Replacing a submersible well pump is not a complicated task and relatively simple if you understand the basics about a well system - like the placement of the pump, how the submersible pump operates and how it is installed in a well casing. An advanced do it yourselfer with knowledge of electrical wiring and some basic plumbing skills is probably capable of replacing a submersible irrigation pump. This is not a step by step installation guide but rather an overview for a general understanding to evaluate whether to do it yourself or hire a contractor. The savings on the cost of labor, if you do it yourself, will be about 50 - 60% of the total price of a contractor doing the job. The first factor in deciding whether to attempt doing it yourself is how deep the well is and do you have a large enough lay down area to layout the pipe in your yard once you start pulling it out of the casing. If your well is 50’ to 150’ deep, I would recommend doing it yourself if you are physically capable to continuously lift and pull about 40 to 70 pounds of weight and hold it in place for during the complete removal of pump to keep from dropping it back into the well. To do this you will need at least one other person to help you pull out the pump and guide the discharge pipe away from the well as you are lifting it out.
The well casing in made of steel, iron or PVC pipe usually 3"or 4" inside diameter and this acts as a sleeve in which the pump housing, discharge pipe and wiring go down to reach the water level within this pipe casing. Attached to the submersible pump is the discharge pipe, usually 1" to 1- ¼" flexible poly pipe and the electrical wiring which also runs into this casing to the depth of submersible pump in the well. The deeper the well, the heavier and more difficult it is to lift out. The weight of the pump assembly may require some rigging above the well casing to help lift and hold the pump assembly in place so it doesn't slip and drop back down into the well casing as you are pulling it out. Once you start pulling up of the pump you must continue the motion until it is fully out of the casing. If you are doing this manually attach a rope beforehand to the top end of well cap so the other person can easier hold on to it and tie it off to something - a tree or fence, in between lifts if you need to take a break and stop lifting.
If you decide to replace the well pump yourself, here are some tips to remember. Determine that the pump motor is bad by checking circuit breakers, switches and check that power is at the well head. If power is on at well head it is a good sign that the pump is broke. Turn off the power at the breaker panel, tag and lock it out for safety before you start exposing the well head. Clear the area around the well head, approx 6’ to 8’ diameter, of shrubs and plants so you have enough room to expose the pump outlet and electrical connections. Disconnect the discharge pipe and undo the wiring at the junction box near the top of the well. Loosen the bolts on top of the casing cover, this is a squeeze type of cover with a thick rubber ring that expands as tightened and contracts as loosened against the casing interior. Once loose, try to lift the cover, as you lift you will be getting an idea of how heavy the whole assembly is of which you have to lift out of the well.
Now you are ready to lift the pump. Rubber gloves, protective clothing or coveralls should be worn as the pump piping may have an iron and silt residue on the exterior and can be quite a messy job. Fasten a pull rope around the top of the well head for the other person to hold on and tie off if needed. Some wells may have a leader rope or cable already attached from original installation instead of relying on the discharge hose clamps and connection. The person who will do the actual pulling should stand directly above the well to lift the discharge piping straight out of the casing and the other person should stay with the top end of well cap and guide it to where you lay it down as you pull. Make sure that the person guiding the end has a good grip on the end before you release to get another grip. Continue until pump assembly is fully out of the casing and wash off the entire pump end so you read the specification tag of the pump.
Collect the information from the old pump - brand, model, HP, voltage, phase, 110/220, rpm, 2 or 3 wire configuration, continuous duty and the pumps outlet size and discharge pipe size. Most residential submersible pumps are either 2 wire or 3 wire configuration. The 2 wire type has 2 - 110v wires along with a case ground to pump housing. The 2 wire pump needs no controls. If it is a 3 wire pump you should replace the controls also.
Most submersible pump are two piece units bolted together to be one assembly and consists of the motor and the pump. You can just replace the motor or pump if you choose, but I would highly suggest that you replace the whole assembly. After you have identified what type and size pump you have you may want to decide to upgrade your system with a higher volume pump of keep the same configuration. For upgrading, you should contact a supplier or well contractor for recommendations to be compatible with your needs and piping sizes to which your pump feeds.
Installing the new pump assembly. Make an itemized list of new parts, controls, fittings or wiring as needed. If the existing wiring and flex pipe are in good condition there is no need to replace them. To install the new pump you will have to splice the electric wires together in a waterproof connection. Consult an electrician or well contractor to specify the power wire splice connector type and technique acceptable for well applications. Connect the pipe fittings and pipe clamps as directed in the manufacturer's instructions. Tape the power wires about every 2’ for the entire length to the flex pipe for ease in reinstallation of pump into casing. Turn the power to the pump on momentarily to check if it is working before inserting assembly into well. Turn the power breaker off and prepare to insert the pump back into the well again using 2 people - one at the well opening lowering and feeding the pump down and the other person at the well head cover feeding the slack to you and to help hold back to prevent the pump from dropping quickly down the casing.