To ensure optimum life perform regular maintenance of the fluid and filter. Contaminated fluid is the
main cause of unit failure. Take care to maintain fluid cleanliness when servicing.
•
Check the reservoir daily for proper fluid level, the presence of water, and rancid fluid odor. Fluid
contaminated by water may appear cloudy or milky or free water may settle in the bottom of the
reservoir. Rancid odor indicates the fluid has been exposed to excessive heat. Change the fluid and
correct the problem immediately if these conditions occur.
•
Inspect vehicle for leaks daily. Change the fluid and filter per the vehicle/machine manufacturer's
recommendations or at intervals shown in the table. We recommend first fluid change at 500 hours.
Fluid and filter change interval
Reservoir type
Max oil change interval
Sealed
2000 hours
Breather
500 hours
High temperatures and pressures will result in accelerated fluid aging. More frequent fluid changes
may be required.
•
Change the fluid more frequently if it becomes contaminated with foreign matter (dirt, water, grease,
etc.) or if the fluid is subjected to temperature levels greater than the recommended maximum.
•
Dispose of used hydraulic fluid properly. Never reuse hydraulic fluid.
•
Change filters with the fluid or when the filter indicator shows it's necessary.
•
Replace all fluid lost during filter change.
C
Caution
Hydraulic fluid contains hazardous material.
Avoid contact with hydraulic fluid. Always dispose of used hydraulic fluid according to state and federal
environmental regulations.
For further information see Danfoss publication
Technical Information, Hydraulic Fluids and Lubricants
,
BC0000093.
Filtration System
To prevent premature wear, ensure only clean fluid enters the hydrostatic transmission circuit. A filter
capable of controlling the fluid cleanliness to ISO 4406 class 22/18/13 (SAE J1165) or better, under normal
operating conditions, is recommended.
These cleanliness levels can not be applied for hydraulic fluid residing in the component housing/case or
any other cavity after transport.
The filter may be located on the pump (integral) or in another location (remote). The integral filter has a
filter bypass sensor to signal the machine operator when the filter requires changing. Filtration strategies
include suction or pressure filtration.
The selection of a filter depends on a number of factors including the contaminant ingression rate, the
generation of contaminants in the system, the required fluid cleanliness, and the desired maintenance
interval. Filters are selected to meet the above requirements using rating parameters of efficiency and
capacity.
Filter efficiency can be measured with a Beta ratio (β
X
). For simple suction filtered closed circuit
transmissions and open circuit transmissions with return line filtration, a filter with a β-ratio within the
range of β
35-45
= 75 (β
10
≥ 2) or better has been found to be satisfactory.
For some open circuit systems, and closed circuits with cylinders being supplied from the same reservoir,
a considerably higher filter efficiency is recommended. This also applies to systems with gears or clutches
using a common reservoir.
For these systems, a charge pressure or return filtration system with a filter β-ratio in the range of β
15-20
=
75 (β
10
≥ 10) or better is typically required.
Service Manual
H1P 069—H1P 250 Axial Piston Single Pumps
Fluid and Filter Maintenance Recommendations
24 |
©
Danfoss | September 2020
AX152886482551en-000504
