Troubleshooting / Fault Clearance - GEM 490 Installation, Operating And Maintenance Instructions For The Installer And The User

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Troubleshooting / Fault clearance

Fault
Butterfl y valve doesn't
open or doesn't open fully
Butterfl y valve doesn't
close or doesn't close fully
Butterfl y valve body
connection to piping leaks
Butterfl y valve body leaks
Higher switching noise
when the butterfl y valve
opens
Possible cause
Foreign matter in the butterfl y valve
Operating pressure too high
Operator design not suitable for
operating conditions
Flange dimensions do not comply
with specifi cations
Inside diameter of piping too small
for nominal size of butterfl y valve
Control pressure too low
Operating pressure too high
Operator design not suitable for
operating conditions
Foreign matter in the butterfl y valve
Incorrect installation
Flange bolting loose
Incorrect installation
Butterfl y valve body faulty
Contamination, particles have
damaged the seat
When the disc is in the closed
position this may cause a higher
initial breakaway torque
Fault clearance
Disassemble and clean the butterfl y valve
Operate butterfl y valve with operating
pressure specifi ed in data sheet
Use operator designed for the operating
conditions
Use correct fl ange dimensions
Install butterfl y valve with suitable nominal size
Increase control pressure to the maximum
permissible pressure
Operate butterfl y valve with operating
pressure specifi ed in data sheet
Use operator designed for the operating
conditions
Disassemble and clean the butterfl y valve
Check installation of butterfl y valve body in
piping
Retighten fl ange bolts
Check installation of butterfl y valve body in
piping
Check butterfl y valve body for damage,
replace butterfl y valve if necessary
Filter upstream of valve
Operate the valve regularly
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