Gas Fitter Test 2026 – 400 Free Practice Questions to Pass the Exam

Shutting off the fuel supply is the immediate and essential action when a steam boiler burner is operating with no visible water in the gauge glass. This situation poses a significant risk of overheating and damaging the boiler, as the burner can cause the water to boil away completely without adequate fluid to absorb the heat.

When the water level drops, the temperature of the boiler's metal surfaces can rise dramatically, leading to potential catastrophic failure, such as a boiler explosion. Therefore, stopping the fuel supply ensures that the burner will not continue to operate and exacerbate the situation, providing time to address the lack of water and inspect the system safely.

While opening the water supply and notifying the building owner are necessary actions that should be taken subsequent to shutting off the fuel, they are not the immediate steps to prevent further danger. Adjusting the high-pressure limit control is also not advisable in this scenario as it does not address the immediate hazard of running the burner without water present. Thus, the primary focus must be on ensuring safety by cutting off the fuel supply first.