Overview

The Attwood Marine 99IFDV00-1 is an integrated fuel demand valve for below-deck fuel systems. It keeps tank pressure from pushing fuel into the distribution line when the engine is off, so fuel reaches the engine only when there is actual demand. This version has a built-in manual override and the valve body can be oriented in 12 positions during installation.

For fit and system planning, it is rated for operating input pressure up to 138 kPa (20 psi) and protected for a 276 kPa (40 psi) pressure spike. Flow performance is listed at 200 L/H (53 GPH) at less than 2 kPa when used with a 1/2 inch pickup tube and matching barb. It is also compatible with ethanol-blended fuels.

Key features

• Integrated fuel demand valve for below-deck fuel systems
• Keeps tank pressure from pressurizing the fuel distribution line and engine side of the system
• Built-in manual override for service and setup
• Valve can be clocked in 12 positions to help with hose routing and tank layout
• Operating input pressure up to 138 kPa (20 psi), with protection for a 276 kPa (40 psi) pressure spike
• Flow performance up to 200 L/H (53 GPH) at less than 2 kPa in the stated test setup
• Compatible with ethanol-blended fuels
• Can eliminate the need for rigid fuel distribution lines in pressure-relief systems under ABYC H-24.15.9

Installation and fit

This valve is installed at the tank and uses a 1/2 inch NPT barb fitting or anti-siphon valve, which is not included. The mounting point should be flat and protected from twisting loads and foot traffic, which matters on boats where the tank bay is tight and service access is limited.

For replacement work, confirm the tank base, fitting thread, pickup arrangement, and overall fuel line layout before ordering. After installation, the system should be pressure tested to 3 psi for at least 10 minutes and checked for leaks by a method other than pressure decay.

Compatibility and use on board

This valve suits boats with permanently installed below-deck fuel tanks that use pressure-relief fuel system components and need tank pressure controlled before it reaches the engine side of the line. It is a sensible match for builders, service yards, and owners replacing a valve in a compatible Attwood integrated fuel setup where clean hose routing, manual override access, and ethanol fuel compatibility matter.