MTS Series 505G2 SilentFlo Hydraulic Power Unit Model 505G2-30 - Manual (Page 64)

Model 505G2.20 - 505G2.30 SilentFlo™ HPU 64
Replacing the Hydraulic Fluid
Maintenance
6. If there still is any uncertainty regarding fluid quality, obtain another sample
of the fluid and have it analyzed. The fluid tests should include chemical
analysis, particle count, and viscosity checks. Most oil companies have
facilities for performing these tests, or consult MTS Systems Corporation.
7. Close the needle valve and remove the hose and valve assembly. Open the
needle valve.
Replacing the Hydraulic Fluid
Replace the hydraulic fluid in the HPU reservoir whenever you have determined
that the hydraulic fluid is no longer suitable for use.
Appearance of Hydraulic Fluid Sample
Fluid Properties Problem What to Do
Dark colored fluid Indicates chemical breakdown or
the hydraulic fluid has been allowed
to rise above the maximum
recommended temperature (severe
overheating)
Analyze the fluid and replace as
required by the analysis.
If the cause was overheating, flush the
entire system to remove varnish or
residue. Consult your MTS Field
Service Engineer to determine if
changes or adjustments to your
hydraulic system are required.
Burnt odor Indicates chemical breakdown or
the hydraulic fluid has been allowed
to rise above the maximum
recommended temperature (severe
overheating)
Analyze the fluid and replace as
required by the analysis.
If the cause was overheating, flush the
entire system to remove varnish or
residue. Consult your MTS Field
Service Engineer to determine if
changes or adjustments to your
hydraulic system are required.
Opaque fluid Indicates chemical breakdown Replace the fluid
Milky appearance Indicates water is present in the
fluid Check the heat exchanger for damage.
Look for other water sources if the
water does not appear to be coming
from the heat exchanger.
Identify and correct the source of the
water leakage and replace the fluid if
necessary.
Sediment at the bottom of
the sample container (after
sample has stood
overnight) Indicates collapsed, ruptured, or
clogged filter(s)
Analyze the fluid and replace all filter
elements.
Clean the fluid or replace it as required
by the analysis.