1、 Daily inspection (daily/shift)

1. Appearance and operational status inspection
   • Valve body leakageObserve whether there is any medium leakage at the valve body connection (such as flange, threaded interface). If a leakage is found, immediately stop the machine and tighten the bolts or replace the sealing gasket.
   • Actuator exceptionCheck if there is any abnormal noise, overheating or vibration in the electric actuator (such as motor, gearbox). If the temperature exceeds 65 ℃, stop the machine for cooling.
   • Environmental interferenceConfirm that there are no strong electromagnetic fields (such as frequency converters, high-power motors) or corrosive gases around the valve to avoid signal interference or component corrosion.
2. Monitoring of operating parameters
   • Through HMI or upper computerCheck the deviation between the valve opening, flow/pressure setting value and the actual value (error should be ≤± 1%). If the deviation continues to increase, calibrate or replace the sensor.
   • Record operational dataRecord the number of valve actions and the frequency of opening changes to provide a basis for adjusting maintenance cycles in the future (such as shortening maintenance intervals for high-frequency action valves).

2、 Regular maintenance (weekly/monthly)

1. Cleaning and lubrication of mechanical components
   • Valve stem cleaning：
     • Turn off the medium supply, remove the valve cover, and wipe the surface of the valve stem with a dust-free cloth to remove oil stains and impurities.
     • If the valve stem has scratches or wear, it needs to be polished with fine sandpaper (≥ 1000 mesh) and then coated with special lubricating grease (such as Molykote DX).
   • Actuator lubrication：
     • Add lubricating oil (such as ISO VG 32 hydraulic oil) to the gearbox or transmission components, and the oil level should be between the oil level markings.
     • Avoid using lubricating grease containing graphite or molybdenum disulfide to prevent dust pollution of electronic components.
2. Electrical system inspection
   • Tightening of wiring：
     • Disconnect the power supply and check if the actuator wiring terminals and sensor plugs are loose or oxidized (such as discoloration of the terminals).
     • Tighten the terminals with a torque wrench (refer to the instruction manual for torque values, usually 0.5-1.0 N · m).
   • insulation test：
     • Use a 500 V megohmmeter to measure the insulation resistance between the motor winding and the casing. The resistance value should be ≥ 1 M Ω (if it is lower than 0.5 M Ω, the motor needs to be dried or replaced).
   • Grounding inspection：
     • Confirm that the grounding wire (yellow green dual color wire) of the actuator housing is reliably connected, and the grounding resistance is ≤ 4 Ω (measured with a grounding resistance tester).
3. Control function testing
   • Manual/Automatic Switching：
     • Switch to manual mode through HMI or local control panel, manually control the valve opening (such as from 0% to 100%), and observe whether the action is smooth and without jamming.
     • Switch back to automatic mode, input an analog signal (such as 4-20 mA), and verify whether the valve opening is linearly related to the signal (with an error of ≤± 0.5%).
   • Emergency stop function：
     • Trigger the emergency stop button, confirm that the valve can stop operating within 2 seconds and maintain its current position, reset and restore normal function.

3、 Deep maintenance (every 6 months/year)

1. Maintenance and replacement of valve internals
   • Valve core/seat inspection：
     • Disassemble the valve body and inspect the sealing surfaces of the valve core and seat for wear, corrosion, or scaling (such as hard particle scratches).
     • If the damage depth of the sealing surface is greater than 0.1 mm, the valve core/seat needs to be replaced (it is recommended to use original accessories, such as Burkert 8000 series valve internals).
   • Sealing ring replacement：
     • Replace the valve stem sealing ring (such as O-ring, V-ring), and ensure that the material is compatible with the medium (such as PTFE for acid and alkali resistance and fluororubber for high temperature resistance).
     • After replacement, an air tightness test is required (fill with 0.6 MPa gas and maintain pressure for 5 minutes without leakage).
2. Calibration of actuators and firmware upgrade
   • Position sensor calibration：
     • Connect the actuator through Burkert specialized software (such as EDIP Configurator), enter the "Calibration" menu, and follow the prompts to complete zero point (0%) and full-scale (100%) calibration.
     • After calibration, a full stroke test is required to ensure that the opening feedback signal is consistent with the actual position.
   • Firmware update：
     • Visit Burkert to download the latest firmware version, update the actuator firmware using software upgrade tools such as USB to RS485 adapters, fix known vulnerabilities, and optimize control algorithms.
3. Channel cleaning (applicable to media containing impurities)
   • chemical cleaning：
     • If the medium contains oil or organic matter, soak the inside of the valve body in a 5% sodium hydroxide solution for 2-4 hours, and then rinse with clean water.
   • Mechanical cleaning：
     • For hard particle sedimentation (such as sand particles), high-pressure water guns (pressure ≤ 10 MPa) can be used to flush the flow channel, avoiding the use of sharp tools to scrape the inner wall.

4、 Fault handling and prevention

1. Common faults and solutions

   Fault phenomenon	Possible reasons	solution
   Valve does not operate	Power failure, motor damage, signal interruption	Check the power supply voltage (24 V DC ± 10%), replace the motor, rewire and test the signal transmission (such as measuring the 4-20 mA signal with a multimeter)
   Large fluctuations in opening degree	Position sensor malfunction, PID parameter mismatch	Calibrate the position sensor and adjust the PID parameters through software (such as increasing the integration time Ti to 10-20 seconds)
   Leakage exceeds the standard	Aging of sealing ring and wear of valve internals	Replace the sealing ring, grind or replace the valve core/seat (ensuring surface roughness Ra ≤ 0.4 μ m)

2. Preventive maintenance recommendations

   • Establish and maintain archivesRecord the maintenance time, replacement of component models, and changes in operating parameters, and analyze the trend of faults (such as counting the number of leaks every 3 months).
   • Spare parts inventory managementReserve commonly used vulnerable parts (such as sealing rings, valve cores, motors) to ensure that the inventory meets the requirement for one complete maintenance (usually it is recommended to reserve 5% to 10% of the valve quantity corresponding to spare parts).
   • Operator trainingRegularly provide training on Burkert 2702 structural principles, calibration methods, and fault diagnosis to maintenance personnel (such as conducting an annual practical assessment).

5、 Long term disuse protection

1. Short term suspension (1 week to 1 month)
   • Keep the valve in a semi open position (40%~60% opening) to avoid long-term compression deformation of the valve core/seat.
   • Manually operate the valve 1-2 times a week to prevent mechanical components from getting stuck.
2. Long term discontinuation (>1 month)
   • Drain the medium inside the valve body and blow the flow channel with dry nitrogen gas (pressure 0.1-0.2 MPa) to prevent corrosion.
   • Apply anti rust oil (such as WD-40) on the actuator motor shaft, wrap the valve body and actuator with plastic film, and store in a dry environment (humidity<60%).