dinil

: Make sure that u put your controller in manual and check, if your valve does not hunt then need to tune control loop.

If u put your controller in manual mode and valve hunting remains then
1) check air pressure setting through AFR. w.r.t to actuator requirement
2) Check any leakage in air tubings /pipings or from actuators
3) provide lubricating and greacing on stem
make sure your gland packing is not providing friction to stem, loose gland follower nut (slightly).

thank u so much amshah