RESILIENT-SEATED CARTRIDGE STYLE
FNW7XX
BUTTERFLY VALVE
INSTALLATION INSTRUCTIONS
FNW.COM
We reserve the right to modify or improve the designs or
specifications of our products at any time without notice.
13
1 3. TROUBLESHOOTING
Trouble
Probable Cause
Countermeasure/Remedy
Leakage
from
between
the body
and piping
flange
faces
The piping bolts are loose or they were not
tightened evenly.
After reducing the pressure, loosen the piping bolts, and then re-tighten
them by diagonal sequence. (Refer to “Piping bolt tightening procedures”)
The piping flange face is scratched or
there is waste material or other foreign
material adhering.
Remove the valve. Repair and clean the piping flange face. After
cleaning, install the valve again.
The flanges or pipes are misaligned.
Remove the valve. Align the flange/pipes and make the flanges/
pipes parallel.
The valve is misaligned.
Insert a proper gasket between the pipe flange and valve.
Torn or damaged seat.
Remove the valve body and check the seat for signs of tearing or other
damage. If any damage is observed, replace the seat with new one.
Leakage
from the
bottom
plug or
plate
The bottom plug or plate installation bolts
are loose.
Re-tighten the bottom cover installation bolts.
The valve is misaligned.
Loosen the bolts and realign the valve correctly.
Torn or damaged seat.
Remove the valve body and check the seat for signs of tearing or other
damage. If any damage observed, replace the seat.
Valve seat
leakage
Wrong material was selected for the fluid
application and the parts are corroded.
Replace the valve with one made of the proper material. For details,
please contact us regarding seat selection.
Movement of disc in the fully closed position.
Adjust the fully closed position of the disc.
The disc cannot fully close due to
insufficient output from the actuator.
Refer to the actuator selection table for correction. Check Actuator
Supplier’s Manual.
Fluid specification is not compatible with
valve specification.
Re-check the specifications.
Torsion of stem due to an unusual increase
in opening/closing torque.
Replace the valve body.
Movement of disc in fully closed position
due to loose actuator installation bolts.
Re-adjust the fully closed disc position by re-tightening the
installation bolts.
Uneven connection between seat and disc
due to unequal tightening.
Loosen the piping bolts and then re-tighten them.
Wearing and deterioration of the seat due
to long period of use or high frequency of
opening and closing operations.
Replace the seat.