Installation, Operation and Maintenance Manual
H-A003-E-15 Ball Valve Type 21・21α Pneumatic Actuated Type AA 30
Problem Cause Treatment
The valve does not operate by
Foreign matter is in the valve. Disassemble the valve to remove
foreign matter. (Refer to page 28)
The torque of the valve is increased by the
piping stress. Remove the piping stress.
The torque is increased by the influence
(temperature, components, pressure) of fluid
on the valve.
Check service condition.
(Refer to page 5)
Fluid leaks from the valve
even when the valve is closed
The carrier is loosened.
Adjust the face pressure between the
ball and the seat.
(Refer to page 27)
The seat is worn. Replace the seat with a new one.
The seat and ball are scratched. Replace the scratched seat and ball
with new ones.
Foreign matter is in the valve.
Discharge the foreign matter from the
valve by opening and closing the valve
Fluid leaks from the valve.
The union nut is loosened. Tighten up the union nut.
The O-ring is scratched or worm.
Replace the O-ring with a new one.
The O-ring is projected from the groove.
The sliding face or the fixed face of the
O-ring is scratched or worm.
Replace the sliding face or the fixed
face with a new one.
The actuator operates, but the
valve is not open or close.
The stem or the joint is broken. Replace the stem or the joint with a
The engagement between the stem and
the ball is broken.
Replace the engagement with a new
(23) Handling of residual and waste materials
- Make sure to consult a waste treatment dealer for recommendations on the proper disposal of plastic
valves. (Poisonous gas is generated when the valve is burned improperly.)