Information; Troubleshooting / Fault Clearance - GEM 520 Installation, Operating And Maintenance Instructions

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19

Troubleshooting / Fault clearance

Fault
Control medium escapes from
vent hole (connector 4* for
control function NC / connector
2* for control function NO)
Control medium escapes from
valve spindle*
Medium escapes at union nut*
Valve doesn't open or doesn't
open fully
Valve leaks downstream (doesn't
close or doesn't close fully)
Valve leaks between actuator
flange* and valve body flange*
Valve body connection to piping leaks Incorrect installation
Valve body leaks
* see chapter 20 "Sectional drawing and spare parts"
520
18
Should there be any doubts or
misunderstandings in the preceding text,
the German version of this document is the
authoritative document!
Possible cause
Actuator membrane* leaking
Spindle seal leaking
Gland packing faulty
Control pressure too low
Control medium not connected Connect control medium
Actuator membrane* or
spindle seal leaking
Actuator spring faulty
(for control function NO)
Operating pressure too high
Foreign matter between seat
seal* and seat
Valve body leaks or is damaged Check valve body and replace if necessary
Seat seal* faulty
Actuator spring faulty
(for control function NC)
Hexagon nuts* loose
Gasket* faulty
Valve body leaks or is
corroded
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Information

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Fault clearance
Replace actuator and check control medium for
impurities
Replace actuator and check control medium for
impurities
Replace actuator
Set control pressure in accordance with data
sheet. Check pilot valve and replace if necessary
Replace actuator and check control medium for
impurities
Replace actuator
Operate valve with operating pressure specified
in data sheet
Remove actuator, remove foreign matter, check
seat seal for damage and replace if necessary
(replacement of the steel seat seal only by GEMÜ)
Check seat seal for damage and replace if
necessary (replacement of the steel seat seal
only by GEMÜ)
Replace actuator
Retighten hexagon nuts*
Check gasket and the respective sealing surfaces
for damage and replace parts if necessary
Check installation of valve body in piping
Check valve body for damage, replace valve body
if necessary