Jabsco Par-Max HD4 Fresh Water Pump, Q401J-115S-3A, 12V 4 GPM 40 PSI Self-Priming Diaphragm Pump

The Jabsco Par-Max HD4 Fresh Water Pump (Q401J-115S-3A) is a 12V diaphragm pump built to deliver on-demand freshwater supply for boats and RVs, moving 4 GPM (15 LPM) at up to 40 PSI. It uses a pressure-controlled diaphragm so the system behaves like a home water supply, cycling on automatically when a tap is opened and shutting off when pressure is satisfied, thanks to an integrated, sealed pressure switch.

This HD4 model steps up from Jabsco's standard Par-Max line with a heavy duty motor set in a cast aluminum housing for a longer working life under sustained high pressure, along with an integrated bypass module that reduces cycling and smooths out flow. Dampening feet under the pump reduce vibration for quiet running, and the pump is self-priming and can run dry without damage, which simplifies installation and protects the system if the supply line runs empty.

Installation and servicing are built around quick-connect fittings: the pump comes equipped with an inline 40 mesh quick-connect strainer to protect the diaphragm from debris, plus two 1/2 inch quick-connect straight hosebarb fittings for fast, tool-light hookup to existing freshwater plumbing. The housing is a black plastic construction paired with the cast aluminum motor housing, sized at 9.41 inches long by 3.9 inches wide by 4.23 inches high, and weighing 7.8 pounds.

Specifications

• Brand: Jabsco
• Manufacturer Part Number: Q401J-115S-3A
• Pump Style: Diaphragm
• Open Flow: 4 GPM (15 LPM)
• Voltage: 12 Volts DC
• Maximum Pressure: 40 PSI
• Strainer: Inline 40 Mesh Quick-Connect Strainer
• Hosebarb Fittings: 2 x 1/2 inch Quick-Connect Straight Hosebarbs
• Material: Plastic housing with cast aluminum motor housing
• Color: Black
• Product Dimensions: 9.41 inches L x 3.9 inches W x 4.23 inches H
• Weight: 7.8 pounds
• UPC: 671880841863
• Warranty: 1-year manufacturer warranty

Frequently Asked Questions

What flow rate and pressure does the Jabsco Q401J-115S-3A pump deliver? The Jabsco Par-Max HD4 Q401J-115S-3A delivers 4 GPM (15 LPM) of open flow at up to 40 PSI, running on a 12 volt DC supply.

Is this pump self-priming? Yes, the Q401J-115S-3A is self-priming, which simplifies installation since the line does not need to be manually primed before startup.

Can the pump run dry without being damaged? Yes, the Jabsco Par-Max HD4 Q401J-115S-3A can run dry without damage to the unit, protecting the system if the freshwater tank runs empty.

Does this pump cycle on automatically when a faucet is opened? On-demand operation is handled by an integrated, sealed pressure switch built into the Q401J-115S-3A, so the pump starts automatically when pressure drops and shuts off once it is satisfied.

What fittings are included with this pump? The Q401J-115S-3A comes equipped with an inline 40 mesh quick-connect strainer and two 1/2 inch quick-connect straight hosebarb fittings for connecting to existing plumbing.

What are the dimensions and weight of the Jabsco HD4 Par-Max pump? The pump measures 9.41 inches long by 3.9 inches wide by 4.23 inches high and weighs 7.8 pounds.

What is the housing made of? The Q401J-115S-3A has a black plastic housing paired with a cast aluminum motor housing for durability under sustained pressure.

How does the HD4 differ from Jabsco's standard Par-Max pumps? The HD4 designation on the Q401J-115S-3A means a heavier duty motor in a cast aluminum housing plus an integrated bypass module that reduces cycling and smooths flow, compared to Jabsco's standard-duty Par-Max models.

Is the pump noisy when running? No, the Q401J-115S-3A uses dampening feet under the pump body to reduce vibration and keep operation quiet.

What warranty comes with this pump? The Jabsco Q401J-115S-3A is backed by a 1-year manufacturer warranty.

What does the inline strainer protect against? The included 40 mesh quick-connect strainer on the Q401J-115S-3A filters debris out of the water supply before it reaches the diaphragm, protecting the pump from clogging or damage.

Is this a 12V or 24V pump? The Q401J-115S-3A is a 12 volt DC pump.