Jabsco Par-Max Series Pressure-Controlled Fresh Water System Pump

The Jabsco Par-Max freshwater pressure pump range provides automatic on-demand water delivery for boat taps, showers and appliances. This listing combines Par-Max 2, Par-Max 3, Par-Max HD4 and Par-Max HD6 models with 7.6–22.7 LPM flow, 25–40 PSI cut-out pressure and 12V or 24V supply options.

Each pump uses a sealed pressure switch, self-priming diaphragm design, integrated bypass and quick-connect ports. Par-Max 2 and 3 suit compact systems, while the HD4 and HD6 use heavy-duty motors and cast-aluminium lower housings for higher-demand installations.

Product Identification

• Brand: Jabsco
• Product name: Jabsco Par-Max Freshwater Pressure Pump
• Models: Par-Max 2, Par-Max 3, Par-Max HD4 and Par-Max HD6
• Part numbers: 31295-3512-3A, 31295-3524-3A, 31395-2512-3A, 31395-2524-3A, Q401J-112S-3A, Q402J-112S-3A, P601J-215S-3A and P602J-215S-3A
• Product category: Pressure-controlled marine freshwater delivery pump
• Output range: 7.6–22.7 LPM
• Voltage options: 12V or 24V
• Quantity supplied: One pump package

What Is a Par-Max Pump Used For?

It supplies pressurised fresh water from an onboard tank to taps, showers and compatible appliances. The integrated pressure switch starts the pump when an outlet opens and stops it when the system reaches the model-specific cut-out pressure.

What Is Included?

• One Par-Max pump in the selected output, pressure and voltage
• Model-specific 40-mesh inlet strainer
• Quick-connect hose-barb fittings stated in the specification table

What Is Not Included?

• Freshwater tank, accumulator tank or water-pressure regulator
• Hose, clips, shut-off valves or distribution manifold
• Electrical switch, fuse holder, circuit breaker or cable extensions
• Additional quick-connect fittings not stated for the selected model

How Do I Select the Correct Par-Max Model?

Estimate simultaneous demand and allow approximately 3.8 LPM per typical outlet as a starting point, then confirm the desired pressure and pipe size. Par-Max 2 supplies 7.6 LPM at 35 PSI; Par-Max 3 supplies 11.3 LPM at 25 PSI; HD4 supplies 15.1 LPM at 25 PSI; and HD6 supplies 22.7 LPM at 40 PSI. Select 12V or 24V to match the boat.

What Is the Difference Between Standard and HD Models?

HD4 and HD6 use heavy-duty motors and cast-aluminium lower housings for longer life under higher flow and pressure loads. They also draw more current and require larger wiring and circuit protection than the smaller models.

Will an Accumulator Tank Improve the System?

An accumulator can reduce pump cycling, smooth flow and provide a small reserve of pressurised water. The Par-Max range already uses an integrated bypass to improve flow control, but an accumulator may still be beneficial in installations with low-flow outlets or frequent short demands.

Installation and Safety

Mount the pump in a dry, ventilated location close to the tank, using the vibration-damping feet and leaving access to the inlet strainer. Keep the suction line short, fit the correct fuse close to the supply and size cable for the total circuit length. Use potable-water-compatible hose and fittings, flush the system before use and do not connect a 12V pump to 24V.

Maintenance

• Inspect and clean the 40-mesh inlet strainer regularly.
• Check quick-connect fittings, hose clips and pipework for air or water leaks.
• Investigate rapid cycling, pressure loss, repeated fuse failure or unusual noise.
• Drain or protect the pump against freezing during winterisation.
• Sanitise the freshwater system using products and concentrations suitable for the pump and plumbing materials.

Key Features

• 7.6, 11.3, 15.1 and 22.7 LPM options
• 12V and 24V variants
• Automatic sealed pressure switch
• Self-priming diaphragm pump
• Can run dry without damage
• Integrated bypass for smoother flow and reduced cycling
• Quick-connect ports, strainer and hose-barb fittings included
• Heavy-duty construction on HD4 and HD6

Frequently Asked Questions

Which model is suitable for one or two outlets?
Par-Max 2 or Par-Max 3 may suit a compact system, but final selection depends on simultaneous demand, pressure preference, pipe size and appliance requirements.

Can the pump run dry?
Yes, the Par-Max diaphragm design can run dry without damage, but faults that leave the pump running continuously should still be investigated.

Do I need the supplied inlet strainer?
Yes. Install the specified strainer before the pump to protect the valves and pressure switch from debris.

Can I select a 24V pump for a 12V boat to reduce current?
No. The supply voltage must match the selected pump model.

Specifications

Open-flow ratings do not equal installed delivery. Actual flow depends on outlet pressure, pipe size, lift, restrictions, simultaneous demand and electrical voltage at the pump.

Open-flow ratings do not equal installed delivery. Actual flow depends on outlet pressure, pipe size, lift, restrictions, simultaneous demand and electrical voltage at the pump.