MTS Series 505G2 SilentFlo Hydraulic Power Unit Model 505G2-180 - Manual (Page 77)

Operating the HPU
When running the HPU, become familiar with the sounds and smells of the HPU. Changes in the sounds and
smells of the HPU might indicate that maintenance or service is needed.
About Checking the Hydraulic Fluid
Hydraulic fluid contamination and deterioration normally occur in most hydraulic systems. Failure to keep
your fluid sufficiently free of contaminants or to change the fluid before severe fluid breakdown occurs will
cause poor system performance and may lead to expensive system cleanups. Servovalves are especially
susceptible to damage from dirty hydraulic fluid.
To avoid these problems, you must maintain a clean hydraulic system. Regularly test samples of your hydraulic
fluid and follow the recommended maintenance procedures described here. For more information on hydraulic
fluid care, refer to the Hydraulic Fluid Care Guide (part number 050-000-536).
Important:
To prevent problems with inconsistent and inferior fluids, MTS recommends only Exxon Mobil DTE 25
or Shell Tellus 46 to its customers.
Check the Hydraulic Fluid
Perform the following checks of the hydraulic fluid’s condition weekly. If you suspect contamination of the
hydraulic fluid, take a sample and have it analyzed.
1. Check the fluid level on the oil level gage to verify the fluid level is correct.
• A low level can indicate a leak. If necessary, add enough fluid to bring the reservoir level up to the
proper operating level.
• A high level can indicate water contamination from the heat exchanger.
2. Check the hydraulic fluid color. Clean hydraulic fluid is amber in color.
Keep a sample of brand-new hydraulic fluid in a clean glass container for comparison. A change in color
can mean that the fluid is contaminated or that it has broken down chemically. If the hydraulic fluid appears
different than the clean sample, see the “Appearance of Hydraulic Fluid Sample” table.
3. Open the filler cap and check the smell the hydraulic fluid. Burnt-smelling hydraulic fluid can indicate a
chemical breakdown.
If you detect a distinct change in the smell of hydraulic fluid, have it chemically analyzed by the manufacturer.
4. Keep records of the maximum reservoir temperature.
High operating temperatures can cause the fluid to break down. If your records indicate a pattern of
overheating, consult your MTS Field Service Engineer to determine if changes or adjustments to your
hydraulic system are required.
Series 505G2 SilentFlo™ Hydraulic Power Unit Product Information 77
Maintenance