Depressurise pressure accumulator

This function is used to depressurise the pressure accumulator.
Note:
The oil level in the compensation tank must be below the MAX marking, otherwise there is a risk that the compensation tank will rupture.
Test conditions:
Procedure:
  1. Start the function.
  2. Check conditions.
  3. Check that the oil level in the compensation tank is below the MAX marking.
  4. Wait until the function has been completed.
  5. Function complete.