Conbraco 9858P-12 Redline Glass

The Conbraco 9858P-12 is a professional-grade 5/8" OD x 12" Redline tubular glass designed for high-visibility liquid level monitoring in boiler and pressure vessel applications. Engineered for precision, this borosilicate gauge glass features a distinct red line fused into the glass, which creates a magnifying effect when fluid is present, significantly improving readability from a distance. Rated for standard duty, this replacement water gauge glass ensures structural integrity under thermal stress and is compatible with most standard water gauge valves used in HVACR and industrial steam systems. When performing a water level glass replacement, ensure proper alignment within the packing nuts to prevent mechanical stress. This Conbraco glass tube provides the chemical resistance required for long-term exposure to boiler chemicals and high-temperature water. Technicians should verify that gauge glass dimensions match the existing 5/8-inch outer diameter and 12-inch length to maintain a pressure-tight seal during system operation.

Key Benefits

• Enhanced Visibility: The integrated red line provides a high-contrast visual indicator, making it easier to monitor water levels in poorly lit mechanical rooms.
• Thermal Resistance: Manufactured from borosilicate glass to withstand the rapid temperature fluctuations common in steam boiler environments.
• Standardized Fit: Nominal 5/8-inch OD ensures compatibility with a wide range of Conbraco and Apollo sight glass assemblies.
• Corrosion Resistance: Engineered to resist chemical etching from treated boiler water, maintaining clarity over the service life of the component.

Common Questions

How do I ensure a leak-proof seal when installing the Conbraco 9858P-12?
Proper installation requires using new EPDM or Viton friction washers. Tighten the gauge glass nuts by hand until snug, then give an additional quarter turn; over-tightening can cause the glass to crack under thermal expansion.

Can this redline glass be cut to a shorter length?
While it is possible to score and snap tubular glass using a professional glass cutter, it is recommended to use the factory-finished 12-inch length to ensure the ends are square and fire-polished for the best seal.

Is the red line on the inside or outside of the glass?
The red line is fused to the back of the glass tube. The refractive properties of the water in the tube magnify this line, making the fluid level appear much more prominent.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.