components.
If you have done a good job of investigating and researching, you will have a solar-powered well system to be proud of. It will give you decades of reliable service and safe water.