May.20,2026
Relief valves are installed at the upper and lower ends of the main control valve to set the maximum system pressure. They may produce noise for the following reasons:
Air mixed in oil causes cavitation in the pilot chamber, resulting in high-frequency noise. Bleed air completely and prevent re-entry.
Pilot valve spring fatigue or deformation causes unstable pressure regulation and fluctuation noise. Replace the spring.
Needle valve wear from frequent operation prevents tight sealing, causing unstable flow and pressure fluctuation noise. Repair or replace the needle valve.
