Table of Contents
Advertisement
Maintenance and care
Faults
Page 86 of 96
Error / Fault
Sporadic failure
Control unit without
function
(all LEDs off)
The protected devices are
switched on without pre-
purging
During pre-purging, the
purging gas valve switches
off for a short time
"Operate" LED does not
flash during purging time
01-37A2-7D0001_px_Manual_Exp-Control-Unit_20210923_0_en.docx
Possible cause
Cable break
Pressure drop / leakage
Mains voltage not
available
Device defective
Bypass activated
Incorrect purging program
activated
Excessive amounts of
purging gas are introduced
into the pressurized
enclosure
No purging gas
Purging gas valve does not
open or opens only
partially
An insufficient amount of
purging gas flows through
the Ex p enclosure
Set point pressure of the
pressure reducer is not
reached
Pressure monitor of the
control unit is
inadmissibly closed or has
a reducer
Enclosure leaks during the
pre-purging phase due to
increased internal
pressure
Ex p Control unit
Remedy
Check connections
Check tightness and leak
compensation
Check supply voltage
Return to manufacturer
Deactivate bypass
Check purging program
Reduce the purging gas
nozzle
Check purging gas valve
for the presence of supply
voltage
Check purging gas valve
for foreign particles in the
mechanical part
Increase inlet pressure to
set point value
Check purging gas nozzle
for correct value
Check set point values
"p3" and "p1" of the
control unit
Increase the cross section
of the purging gas supply
line
Purging gas supply line too
small. Enlarge cross
section of the supply line
Remove the cap or
eliminate the reduction by
taking suitable measures
Seal enclosure using
suitable measures
Check purging gas valve
for the presence of supply
voltage
APEX
px
Rev. 0
Advertisement
Table of Contents
