Manual Override?

Presuming that "CCC" means "compressor capacity control," removal of the anti-surge transmitter on a running compressor could leave the compressor without any control at all, except by manual override. Without the temporary manual control, the compressor would go to either maximum capacity or minimum capacity until the transmitter is reconnected.

You should not abbreviate like CCC. You may only know what really it means? As Tornado said "Presuming that "CCC" means "compressor capacity control" may be its full form, but "Anti surge control system" is different from capacity control system. "Anti surge control system" is to protect compressor from surging due to eventual sudden reduction in discharge flow rate. "Capacity control system" is basically automatic operation of suction throttle valve OR inlet guide vanes to maintain either constant discharge pressure OR constant flow rate.

Many OEM's of centrifugal compressors do not provide manual override at all. Manual override is only useful during start-up when instrument air is not available to operate "Anti surge control system" and you are sure to line-up instrument air after starting the compressor. Manual override is not for facilitating PM or some job on anti surge transmitters by taking the loop on manual. Hope it is clear.

CCC is Compressor Controls Corporation, If I wrong correct me Jawad

You will need do manual override in order to avoid that the transmitter or transmitters included in the PM (preventive maintenance?) introduce some variance product of this activitie in the Anti-Surge Unit bringing as consequences that the Anti Surge valve´s open or change its position according the surge measured by the Anti-Surge Unit, If the Anti Surge valve open decrease it a great amount the output flow of the centrifugal compressor.

Remember that the Anti-Surge System is installed with two units, one as master and other as secondary, also it have a switch in order to select which one of this is working as main

I could recommend you that dont touch this system if you are not secure about the procedures necesary in order to work in these Anti Surge Units, this could create great problems in the Refinery or process units.

I hope this help

Regards
JP

Manual over ride is the system design facility for panel operator to put a device in over ride condition when preventive activity is need.But it is a danger condition for the compressor if this instrument is the part of safe guarding system.

If the instument mostly a transmitter when you apply the over ride and perform the job.After copmletion the atsk even the instrument is normal working condition.A remote reset is requird most of safe guarding sytem to make the logic healthy and than remover the over ride.other wise you trip your machine/plant.