Ex p control unit
Motor purge controller
Maintenance and repair
Rev. 0
01-37A2-7D0003_Operating instructions_MPC_20210923_0_en.docx
Page 79 of 96
The pressure monitor of
the control unit is
inadmissibly closed or
provided with a reducer.
Seal enclosure by using
suitable measures
The enclosure leaks during
the pre-purging phase due
to increased internal
pressure.
Check purging gas valve
for supply voltage
Digital flushing gas valve
does not switch to the
small nozzle after the pre-
purging phase
The temperature sensor is
connected. The internal
temperature is too high.
Check purging gas valve
for foreign particles in the
mechanical part
Wait until the internal
temperature has dropped
due to the increased flow,
or check the set
temperature switch value.
Main switch or bridge at
the terminals Hs_In /
Hs_Out is not connected.
Switch on main switch or
connect jumper to the
terminals Hs_In / Hs_Out.
Purging gas valve does not
close.
Check purging gas valve
for switched off supply
voltage.
The control unit does not
switch on the electrical
devices after the pre-
purging phase.
The pressure in the
enclosure is higher than
the switching value “p4”.
Reduce the flow rate of
the leakage air needle.
The switching value “p4”
is too low.
Check the switching value
“p4”.
The pressurised enclosure
is leaking. The switching
value is below “p1”.
Seal pressurised
enclosure.
After the purging time, the
control unit switches off
the electrical devices with
a time delay of 5 seconds.
The leakage air needle of
the digital valve is too
small.
Increase air flow rate of
leakage air needle.
The switching value “p3”
is too high.
Check switching value
“p3”.
Relay K4 or K5 do not
switch.
The switching parameter
has been incorrectly
selected.
Check switching
parameters.
The digital purging gas
valve switches on briefly
during the operating
phase.
The value “po” is too high.
Reduce the “po” value.
The pressurised enclosure
is leaking. The switching
value is below “p1”.
Seal the pressurised
enclosure.
The pressurised enclosure
is leaking. The switching
value is below “p1”.
Adjust leakage
compensation.
If the pressure drops, the
electrical devices do not
switch off.
The key switch is switched
on.
Switch off key switch.
