What does a steam pressure gauge indicate?

A steam pressure gauge specifically measures the pressure of steam within a boiler system. This pressure is a critical parameter because it indicates how much force the steam can exert, which directly impacts the efficiency and performance of the boiler and any connected steam systems. Understanding the pressure is essential for safe operation, ensuring the system operates within its designed specifications to avoid potential hazards like overpressure situations that could lead to boiler failure.

The other options do not relate to what a steam pressure gauge measures. Ambient temperature is concerned with the surrounding environment's temperature, the amount of water in the boiler is typically monitored by a water level gauge, and electrical conductivity pertains to the ability of a substance to conduct electricity, which is unrelated to steam pressure. Thus, the correct answer reflects the specific function of the steam pressure gauge in monitoring system operations.