Installation, Operation and Maintenance Manual
Butterfly Valves Type 56, 75, 56D, 75D 18
(12) Inspection items
- Perform periodic maintenance. (Leakage may develop due to temperature changes or over periods
of prolonged storage, rest or operation.)
(1) Check for flaw, crack, or deformation on the valve.
(2) Check for leaks to the outside.
(3) Check for the deformation of seat due to improper installation of valve.
(4) Check for the smoothness of handle operation.
(13) Troubleshooting
Phenomenon Cause Treatment
Fluid is not stopped in
the full closed position
at the seat.
1) The stopper is not set correctly.
2) The seat is damaged or worn.
3) Foreign materials are caught.
4) The disc is damaged or worn.
5) The connecting bolts are over tightened or
tightened unevenly.
Adjust the stopper.
Replace the seat.
Clean up.
Replace the disc.
Adjust and retighten.
Fluid leaks to the
1) The seat is damaged or worn.
2) The connecting bolts are not tightened in
proper torque or evenly.
Replace the seat.
Adjust and retighten.
The handle does not
work smoothly
1) Foreign materials have adhered.
2) The gearbox is damaged.
3) The connecting bolt is over tightened.
Adjust and retighten.
Replace the gearbox.
Adjust and retighten.
Valve does not operate
1) The gearbox is damaged
2) The stem is damaged.
3)The spring pin is damaged
Repair or replace.
Replace the stem.
Replace the spring pin
(14) 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.)
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