Overview

The Jabsco V50AJ-115N-3A is a 12V variable-speed freshwater pressure pump for boats that need steadier flow than a fixed-speed pump can usually maintain. It is rated for 5 GPM open flow and 40 PSI max operating pressure, and the control system changes motor speed as demand rises and falls across the boat.

In normal use, that means water at faucets and showers stays more even, with far less pulsing and water hammer. The five-chamber diaphragm layout with internal bypass also removes the usual need for an accumulator tank and gives this pump the capacity to serve up to five outlets in a pressurized freshwater system.

Key features

• Variable-speed pressure control changes motor speed to follow demand and keep outlet pressure more even at faucets and showers
• 5 GPM open flow and 40 PSI max operating pressure for pressurized freshwater systems
• Capacity for up to five outlets without the usual need for an accumulator tank
• Self-priming up to 8 ft dry and run-dry capable
• 12 VDC nominal operation with 9 to 15.5 VDC range, 12 A max draw at 40 PSI, and 15 A fuse requirement
• ISO 8846 ignition protection, IPX5 rating, thermal motor protection, and a noise-dampening baseplate with rubber feet
• Quick-connect ports with included 1/2 in and 3/4 in straight and elbow hosebarb fittings plus an included 40 mesh inlet strainer

Installation and setup

The pump uses quick-connect ports and comes with both straight and 90 degree hosebarb fittings, so it can be worked into common 1/2 in and 3/4 in freshwater plumbing runs. It has 12 in 14 AWG stripped-wire leads, so the wiring path and fuse protection should be planned before final mounting.

Leave extra room around the body for port clips, wire bend radius, fittings, and hose turns before the mounting position is fixed. The inlet strainer should sit ahead of the pump so debris is filtered before it reaches the check valves and pressure-sensing components.

Compatibility and fit

This model is built for marine diaphragm pressure systems, with inlet pressure up to 30 PSI, fluid temperature range from 32°F to 140°F, and intermittent-duty operation. It self-primes up to 8 ft dry, which helps when the tank sits below the pump or the suction line is not already full.

The overall envelope is about 9.13 in long, 6.10 in wide, and 5.48 in high, so it fits best in a protected locker, utility space, or service compartment where the strainer can still be cleaned. The wetted path uses glass-filled polypropylene, Santoprene, and EPDM, while the pump also uses stainless steel fasteners, a cast aluminum lower housing, and a coated steel motor casing.

Use on board

This pump makes sense on cruising boats with galley, head, and shower demand on one freshwater circuit, especially when the goal is quieter operation and pressure that feels more even at the tap. It also works well in refits that are moving away from a fixed-speed pump and separate accumulator tank.

What's included

• Sensor-Max II 12V 5 GPM 40 PSI pump unit
• Two 1/2 in straight hosebarb fittings
• Two 3/4 in straight hosebarb fittings
• One 1/2 in elbow hosebarb fitting
• One 3/4 in elbow hosebarb fitting
• 90 degree quick-connect 40 mesh strainer
• Installation, operation, and maintenance manual