Viessmann VG III - Diagnostic table: Fault;behaviour of the system

28
Troubleshooting
Diagnostics (cont.)
Fault/behaviour
of the system
Flashing
code red
Cause Remedy
Burner does not
start, demand
lamp does not
illuminate
No voltage
present
Check fuse in control
unit and in plug-in
terminal block, check
electrical connections,
position of the ON/OFF
switch on control unit
and mains electrical
isolator
High limit safety
cut-out activated
Press reset button on
boiler control unit
Vitoair motor
faulty
Replace Vitoair motor
Fuse in leak
detector device
blown
Replace fuse
Fault during leak
test (fault lamp
illuminates)
Check gas pressure
nipple of gas train for
leaks.
Valves leaking, replace
gas train.
Fuse blown at
plug-in terminal
block
Replace fuse
Leak detector
device faulty
Replace leak detector
device
Burner does not
start (demand
lamp illuminates)
Gas flow pressure
too low, gas
governor cuts out
Check gas flow
pressure.
Gas flow pressure
should be at least
20Ămbar. Clean gas
filter, if necessary.
Burner control
unit faulty
Replace the burner
control units
5692Ă534ĂGB