Ashcroft 81406XLL Pressure Gauge 3.5 in Dial Compound Psi

Product Description

The ASHCROFT 81406XLL is a compound pressure gauge designed for monitoring both vacuum and positive pressure in a single instrument. The 3.5-inch analog dial provides a clear, readable display across a compound range of 30 inches Hg vacuum to 0 to 15 psi. The dry, no-fill stainless steel case protects internal components in environments where liquid-filled gauges are not required or not permitted. Bronze wetted parts offer solid compatibility with common system fluids. Accuracy is rated at 1 percent of full scale, meeting standard requirements for HVAC, plumbing, and light industrial pressure monitoring applications. A licensed plumber, HVAC technician, or mechanical contractor typically handles installation in line service.

This gauge is suited for residential and light commercial applications where compound pressure readings are needed — such as suction-side plumbing systems, low-pressure fluid lines, or vacuum-to-positive pressure monitoring points. The center back mount configuration allows the gauge to be installed flush against a panel or directly into a manifold fitting. The 1/4-inch threaded connection is a common size found in HVAC service ports, plumbing test assemblies, and hydronic systems. No liquid filler means the gauge is appropriate for indoor panel mounting where leakage of fill fluid is a concern.

Key Features

• Compound range: 30 inches Hg vacuum to 0 to 15 psi on a single dial
• 3.5-inch analog dial for clear reading at typical service distances
• 1 percent of full-scale accuracy for reliable pressure verification
• Stainless steel case resists corrosion in demanding service environments
• Bronze wetted parts compatible with common system fluids
• Dry, no-fill construction eliminates risk of fill-fluid leakage on indoor panels

Compatibility

Designed as a standard OEM-style replacement or new-installation compound pressure gauge for residential and light commercial HVAC, plumbing, and mechanical systems using 1/4-inch NPT center back mount connections.

Installation Notes

Installation is typically performed by a licensed plumber, HVAC technician, or qualified mechanical contractor. Shut off system pressure and bleed the line to zero before removing an existing gauge or installing this one. Apply thread sealant tape or paste rated for the system fluid to the 1/4-inch male threads before threading into the port — do not over-tighten, as bronze connections can be damaged by excessive torque. Verify the pressure range of the system does not exceed the gauge maximum before returning the system to service.