Essential Checks Before Starting Up Pneumatic Control Valves And Positioners

If you are planning to start up pneumatic control valves and positioners, you need to make sure that they are in good condition and properly set up. To avoid any malfunctions or damage, you need to perform some essential checks before the startup.

Here are five checks that you should keep in mind:

1. Flushed Pneumatic Pipes/Tubing:
   Before starting up, ensure that all the pneumatic pipes/tubing are thoroughly flushed. This will prevent any unwanted materials from obstructing the flow of air, which can result in poor performance or even failure.
2. Compressed Air Quality:
   It is essential to inspect the quality of compressed air after any maintenance activity on the compressor/line. Ensure that it is free from oil and moisture. If the supply air is contaminated, it can damage the pilot valve/torque motor and cause the positioner to malfunction or become defunct.
3. Drain Condensate:
   Drain the condensate accumulated in the condensate separator of the compressed-air pressure-regulator assembly. This will prevent any unwanted water accumulation that can cause corrosion, leading to valve malfunction or damage.
4. Check for Leakages:
   Check for leakages in the inlet and outlet pneumatic tubing and joints. There should be no air leakage from the tubing. If you notice any leakage, seal it immediately. Use a non-hardening sealant sparingly, only on the male thread of the tube fittings.
5. Adjust Required Air Supply:
   On startup, adjust the required air supply at the AFR. The supply pressure should be about 0.5 bar higher than the maximum operating pressure of the connected control actuator. This ensures that the valve operates efficiently without any pressure issues.

In conclusion, starting up pneumatic control valves and positioners requires some essential checks to ensure their optimal performance. By following these guidelines, you can avoid any malfunctions or damage, thereby saving time and money in the long run.