In a previous post, we detailed the steps of flushing a NAIAD Stabilizer hydraulic tank off of a 100 foot Azimut yacht as part of rebuilding the entire system. The Naiad hydraulic fluid tank has a heat exchanger built inside that uses circulated sea-water to keep the hydraulic fluid cool. In this project the hydraulic fluid was turning a burnt orange color as seen in the sight glass which is an indication that the fluid was running hot. We removed the tank and removed the heat exchanger for descaling. A final critical step in the process is pressure testing the unit before it is re-installed in the tank and back in the vessel. If the unit fails it will mix sea-water with the hydraulic fluid with disastrous results.
We use a pressure testing system that starts with city water pressure and is boosted by a pump to 70 to 100 lbs. of pressure. The boosted pressure is held in place by a valve. We then monitor the pressure gauge to see if the pressure holds. If the pressure drops over an hour time then we know we have a leak.
If we detect a leak then the entire core needs to be replaced.
If no leak is detected, we proceed with the re-assembling and re-installation of the tank and add new hydraulic fluid to finish off the job.