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How to Get Water Out of a Hydraulic System

Water in hydraulic oil is bad once it exceeds a certain level. If the fluid looks cloudy or milky, it means water has contaminated the hydraulic fluid and it needs to be replaced. Water can cause all sorts of operational problems, including:

  • Reduces lubrication efficiency
  • Causes the system to run hotter than normal
  • Increases the risks of cavitation
  • Reduces the system’s ability to convert mechanical power into fluid power and vice versa
  • Reduces the efficiency of filters
  • Creates sludge that can clog lines and filters
removing water of a hydraulic system
There are several different methods you can use to attempt to remove water from the hydraulic oil.  However, they require specific equipment and tools, such as gravity separation, spinning the fluid in a centrifuge, filtering, and water-absorbent filter elements and/or air breathers.
Regardless of the method used, you will need to drain the fluid from the system first. Next, a complete flush of the system is required to ensure all water and emulsified oil has been removed. Often, it is easier just to drain and flush the system, after identifying how the water got into it, and then to fix that problem.

How to Flush Water from a Hydraulic System

  1. Drain the oil from the system.
  2. Clean out the reservoir and remove all deposits and sludge.
  3. Replace the filters. 
  4. Flush the system with a lower viscosity oil.
  5. Bring the oil to operating temperature and shut the system down.
  6. Drain the hot flushing oil from the system.
  7. Flush the system a second time.
  8. Replace the filters.
  9. Fill the system with the correct hydraulic fluid about 75% full.
  10. Run the system to circulate the new fluid using the appropriate methods.
  11. Check the oil level and refill to the correct level.
  12. Operate the system for at least six to eight hours.
  13. Check the oil for signs of water.
  14. If there is no water present in the fluid, replace the filters.
hydraulics piston
After flushing the system, if water returns, you will need to pinpoint the cause. Is there a leak somewhere in the system allowing water to get into the fluid? For instance, there could be a cracked gasket. Could there be damp air being drawn into the tank that is condensing on the internal surfaces?
Removing water from a hydraulic system is not difficult. However, if you do not perform regular maintenance checks, the longer it is in the system, the more damage it can cause. So, regular maintenance is vital to identify water in the hydraulic oil sooner rather than later.
For hydraulic system pumps, motors, cylinders, and other related parts and components, please feel free to contact White House Products, Ltd. at +44 (0) 1475 742500 today!

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