Overview

The Jabsco 18911-1030 is a replacement EPDM check valve kit for Jabsco diaphragm freshwater pumps. It is used in the pump head to maintain one-way flow and proper pressure in the system, which matters when a boat relies on steady water delivery at the galley, head, or transom shower.

This kit is used on Jabsco PAR-Max 1.9 and PAR-Max 2.9 pump families in the 31295 and 31395 series. For boats already running one of those pumps, it is a service part that helps restore normal pump operation without replacing the full unit. Matching the pump series before ordering is important, especially on older installations where the pump may have been changed at some point.

Because the valve material is EPDM, this kit belongs in water system service rather than fuel or solvent applications. It makes sense for routine maintenance when the pump has trouble holding pressure, loses prime, or shows signs of valve wear from normal use in a marine freshwater circuit.

Key features

• Replacement check valve kit for Jabsco diaphragm freshwater pumps
• EPDM valve material for water system service
• Fits Jabsco 31295 and 31395 series PAR-Max pumps
• Used in the pump head to maintain one-way flow and stable pressure
• Useful when servicing a pump instead of replacing the complete assembly

Compatibility and fit

This part is tied to specific Jabsco pump families rather than to a broad range of plumbing systems. The main fit point is the pump model already installed on board. It suits PAR-Max 1.9 and PAR-Max 2.9 units in the 31295 and 31395 series, so the most reliable check is the model label on the pump body or the existing parts list for that pump.

On a typical boat freshwater setup, these pumps are found feeding sinks, showers, and small pressurized water circuits. If the rest of the pump is still in good condition, replacing the valve kit can be a sensible repair when the issue is inside the pump head rather than in the motor, pressure switch, wiring, or plumbing.

Installation and setup

This is a service part for the pump head, so access is easiest when the pump is isolated from power and the water system is depressurized first. While the pump is apart, it is worth checking the head for debris and confirming the inlet side is protected by a clean strainer, since contamination in the water line is a common cause of valve problems on board.

After reassembly, the pump should be primed and the system checked for normal shutoff and steady flow at the fixtures. If a freshwater pump still cycles incorrectly after valve service, the next items to inspect are usually the pressure switch, diaphragm, plumbing leaks, and intake restrictions.

Use on board

This kit is a good match for boat owners maintaining an existing Jabsco freshwater pressure pump on a cruising boat, fishing boat, or dayboat with a compact pressurized water system. It is especially relevant when keeping a proven pump in service matters more than replacing the entire unit.