1、 Abnormal pressure fault

1. Unstable output pressure (large fluctuations)
   • reason：
     • Internal channels are blocked by impurities (such as fouling of valve cores and damping holes).
     • The fatigue deformation or insufficient stiffness of the spring leads to the failure of pressure regulation.
     • The back pressure at the oil drain port is too high, which affects pressure stability.
   • solution：
     • Disassemble and wash the core components of the pressure reducing valve, clean the valve core, damping hole, and filter screen.
     • Replace the spring with one that meets the specifications to ensure a matching elasticity coefficient.
     • Set up a separate oil discharge pipeline to avoid interference from back pressure.
2. No pressure output or low pressure
   • reason：
     • Reverse import and export connections (such as incorrect design of installation plates for plate valves).
     • Insufficient inlet pressure (such as upstream pump failure or pipeline blockage).
     • The valve core is stuck in the small opening position or the long damping hole is blocked.
   • solution：
     • Check the installation direction to ensure that the inlet and outlet are connected correctly.
     • Check the upstream system pressure, repair the pump or unclog the pipeline.
     • Clean the valve core and damping hole, and if necessary, grind the surface of the valve core.
3. Downstream overpressure
   • reason：
     • Rust or blockage of the needle valve assembly of the pilot valve leads to malfunction in regulation.
     • The rupture of the main valve diaphragm or the accumulation of water underneath can cause pressure loss of control.
     • The main valve spring is broken or the valve stem is stuck.
   • solution：
     • Clean or replace the needle valve assembly of the pilot valve to ensure smooth flow.
     • Replace the diaphragm and investigate the water hammer issue, clean the accumulated water below the diaphragm.
     • Replace the spring, clean the impurities on the valve stem, and check the sealing.

2、 Leakage type fault

1. The valve body and connecting parts are leaking air
   • reason：
     • Aging and damage of seals (such as O-rings and gaskets).
     • Loose connection parts (such as loose threads or poor flange sealing).
   • solution：
     • Replace corrosion-resistant and temperature resistant seals to ensure that the materials match the medium.
     • Re tighten the connecting bolts and use sealant to assist in sealing.
2. Cover air hole leakage
   • reason：
     • Poor or damaged sealing of the gasket between the cover and the main body.
     • Failure of piston seat rubber or insufficient spring strength.
   • solution：
     • Check the gasket and clean the contact surface, replace if necessary.
     • Add rubber pads or replace springs with higher strength.

3、 Functional failure type fault

1. Filter failure
   • reason：
     • The filter is clogged or damaged, causing impurities to enter the valve body.
     • The filter element is not replaced regularly, resulting in a decrease in filtration accuracy.
   • solution：
     • Clean or replace the filter screen to ensure that the filter channel is unobstructed.
     • Regularly replace the filter element according to the manufacturer's recommendations and record the maintenance cycle.
2. Valve core stuck
   • reason：
     • The gap between the valve core and the valve body is too small, or the surface is scratched during assembly.
     • Impurities in the medium get stuck between the valve core and valve seat.
   • solution：
     • Choose a reasonable clearance (such as a J-type valve clearance of 0.007-0.015mm), and grind the valve hole if necessary.
     • Disassemble and clean the valve core, inspect the surface damage and repair it.
3. Adjustment handle malfunction
   • reason：
     • Loosening or slipping of the pressure regulating screw results in the inability to fix the pressure.
     • Internal damage to the regulating device (such as worn nuts and screws).
   • solution：
     • Adjust the pressure again and tighten the screws, or replace damaged parts.
     • Repair and adjust the mechanism to ensure flexible and reliable operation.

4、 Malfunctions caused by environment and operation

1. Failure caused by environmental corrosion
   • reason：
     • Long term exposure to corrosive media such as acid mist and salt mist can corrode metal components.
   • solution：
     • Choose corrosion-resistant materials (such as stainless steel valve bodies) or install protective coatings.
     • Regularly inspect the surface of the valve body and promptly address any corrosion points.
2. Improper operation leading to malfunction
   • reason：
     • Exceeding the rated flow rate causes the main valve to oscillate.
     • Frequent start stop or sudden pressure changes can cause water hammer effects.
   • solution：
     • Select the pressure reducing valve model that matches the system flow rate.
     • Avoid severe pressure fluctuations and install stabilizing devices if necessary.

5、 Maintenance suggestions

1. regular inspectionCheck the status of seals, springs, and filters every quarter, and record pressure data.
2. Cleaning and maintenanceDisassemble and wash the valve body every six months, clean impurities, and lubricate moving parts.
3. Spare parts reserveReserve commonly used vulnerable parts (such as sealing rings and springs) to shorten the time for fault repair.
4. Professional repairComplex faults (such as membrane rupture, valve body cracks) require contacting the manufacturer or professional personnel for handling.