A butterfly valve may have jerky operation for the following reasons:
The packing is too tight
Loosen the packing torque until it is only hand tight. Tighten to
the required level and then cycle the valve. Re-tighten, if required.
CAUTION: Always follow safety instructions when operating on valve.
The shaft seals are dirty or worn out
Clean or replace components, as per assembly-disassembly procedure.
CAUTION: Always follow safety instructions when operating on valve.
The shaft is bent or warped
The shaft must be replaced. Remove valve from service and contact
Velan Field Engineering Services.
