五.Noise, Overheating, and Pump Failure Issues
1.Figuring out the source of noise: mechanical or hydraulic.
If you hear a sound like metal hammering, it probably means air has gotten into the hydraulic fluid. Turn off the pump immediately and check if the oil level in the tank is where it should be. Look for air in the oil (for example, make sure the return pipe is submerged below the oil level, or that the return flow isn't too fast, which can suck air into the tank). Also, check if the suction pipe is sealed properly and if the pipe size is correct. The suction flow rate should usually be under 0.8 m/s. If there's a filter on the suction port, you can remove it to test.
2.When the pump overheats:
If the pump's overheating and you notice the heat is mostly around the front bearing, it usually means the bearing is damaged. Normally, the pump housing temperature should be 10-15°C higher than the oil tank. If it's higher than that, it could mean the pump is leaking too much. Check the pump's outlet filter and the system's return oil filter. If you find copper shavings, that's a sign the pump's been worn out. You should also check for external leakage, especially from the T-port under working pressure (e.g., 200 bar).
Types of pump leakage:
Internal leakage: This is when oil leaks from the pressurized area to the suction area between the oil distribution plate and the pump housing. It's hard to measure.
External leakage: This happens when oil leaks from the pump's internal parts to the outside of the housing, which is more concerning.
In general, a leakage rate up to 10% of the pump's rated flow is acceptable. If it's more than that, the pump should be repaired.
