Installation

The largest area on this exam — 15 of 30 questions. This endorsement is about single-phase submersible and jet pump systems, so the electrical side matters as much as the plumbing.

Two-wire vs. three-wire motors

	Two-wire	Three-wire
Conductors (plus ground)	2	3
Starting components	Built inside the motor	In an external control box
Control box required?	No	Yes
Servicing starting parts	Must pull the pump	Done at the surface

The control box must match the motor's horsepower and voltage exactly, and be the same manufacturer as the motor. A mismatch causes premature failure of the box or the motor. Because the box holds the start capacitor and relay, three-wire systems can be troubleshot at the surface — a real advantage on deep sets.

Franklin also notes that for engine-driven generators, a two-wire motor needs a generator rated about 50% higher than a three-wire motor of the same horsepower, because of its starting characteristics.

Electrical requirements

• Voltage: operate within ±10% of the motor nameplate rating.
• Amps: never exceed the maximum amps on the nameplate.
• Insulation resistance to ground, measured at 500 volts with a megohmmeter:
  • before the motor is submerged: at least 200 megohms;
  • after it is submerged: at least 0.5 megohm (500,000 ohms).
• Drop cable must be sized for both the load and the length of the run. Long sets need larger wire to hold voltage drop within limits — undersized cable is a leading cause of motor failure.
• Grounding must meet the National Electrical Code and local codes.
• Every submersible motor requires a dedicated surge arrestor. Motors 5 hp and smaller marked "Equipped with Lightning Arrestors" have one built in. Mount it as close to the motor as practical and ground it below the lowest drawdown water level.
• Splices in the drop cable must be properly insulated and watertight — heat-shrink or potted kits made for submersible service.

Setting the pump

• Set the pump above the well screen and off the bottom so it cannot run dry or draw sand, and below the lowest expected pumping level with margin.
• Motor cooling comes from water flowing past the motor. In oversized casing — or where the pump must set below the screen — install a flow sleeve (shroud) to force water past the motor.
• Check that the pump shaft turns freely by hand before installation and that it moves up about 1/4 inch when coupled to the motor.
• Assemble pumps and motors 5 hp and larger in a vertical position for correct alignment.
• Do not let the pump guard pinch the motor leads where they enter and exit.
• Support the string properly — never hang weight on the drop cable. Secure the cable to the drop pipe at intervals.
• Install a check valve. Check valves prevent backspin, upthrust, and water hammer when the pump shuts off.

Jet pumps

• Shallow-well jet: one suction pipe; the jet assembly is in the pump. Limited by atmospheric pressure to roughly 25 feet of lift at sea level. Goulds specifies that vacuum should not exceed 22 inches of mercury at sea level.
• Deep-well jet: two pipes, with the jet/ejector assembly down in the well.
• Jet pumps must be primed before starting — running one dry damages the seal and impeller.
• A foot valve at the bottom of the suction line holds prime.

Tank and controls

• Captive-air (bladder/diaphragm) tank: pre-charge to about 2 psi below the pressure switch cut-in, measured with the water drained out of the tank.
• Pressure switch: common settings are 30/50 or 40/60 psi (cut-in / cut-out).
• A waterlogged tank — one that has lost its air charge — causes the pump to short-cycle, which is the fastest way to destroy a motor.

Wellhead and finishing

• A pitless adapter takes the discharge out through the casing below the frost line while keeping the casing sealed.
• The well vent must be screened and turned down.
• Disinfect the well after installation or repair.

Sources: Franklin Electric AIM Manual — Submersible Motors (Application, Installation, Maintenance); Goulds Service Manual for Submersible and Jet Pumps; Groundwater and Wells, 3rd Ed., Chapter 12.