What method allows you to determine the air pressure charge in an accumulator when the engine is inoperative?

To determine the air pressure charge in an accumulator when the engine is not in operation, observing the pressure at which a rapid drop begins during operation is the most effective method. When the system is operating, and you notice a sudden drop in pressure, it can indicate the point at which the accumulator is reaching its charge limit. This is crucial because accumulators are designed to maintain pressure and deliver hydraulic fluid as needed; if the pressure drops sharply, it implies that the accumulator might be reaching its low-pressure threshold.

This method effectively reveals the working pressure of the accumulator under load. By evaluating the conditions under which the pressure begins to decline rapidly, operators can infer the appropriate air pressure charge needed to maintain optimal accumulator performance.

The other methods either do not provide the necessary data or relate more to operational parameters rather than directly indicating the air charge. For example, measuring fluid temperature does not correlate with air pressure, and checking the manual settings can provide theoretical values but lacks real-time, practical application. Activating hydraulic units simultaneously might reveal some operational characteristics of the system but won't give specific insight into the air charge of the accumulator without noting the pressure behavior during that activation.