Plumbing a jet pump correctly is the difference between a reliable water supply and a constant call to a plumber. This guide walks through the entire process, from initial assessment to final testing, ensuring you install a system that delivers consistent pressure and efficiency.
Understanding Jet Pump Mechanics
A jet pump moves water by using a motor to drive an impeller, which creates a vacuum and draws water in through the inlet. This water is then expelled at high velocity through a jet nozzle located in the housing, creating a venturi effect that pulls more water from the well through a second pipe, known as the intake line. Proper plumbing requires matching this mechanical action to your specific water source and vertical lift requirements.
Pre-Installation Planning and Safety
Before touching a wrench, you must map out the entire system layout. Measure the distance from the pump to the pressure tank and to the final fixtures to size the discharge lines correctly. Crucially, you need to determine the well depth and static water level to verify that a jet pump is suitable, as they are generally limited to lifts of 25 to 100 feet. Always disconnect the main power supply at the breaker box and lock out the disconnect switch to prevent accidental startup during the installation process.
Required Tools and Materials
Primer and cement for PVC or appropriate pipe adhesive for copper.
Pipe cutter or hacksaw.
Adjustable wrenches and channel-lock pliers.
Teflon tape or pipe dope for sealing threaded connections.
Voltage tester and multimeter.
Footings or pump mounting pads for stability.
Plumbing the Suction Line (The Well Side)
The suction line is responsible for pulling water up from the well, making its proper installation critical to avoid air leaks. You must use heavy-duty, schedule 40 PVC or galvanized steel pipe for this section, as it withstands the vacuum pressure. Prime and cement all joints thoroughly, or thread and seal galvanized connections tightly, to prevent air from entering the system. The line must be primed with water before starting the motor, as a jet pump cannot prime itself and will overheat if run dry.
Connecting the Discharge and Pressure Tank
Once the suction line is secure, run the discharge line from the pump outlet to the pressure tank. Use a union fitting right at the pump outlet; this allows you to easily disconnect the pump for maintenance without cutting the pipe. Size the discharge line one size larger than the pump outlet—typically 1.5 inches for most residential jet pumps—to minimize friction loss and ensure maximum head pressure. Secure the line with sturdy hangers every 4 to 6 feet to prevent sagging and stress on the pump flange.
Pressure Tank and Check Valve Installation
The pressure tank acts as a storage vessel and pressure regulator, cycling the pump on and off to conserve energy. Install a check valve on the line leading from the pump to the tank; this prevents water from flowing back down the discharge line when the pump shuts off, which would cause the system to lose its prime. Set the air charge in the tank to match the pump’s cut-in pressure, usually around 20 to 40 PSI, using a standard tire pressure gauge and an air compressor.
Electrical Connections and System Testing
Wire the motor according to the terminal diagram located on the pump housing, ensuring the ground wire is securely attached to the mounting bracket. After tightening all electrical connections, restore power and use the multimeter to verify that the motor is drawing the correct amperage. Turn on the water supply to the well and open a faucet slowly to allow the system to fill. Check all joints for leaks, and if the pump hums but does not pull water, you likely have an air leak in the suction line that must be repaired immediately.
