Top 5 Common Hydraulic Power Unit Problems and How to Solve Them

Why is my hydraulic power pack overheating, and how can I prevent it?

Overheating is common and usually comes down to fluid issues, airflow or cooling problems, or the unit working harder than it should.

1. Low hydraulic fluid levels
   Low oil can allow air into the system and make the pump work harder, increasing friction and heat. Check and maintain the recommended level, top up when needed, and inspect the reservoir for leaks.
2. Poor fluid quality
   Dirt, moisture, and degraded oil reduce lubrication and heat dissipation, increasing friction. Change oil at the recommended intervals, use the correct grade, and maintain filtration to keep contaminants out.
3. Inadequate or blocked airflow
   Poor ventilation or blocked vents trap heat around the unit. Keep the power pack in a well-ventilated area, clean vents regularly, and avoid enclosed spaces where heat can build up.

If the unit is regularly overheating because it is undersized or unsuitable for the duty cycle, a replacement may be the most reliable long-term fix. Browse our hydraulic power units or contact Flowfit for help choosing the right specification.

What causes insufficient power output in a hydraulic power pack?

Low power output usually comes from air ingress, low oil, incorrect sizing, or overloading.

1. Air in the system
   Air pockets can cause cavitation and efficiency loss. Bleed the system, check suction-side connections, and ensure the reservoir is sealed correctly to prevent air intake.
2. Low hydraulic fluid levels
   Low oil reduces pressure and flow, causing weak performance. Maintain correct reservoir levels and investigate any ongoing loss of fluid.
3. Incorrect pump or motor size
   An undersized pump or motor won’t meet the required flow and pressure demands. Confirm the pack is correctly sized for the application and verify pump and motor specs match the system requirement.
4. Overloaded system
   Exceeding rated limits can reduce output and accelerate wear. Operate within the unit’s rated capacity and review load requirements.

If your current unit cannot meet the required flow or pressure, compare it against our hydraulic power unit range to find a pack that better suits the application.

Why is my hydraulic power pack operating slowly?

Slow operation is often caused by low flow, low pressure, air ingress, or worn components.

1. Air in the system
   Cavitation or aeration disrupts flow and can slow actuator response. Bleed the system and check seals or joins on the suction side.
2. Low hydraulic fluid levels
   Low oil causes pressure and flow loss, resulting in slow movement. Maintain correct fluid levels and check for leaks.
3. Worn or faulty pump
   Pump wear reduces flow and pressure capability. Inspect for wear and replace worn parts, or the pump, if performance is degraded.
4. Incorrect pressure settings
   Relief valve settings that are too low, or a faulty valve, can limit system pressure. Verify settings and replace or repair faulty valves.

Where slow operation is caused by an undersized or worn-out unit, replacing the pack can restore performance and reduce downtime. View our hydraulic power packs to compare options.

Why is my hydraulic power pack making excessive noise and vibrating?

Noise and vibration are often linked to air or cavitation, poor suction conditions, loose components, or incorrect sizing.

1. Air in the system
   Cavitation causes noise, vibration, and premature wear. Bleed the system and ensure it’s properly sealed.
2. Low hydraulic fluid levels
   Low oil can cause the pump to draw air, increasing noise and vibration. Top up and inspect for leaks.
3. Loose or misaligned components
   Loose pump or motor mounts, fittings, or misalignment can create vibration. Tighten, realign, and replace worn mounts or fittings if needed.
4. Overloaded system
   Excess load strains components and increases noise. Operate within rated capacity and confirm correct sizing.

Persistent noise and vibration can lead to premature pump, motor, and component failure. If the unit is no longer suitable for the application, browse our hydraulic power units or speak to our team for help with sizing.

Why is my hydraulic power pack not generating enough pressure?

Low pressure can come from priming issues, suction leaks, internal leakage, or relief valve problems.

1. Gear pump not priming
   Ensure the suction filter is fully submerged in oil.
   • Double-Acting (D/A): Remove the relief valve and run the pump briefly until fluid exits the port, then refit the relief valve.
   • Single-Acting (S/A): Follow the same process, but remove the check valve instead.
2. Loose inlet connection on the gear pump
   Inspect and tighten suction-side fittings or hoses. Even small air leaks can prevent pressure build-up.
3. Damaged O-rings on relief or directional valves
   Directional valve leaks may show external oil loss, but relief valve O-ring issues can be internal and harder to spot. Inspect seals and replace if worn.
4. Pressure relief valve fault
   A broken spring or contamination can wedge the pressure relief valve open, dumping flow back to tank. Clean or inspect the valve and replace if needed.

If pressure loss continues after checking priming, suction connections, seals, and the relief valve, the unit may need repair or replacement. You can browse our hydraulic power units or contact Flowfit for advice.

General prevention tips

By keeping your hydraulic power pack well-maintained and operating under optimal conditions, you can minimise overheating risk, reduce downtime, and extend the lifespan of the unit.