What would happen if the pressure in the boiler exceeds 900 PSI?

When the pressure in a boiler exceeds 900 PSI, the Boiler Safety Valve is designed to open and relieve excess pressure to prevent dangerous conditions. This safety feature is crucial in maintaining the integrity of the boiler and ensuring safe operation. If pressure increases beyond the set threshold, the safety valve activates, allowing steam to escape until pressure is reduced to a safe level. This operation helps prevent boiler explosions or other serious hazards that could arise from over-pressurization.

The Boiler Safety Valve is a fundamental safety mechanism in steam systems, and its design ensures that it reacts to pressure increases automatically, without requiring manual intervention. By relieving pressure, it protects the entire system from potentially catastrophic failures.

The other options do not appropriately address the situation of excessive pressure in the boiler. Shutting off the steam flow or decreasing heat would not directly relieve pressure, and the potential for water overflow is unrelated to the operation of the boiler safety mechanisms in place.