How should you check the air charge in a hydraulic accumulator?

To accurately check the air charge in a hydraulic accumulator, it is essential to first reduce all hydraulic pressure within the system. This is because the accumulator typically has a pre-charged air zone separated from the hydraulic fluid, and the air charge pressure must be assessed without the influence of hydraulic pressure.

When hydraulic pressure is present, it can lead to misleading readings because the compressed fluid can exert additional pressure on the air side of the accumulator. Therefore, observing the reading after completely relieving the hydraulic pressure ensures that you are measuring just the pressure of the air charge, providing a true representation of its state.

Measuring while hydraulic pressure is present can lead to inaccurate diagnostics, potentially leading to improper maintenance or operation decisions. Hence, the best practice is to ensure that the accumulator is isolated from hydraulic pressure before performing the air charge check.