Installation, Operation and Maintenance Manual
Diaphragm Valves Type 15 12
(12) Inspection items
- Perform periodic maintenance. (Leakage may develop due to temperature changes or over periods of
prolonged storage, rest or operation.)
Inspect the following items.
(1) Check for any flaw, crack, or deformation on the outside.
(2) Check whether fluid leaks to the outside.
(3) Check the tightness of coupled bolt nut between the body and the bonnet and that of the
gauge cover (loose or not).
(4) Check whether the operation of the handle is smooth.
(13) Troubleshooting and action
Problem Cause Treatment
Fluid is leaking past the fully closed
The travel stop is not set correctly. Adjust the travel stop.
Solid particles have lodged in the valve. Clear the solid particles from the
Media has worn diaphragm and / or
weir. Replace.
Valve can not be fully open.
The diaphragm has pulled off the stem.
Replace diaphragm. If the valve is in
vacuum service, special vacuum
valves may be required.
Consult factory.
The metal joint failed. Remove diaphragm & compressor
and replace joint.
The handle spins freely.
The stem is broken. Disassemble bonnet and replace the
The metal joint failed. Remove diaphragm & compressor
and replace joint.
Valve leaks between body and bonnet.
Bonnet bolts have loosened. Re-tighten.
Media has crystallized on the
Disassemble and clean on a regular
basis. Replace failed diaphragm, if
The diaphragm has failed due to
fatigue. Replace.
Valve leaks from stem. The diaphragm has failed. Replace.
(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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