How to Change a Boiler Sight Glass

Learn how to change a boiler's sight glass.

A leaking or damaged sight glass isn’t just a maintenance issue, it can create false water level readings and introduce serious safety risks. In this episode of Boiling Point, Boiler University instructor Jude Wolf walks through the proper approach to replacing a boiler sight glass and its gaskets, including when replacement is necessary and why attention to detail matters.

We cover key warning signs, such as steam leakage, thinning glass, or buildup that won’t clear with blowdown. We also explain why sight glass replacement must be done carefully, especially when pressure is present on the boiler. This full walkthrough provides the context and precautions operators and maintenance teams need to do the job correctly.

Parts, tools, and replacement components referenced in this video are available through BoilerWAREhouse.com, where our team stocks the same components we rely on to support our own rental fleet.

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