Troubleshooting / Fault Clearance - Gemü 625 Original Einbau- Und Montageanleitung

18 Troubleshooting / Fault clearance

Fault
Control medium escapes from
connector 4* (control function
NC) or from connector 2* (control
function NO) in the actuator
Control medium escapes from
leak detection hole*
Working medium escapes from
leak detection hole*
Valve doesn't open or doesn't
open fully
Valve leaks downstream (doesn't
close or doesn't close fully)
Valve leaks between actuator
and valve body
Valve body connection to piping
leaks
Valve body leaks
* see chapter 19 "Sectional drawing and spare parts"
625
Possible cause
Actuator piston faulty
Spindle seal leaking
Valve diaphragm faulty
Control pressure too low
(for control function NC)
Pilot valve faulty
Control medium not connected
Valve diaphragm incorrectly mounted
Actuator spring faulty
(for control function NO)
Operating pressure too high
Control pressure too low (for control
function NO and control function DA)
Foreign matter between valve
diaphragm and valve body weir
Valve body weir leaking or damaged
Valve diaphragm faulty
Actuator spring faulty
(for control function NC)
Valve diaphragm incorrectly mounted
Bolting between valve body and
actuator loose
Valve diaphragm faulty
Actuator / valve body damaged
Incorrect installation
Threaded connections loose
Sealing material faulty
Valve body faulty or corroded
34 / 40
Fault clearance
Replace actuator
Replace actuator and check control
medium for impurities
Check valve diaphragm for damage,
replace diaphragm if necessary
Operate valve with control pressure
specified in data sheet
Check and replace pilot valve
Connect control medium
Remove actuator, check diaphragm
mounting, replace if necessary
Replace actuator
Operate valve with operating pressure
specified in data sheet
Operate valve with control pressure
specified in data sheet
Remove actuator, remove foreign matter,
check valve diaphragm and valve body
weir for damage and replace if necessary
Check valve body weir for damage,
if necessary replace valve body
Check valve diaphragm for damage,
replace diaphragm if necessary
Replace actuator
Remove actuator, check diaphragm
mounting, replace if necessary
Retighten bolting between valve body
and actuator
Check valve diaphragm for damage,
replace diaphragm if necessary
Replace actuator / valve body
Check installation of valve body in piping
Tighten threaded connections
Replace sealing material
Check valve body for damage, replace
valve body if necessary