What should be done immediately when a steady white stream is emitted from the fixed maximum liquid level gauge?

When a steady white stream is emitted from the fixed maximum liquid level gauge, it indicates that the liquid propane is being overfilled and is being vented through the gauge. This can pose serious safety hazards, including the risk of fire or explosion, as well as the potential for environmental harm.

Closing the hose end valve is the correct action to take immediately in this situation. By doing so, you can stop the flow of liquid propane from the tank or cylinder, mitigating the risk of further spillage and allowing for a safer environment. This step is essential to prevent more propane from escaping and to maintain safety during the filling or dispensing process.

In contrast, increasing pressure, replacing the gauge, or turning off the cylinder would not directly address the immediate danger posed by the overfilling situation and the resulting venting from the gauge. Instead, it is crucial to act quickly and close the hose end valve to ensure safety and prevent further incidents.