Jabsco HD3 Par-Max 12V Fresh Water Pump - 3 GPM, 40 PSI, Q301J-115S-3A

The Jabsco HD3 Par-Max is a 12V diaphragm-type fresh water pump built to deliver on-demand water pressure for onboard plumbing systems, giving boaters a freshwater supply that runs like a home system. A pressure-controlled diaphragm and integrated, sealed pressure switch turn the pump on automatically whenever a tap or fixture opens, then shut it off once system pressure is satisfied. The pump is self-priming and can run dry without damage to the unit, so accidental tank depletion or air in the line will not harm the motor.

Construction centers on a heavy duty motor cast in an aluminum housing, built for a long working life under sustained high pressure. An integrated bypass module reduces cycling and smooths out flow delivery, while dampening feet at the mounting base cut vibration for quieter operation. Installation and servicing are simplified with quick-connect ports throughout: the pump comes equipped with an inline 40 mesh quick-connect strainer and two 1/2 inch quick-connect straight hosebarb fittings, so it drops into standard 1/2 inch water line runs.

Rated for 3 GPM open flow (11 LPM) at 40 PSI on a 12V DC supply, the Jabsco HD3 Par-Max suits galley, head, and shower plumbing on boats where a compact, quiet, self-priming pump is needed. It is part of the Jabsco Par-Max lineup, which also includes higher-flow HD4 variants for larger demand systems.

Specifications

• Brand: Jabsco
• Manufacturer Part Number: Q301J-115S-3A
• Open Flow Rate: 3 GPM (11 LPM)
• Voltage: 12V
• Pressure (Cut-Off): 40 PSI
• Strainer: Inline 40 mesh quick-connect strainer
• Hosebarb Fittings: 2 x 1/2 inch quick-connect straight hosebarbs
• Self-Priming: Yes, can run dry without damage
• Pressure Switch: Integrated, sealed
• Color: Black
• Material: Plastic
• Product Width: 4.29 inches
• Weight: 7 pounds
• UPC: 671880841832

Frequently Asked Questions

What flow rate and pressure does this pump deliver? The Jabsco HD3 Par-Max (Q301J-115S-3A) delivers 3 GPM (11 LPM) open flow at a 40 PSI pressure switch cut-off setting.

Is this pump self-priming? Yes, the HD3 Par-Max is self-priming and can run dry without damage to the pump, which protects it if a tank runs empty or air gets into the line.

What voltage does the Jabsco HD3 Par-Max run on? It runs on a 12V DC electrical system, standard for most boats with a 12-volt house battery bank.

What size hose fittings does it use? The pump ships with two 1/2 inch quick-connect straight hosebarb fittings, so it connects to standard 1/2 inch freshwater plumbing line.

Does the pump include a strainer? Yes, an inline 40 mesh quick-connect strainer is included with the Q301J-115S-3A to filter debris before it reaches the pump.

How does the pump turn on and off automatically? An integrated, sealed pressure switch on the HD3 Par-Max senses when a faucet or fixture opens and cycles the pump on, then shuts it off once line pressure is restored.

What is the housing made of? The HD3 Par-Max uses a heavy duty motor cast in an aluminum housing for durability, with a plastic pump body and black finish.

How much does this pump weigh? The Jabsco HD3 Par-Max weighs 7 pounds.

Is this a genuine Jabsco part? Yes, this is the genuine Jabsco HD3 Par-Max pump, part number Q301J-115S-3A, not an aftermarket copy.

How is this different from the Jabsco HD4 Par-Max pump? The HD3 Par-Max (Q301J-115S-3A) is rated for 3 GPM, while the Jabsco HD4 Par-Max line steps up to 4 GPM open flow, with versions available at 40 PSI or 60 PSI cut-off, for systems needing higher volume.

Will this pump cycle on and off frequently during use? No, the Q301J-115S-3A includes an integrated bypass module that reduces cycling and delivers a smoother, more consistent flow while a fixture is open.

Is the pump noisy when running? The HD3 Par-Max uses dampening mounting feet to reduce vibration, allowing for quieter operation compared to a pump without vibration isolation.