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The CROWN BOILER CR-GGW58-12 is a pack of 12 rubber washers designed to seal and support 5/8-inch OD gauge-glass tubes in boiler sight-glass assemblies. These washers are molded from heat-resistant elastomer suited for standard hydronic and steam boiler operating conditions. They create a reliable seal around the gauge glass, preventing leaks and maintaining fluid-level visibility. Licensed boiler technicians and plumbers install these washers during routine sight-glass maintenance or full sight-glass replacement. The pack-of-12 quantity supports technician stocking and reduces multiple service trips for a common wear item.
The CR-GGW58-12 washers are used in hydronic heating systems and steam boiler installations where sight-glass assemblies require periodic resealing. Sight-glass washers are a routine maintenance consumable — they harden or compress over time, leading to minor seepage around the gauge glass. Replacing them during any sight-glass service restores a proper seal and supports accurate water-level readings. These washers are appropriate for residential and light commercial boiler applications where 5/8-inch gauge glass tubing is installed.
Designed as an OEM-style replacement washer for boiler sight-glass assemblies using 5/8-inch OD gauge-glass tubing in residential and light commercial hydronic or steam boiler systems.
Sight-glass washer replacement is performed by licensed plumbers or qualified boiler technicians. Before servicing a sight glass, shut off the boiler, isolate the sight-glass valves, and allow the system to depressurize and cool fully before disassembling any fittings. Inspect the sight-glass tube for cracks or etching during washer replacement and replace the tube if compromised. Follow applicable local boiler codes and ASME guidelines when servicing pressurized boiler components.
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