Reviewing the Basics

Published On: February 19, 2024By Categories: Features, Pumps and Water Systems, Workforce Development

It’s important to cover the basics of submersible pump installation.

By Daniel Featherstone

Figure 1. Stranded wire.

You will notice a trend if you have been to any gathering or convention in the well water industry: We are an aging industry, and we are racing to pass on our knowledge to the many new faces entering the field.

We have a responsibility to do so in a responsible manner. What could I mean? Many of us have habits, assumptions, and shortcuts when it comes to dropping a new pump. Those of us with the experience can pass on a lot of good knowledge to the newcomers.

But we can also forget the basics—the assumed steps we veterans just know. That is why it is often good to review the basics of pump installation and make sure the foundation is set properly for those we train and work with. With that being said, let’s review the basics of a submersible pump installation and answer some common questions.

Where to Start

A good place to start is splicing, something done more times than one can count and a process that muscle memory takes over and is eventually done with little thought. But a splice can make or break a system and a splice can create an immediate failure or an issue down the road that will have to be addressed.

Butt connectors are now standard in the industry. Take time to make sure the wire is stripped sufficiently to ensure the insulation is not part of the crimp. The exposed wire should overlap a touch once in the butt connector, and once crimped, pull on the wire to ensure a secure connection.

Heat shrink tube should be the submersible type, and a good seal will see the inner sealant evenly bead around each end of the tube, ensuring a tight seal. It is also recommended to use waterproof rubberized electrical tape about 4 to 6 inches each way from center.

Why so careful? My mother had a saying I have passed down to my son: “Do the job right the first time so you don’t have to do it again.”

Figure 2. The service entrance of a water well system.

The industry standard is stranded wire. Stranded wire (as seen in Figure 1) has spacing. This spacing can create capillary action—literally pathways for water to be siphoned into the cable and oxidize the copper, leading to premature failure.

Once you have completed the splice, a simple megohmmeter is the best method for testing your work and takes but a few seconds. I recommend setting the splice in a bucket of water as well to “wet test” the splice.

Do you do a megohm test as you drop the pump? By testing the splice right away and as you drop the pump, you are being proactive. Nothing is more costly to a job than to set the pump, have an issue, spend time troubleshooting the issue, and end up having to pull the pump because the wire or splice was compromised.

Setting the Pump

Do you use a torque arrestor setting the pump? (Figure 2) Centering guides? I know these questions can divide the reading audience, but the simple fact is a pump suspended by any pipe has torsion. This movement should be controlled to prevent damage to the motor and the wire going up.

The other factor is water surge on startup. This travels up the pipe, and again no matter the material of construction of the drop pipe, there is movement. And the deeper the set, the more movement or deflection of the drop pipe.

Before setting the pump, inspect the pitless adapter. Ensure the seal and surface is clean and free of debris. Once set, inspect for any leaks. Finally, the wellhead. How old is it? Is the seal and sealing surface clean and in good condition?

Is the head found on the well an older style that may be prone to debris or intrusion from say insects or other creatures? Does it still meet the current code? This is not just a cap but a health and safety point. Limit your liability and be sure the cap is properly fit and secure and updated if needed.

Now that we have the installation in place, how does it run? When cycling the system, how is the well reacting?

Next, what about the buried wire? Many of you may be asking, “Should we have thought to check that sooner?” and the answer is yes, we should have. It could have been the first thing done even before splicing. This is often an overlooked step and people often assumed all will be fine. But we all know what happens when you assume.

Ask yourself how old is the well? Is there any record or sign that the wire has been replaced recently? When in doubt, test. The good old megohm test can take care of the wire quickly and easily. If you do not have a meter and are suspicious of the buried wire, run a temporary wire run above ground and run the system.

Where buried wire often becomes an issue is with the use of a variable frequency drive. Wire issues can trigger ground faults, amp issues, or short faults to trigger the VFD to fault.

By now, you have probably noticed I think it is a good idea to invest in a megohmmeter if you have not already done so.

Figure 3. Calculating run time.

The Service Entrance

Now let’s turn to the service entrance of the system (Figure 2). The pipe coming in often runs to a tank tee with ports for a drain cock, pressure switch, pressure gauge, and pressure relief valve.

Let’s start by discussing the tank tee. It can be problematic at times if you are running a VFD. Remember the transducer is looking for laminar flow and the very nature of a tank tee creates turbulence.

The transducer will ideally be after the tank, which is the buffer controlling start surge and water hammer that may be present on the incoming side of the system. So, ideally, the transducer should be a minimum of 18 inches away from the tee.

Yes, I know this is difficult, and you’re thinking, “Who really does this?” If you must put the transducer on the tee, use a snubber that will function as a water hammer device and force the water to appear steady or laminar.

Other things to consider on the tank tee connection are the drain cock/test cock placement. The best practice is to know and follow code.

Another item to highlight is the pressure relief valve. Some codes require one be installed. Should you fall into the category that a pressure relief valve is not needed, let me get on my soapbox for a moment advocating for one. Pressure relief valves CYI (cover your interests). They are cheap insurance.

Even if code does not require one, I recommend one for any pump installation: jet, irrigation, or submersible. When controls fail, you need this safety.

Think of this scenario: “Your honor I chose not to install a reasonably costing safety device to protect the homeowner’s finished basement.” Do not put yourself in that situation. And do not forget to plumb it per code, but also to where the water can run when the relief opens, ensuring to not flood and damage property. Code usually allows you to plumb it out of the home or structure safely.

Control Box Thought

Let’s circle back and talk about a three-wire control box. Which is still the most popular control box installed for a 1 hp or smaller pump? The induction-run control box. Why? It’s cheaper. There is not one other advantage; it’s simply cheaper.

With a cap run box, you have more cost, but those can be offset by lower amp draw, potential savings in wire, and a cooler motor operation that can potentially lead to longer life of the motor. I could go on, but to be honest that is easily an article unto itself.

Running the System

Now that we have the installation in place, how does it run? When cycling the system, how is the well reacting?

What if you find the well does show significant drawdown when running? The first thought should be what did the well report show for flow? Should you find yourself in a low yielding well situation, just how bad is the situation?

Figure 3 is a worksheet to calculate run time given the well production and flow of the pump. This comes from the Water Systems Council training handbook. Again, this could be a discussion all to itself, but here are some quick takeaways.

First, you will be surprised at just how much water can be stored in the well. Second, remember pressure tanks add to the storage. Third, flow and pump can be monitored and controlled.

Yes, you can do so by controlling the flow with valves or flow restrictors limiting the gallons per minute. You can control the pump by monitoring the flow and the pressure. From the simple mechanical low flow switch to electronic controls, intelligent pressure switches, and of course a VFD, you can control and monitor. And yes, this too could be another discussion.

Let’s not forget to talk about another key part of the system: the tank. Traditional sizing rules are to find the gallons per minute of the pump, and for a 1 hp and smaller motors, match the gallons per minute to the drawdown of the tank. This ensures a one-minute run time to help better cool the motor.

For a 1.5 hp or larger motor, double the gallons per minute of the pump and match that to the drawdown of the tank or tanks if needed, giving you a two-minute run time. The longer the pump runs with flow, the better the cooling to the motor.

So how about when running a VFD in the system? Traditionally, the tank size, not drawdown, should be 10% of the gallons per minute of the pump but no smaller than a 2-gallon tank.

Can I take a moment to address that standard? Go no smaller than a 5-gallon tank. Why? There is little drawdown in a 2-gallon tank, and do you know how much air is in the tank? Not much is the answer.

That can lead to waterlog issues quickly and a service call just to check and pressurize that 2-gallon tank. This is why I recommend going no smaller than a 5-gallon tank. The better answer is the larger, the better. A larger tank has the potential of more storage should the customer lose power. It also allows for less starts for the motor and provides a longer run time to cool the motor more efficiently. I am sure you get the idea.

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So, as we come to the end, I hope I have highlighted the need to remember the foundations of what a good installation should be.

It is good to know why you are doing this step or that shortcut. It is helpful when showing and training others and ensuring we are not falling in the trap of assuming that new hire “will just know.”

I hope I showed just how important splicing is and how to keep the motor and wiring protected in the casing. I hope I relayed moving away from always using a tank tee as it can cause an issue with a VFD reading pressure.

And control boxes? Please take a good look at a cap run control box when installing smaller than a 1.5 hp motor. I hope you will think about how to best address a low yielding well. Just motor protection? A flow control? Both?

Always remember to review the basics from time to time. Remember teaching the foundations of what we do is the answer to our industry’s future well-being.


Daniel Featherstone is a technical training leader for Pentair Flow Technologies. He has been with Pentair for more than 23 years and training for more than 20. His experience includes a variety of pumps from standard centrifugal and submersibles to vertical multistage and vertical line shaft turbines, and more.

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