Hydraulic Power Unit Maintenance Checklist: A Guide for Industry Professionals

Proper maintenance of your Hydraulic Power Unit (HPU) is crucial to ensure its longevity and optimal performance. While specific maintenance schedules may vary depending on operating conditions, the following guidelines provide a general framework for daily, weekly, quarterly, and annual maintenance tasks to keep your power unit operating at its best.

Daily Maintenance Tasks

Visual Inspection:

•  Check for leaks in hoses, fittings, and seals. Some parts may need to be wiped clean to conduct a proper inspection.

○  If you find any loose connections, pause operation, and tighten the fitting to secure (but be sure not to over-tighten).
○  Replace fittings if the connection continues to leak after tightening.
○  If fitting uses a soft seal, replacing seal may be enough to stop connection from leaking.

•  Replace hoses if there is visible fluid seepage or dampness around the crimp area, particularly where the hose cover meets the fitting (this is a sign that there is a leak between the inner tube and the outer cover of the hose), or if there is damage to the hose cover.
•  Inspect and empty drip pans.
•  Look for signs of damage or wear on components. If you find damage, assess if any parts need replaced and take measures to prevent further harm.
•  Clean any spills or leaks promptly.
•  Inspect cylinders for damage and ensure smooth piston rod movement.
•  Tighten bolts on pumps, electric motors, valves, etc.
•  Verify pressure gauge readings.

Temperature Checks:

•  Check your oil temperature. In most cases, 120° F (49º C) at the reservoir is considered an ideal operating temperature, though some systems are designed to operate at 130° F (54º C) or higher. If you don’t know the maximum operating temperature or viscosity limitations for your equipment, check your component manual. Be sure to take oil temperature readings at the reservoir, not from a component or along the piping.
•  Check for excessive heat buildup in components.

Assess Oil:

•  Monitor oil levels in the reservoir. Low fluid levels can cause the pump to draw in air, damaging components. Replace the oil when necessary, following manufacturer's recommendations. (See Reservoir Cleaning instructions in Annual Tasks.)
•  Visually inspect oil for contaminants like water or debris.

Operational Checks:

•  Test hydraulic functions to ensure proper operation. Listen for unusual noises from the pump or motor as this may be a sign that equipment is not running properly.
•  Maintain detailed maintenance records to track service history and identify potential issues. Document all maintenance tasks, including dates, technician names, and any parts replaced. Record any problems you encounter to ensure other operators are aware of issues.
 

Monthly Maintenance Tasks

Filter Inspection:

•  Check the condition of hydraulic filters and replace them if necessary.

○  If filters do not have a contamination indicator, be sure to log the installation date in your records, as well as a recommended replacement date. Replacement intervals will depend on the operating conditions, and regular oil analysis can help to determine an appropriate replacement interval. (See Oil Analysis below for more information.)

•  Inspect and clean pump inlet strainers if you observe signs of oil starvation. Suction strainers, especially when used as the sole filter, are prone to clogging. Systems with additional filtration are less susceptible to strainer blockage. While modern, properly filtered systems rarely experience clogged strainers, sudden contamination from heavy varnish or a failed return filter element can cause rapid blockage.
•  If the HPU has a water-cooled oil cooler, remove and inspect the strainers in the water pipe, cleaning thoroughly if needed.
•  If the HPU has an air-cooled cooler, turn off the cooling fan and use compressed air to remove debris, making sure to blow in a direction that will not push debris back into the system.

Thorough Cleaning:

•  Clean the HPU and surrounding area to remove dirt and debris.
•  If you work in a space with significant buildup of dirt and debris, cleaning on a more frequent basis is recommended for best results.
 

Quarterly Maintenance Tasks

Oil Analysis:

•  Triad Technologies offers an oil sampling kit, which can be used to determine the condition of the fluid. A laboratory analysis provides particulate contamination levels including wear metals, water/moisture, and other contaminants. The test will also determine if there is any additive depletion.
•  Replace the oil when necessary, following manufacturer's recommendations. (See Reservoir Cleaning instructions in Annual Tasks.)

Accumulators (If Applicable):

•  Check nitrogen pre-charge pressure to ensure they are within the recommended limits. Note that hydraulic pressure in accumulator must be at zero to measure proper pre-charge pressure. 

Operational Checks:

•  Review service book/records for any recurring issues to determine if additional maintenance or a more permanent solution is required for any problems. Carry out any additional requested maintenance tasks.
•  Check the maintenance schedule of all parts to ensure parts are being replaced as recommended by the manufacturer.
 

Annual Maintenance Tasks

Reservoir Cleaning:

•  Drain the reservoir of your power unit and clean the interior thoroughly.

○  If reusing the oil, be sure to drain it into clean containers and seal them for temporary storage.
○  Check for sediment buildup, rust, or sludge inside the reservoir.
○  Do not use cotton towel for cleaning.
○  Only use cleaning solutions recommended by your oil supplier.
○  Be sure to seal reservoir tanks if they are not being immediately refilled.

•  Flush the hydraulic system to remove any contaminants.
•  Filter the oil through a separate filter unit before refilling the clean tanks. Triad Technologies offers portable filter carts for filtering used oil, or for adding new oil to the reservoir, as new oil is not as clean as hydraulic systems require.

Component Inspection:

•  Check the condition of pumps, motors, valves, and other components.
•  Replace worn or damaged parts.
•  Calibrate pressure gauges and transducers.

Functional Testing:

•  Perform a comprehensive system test to verify performance.
•  Adjust system settings as needed.
 

OEM Recommendations

Always refer to the specific maintenance guidelines provided by the original equipment manufacturer (OEM) for your power unit. For HPUs engineered by Triad Technologies, customers can contact us for recommended service intervals and procedures for their specific applications and parts.

By following this recommended maintenance schedule and adhering to OEM guidelines, you can significantly extend the life of your HPU and minimize downtime! Find replacement parts and other accessories for you HPU by visiting Triad’s Hydraulic Power Unit Accessories page. You can also contact us directly for questions about your unique system.