Viessmann Vitocrossal 300 Service Instructions For Contractors page 13

Further details regarding the individual steps
yes
Ignition
yes
Gas train opens
yes
Ionisation current
builds
Symbol A
yes
Burner in opera-
tion
no Fault EE
no Fault EE
no Fault EE
no Stops below the
set boiler water
temperature and
restarts immedi-
ately
Commissioning, inspection, maintenance
(cont.)
Check the ignition
module (control
voltage 230 V
across plugs
"X2.1" and "X2.2")
Check the gas train
(control voltage
230 V); check the
gas supply pres-
sure
Check the ionisa-
tion electrode
adjustment and the
gas line for air-
locks
Check the flue gas
system for tight-
ness (flue gas
recirculation),
check the gas flow
pressure
13