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How to Troubleshoot a Valve

Hydraulic Valves are used to control the flow of fluids in high-pressure lifting systems. When pressure is required to lift a hydraulic cylinder, the valve regulates the flow of oil through a series of electromagnetically operated spools. Hydraulic valves are usually maintained at regular service intervals, but occasionally, high levels of usage can cause them to fail. By following a troubleshooting checklist, a number of simple repairs can be made so the machinery can be returned to normal service.

Hydraulic Pressure Control Valves


    Low Pressure

  1. 1

    Always refer to the technical data manual whenever symptoms of low pressure appear. Establish the correct pressure for the system you are working on and adjust the pressure control gauge to the recommended setting. Observe for 15 minutes; if the system is capable of holding pressure, no further action is required.

  2. 2

    Relieve all pressure from the system if continued drops are present. Use a hexagonal key to remove the front block from the hydraulic valve. Pull out the spools and place them on a flat working surface. Check for signs of dirt, worn seals, damaged springs or obstructions in the seats of the valve. Replace any damaged parts and wipe out the chambers of the valve with a clean piece of cloth.

  3. 3

    Reassemble the valve, even if the components appear to be in good working order. Occasionally, the pressure within the system can cause spools to dislodge. Take care to ensure all of the components are put in accurately. Reapply pressure to the system to see if the problem has been solved. If lack of pressure persists, the problem is likely to rest with the hydraulic hoses or cylinder.

    Excessive Noise

  4. 1

    Run a hydraulic system several times to locate where the noise is coming from. Often, isolating the noise will indicate where the problem is. Relieve the system of pressure and remove the front block of the valve with a hexagonal key and check for signs of wear in the seat or poppet, as this can cause the spools to dislodge. A damaged seat or poppet will require a full valve replacement.

  5. 2

    Run the hydraulic system again and monitor variations in pressure to see if they fall within the recommended range. Often, an excessive return of oil to the tank can cause the valve to rattle. Adjust the flow of oil by inserting a hexagonal key into the relevant grub screw and turn inward to reduce oil flow. If this does not solve the problem, it may be necessary to change the hydraulic hoses with alternatives of a larger diameter.

  6. 3

    Check the quality of the oil with an oil viscosity testing kit. If the oil is running too thick, excessive pressure is placed on the valve and this can cause the components inside to shudder lightly while the system is in use. Although this problem is not a direct fault of the valve itself, use a thinner grade of oil to ensure efficient system operation.


Ningbo Hanshang Hydraulic Co.,Ltd
Sales Manager:zhou shan jian    Tel:+86-574-86361966   Fax:+86-574-86361266   Email:sales@hshydraulic.com