Georg Fischer DIASTAR SIX Manuel D'utilisation D'origine page 46

7. Help in case of problems
Please observe the safety information when handling defects!
In case of other malfunctions or further questions please contact your Georg Fischer
representative!
Malfunction type
Deformation and expansion of piping / valve
Premature wear of diaphragm valve or indi-
vidual parts
Leakage to the outside at flange joint
Leakage to the outside at union nuts
Leakage between valve body and housing
nut connection
Leakage at seat
Sluggish valve
Leakage of control medium on the non con-
nected air connections
Valve does not perform specified stroke or
even does not close or open
Leakage of medium at the indicator pin
Leakage of medium at the indicator pin
Premature wear of diaphragm
Actuator does not switch – marks of icing
on the valve
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Measures to be taken
Piping stresses, especially those resulting from restricted ther-
mal expansion, can be the cause of the malfunction. Improve the
piping support
After dismounting, if you determine that the material of the
housing or the seal is inadequately resistant.Choose suitable
materials from the list of "Chemical Resistance" in the Planning
Fundamentals or contact your +GF+ representation
Tighten joint or if necessary replace sealings
Tighten joint with manual effort or if necessary change sealings
Screw housing nut tight, till...
... a uniform all-around gap of 0.5 up to 1 mm between valve body
and bonnet is achieved and
... the half-round position indicator aligns with the friction lock or
if necessary, replace diaphragm in accordance with the chapter
"Replacing diaphragm"
Replace diaphragm in accordance with the chapter "Procedure -
Replacing diaphragm"
• Check spindle for wear and if necessary grease the spindle
• If necessary replace seals and other functional parts
Replace sealings on the spindle and piston
• Check control pressure
• Check connections and suitable mode of function (FC, FO, DA)
• Check function of aeration and deaeration line
Replace sealings on the spindle and piston. Replace diaphragm
Replace sealings on the spindle and piston
• Check control pressure
• Check connections and suitable mode of function (FC, FO, DA)
• Check size of actuator
• If necessary reduce number of spings sets (FC mode)
• Check and clean if necessary deaeration drill on the interme­
diate piece
• Check chemical and mechanical resistance of the used dia-
phragm. More information can be found in further chapters of
the Planning Fundamentals
Condensate is freezing
• Dry control air
• Seal indicator cap with a foamed rubber sealing