Viessmann VITOCROSSAL 200 Service Instructions Manual page 44

Troubleshooting
Diagnosis
(cont.)
Fault Display
code *1
F A7 F A7
F A7 F A7
F A7 F A7
F A7 F A7
F A8 F A8
F A8 F A8
All fault codes are saved to the fault memory and the last 10 can be called up.
*1
44
System charac-
teristics
No flame signal
during safety time;
ionisation flame
monitor reports no
flame signal
No flame signal
during safety time;
ionisation flame
monitor reports no
flame signal
No flame signal
during safety time;
ionisation flame
monitor reports no
flame signal
I Danger
Plug-in termi-
nals on the
burner con-
trol unit 'live'.
Check con-
nections "L
1", "N" and
earth con-
ductor.
No flame signal
during safety time;
ionisation flame
monitor reports no
flame signal
Flame extin-
guishes during
operation
Flame extin-
guishes during
operation
Cause
Incorrect gas type
selected
Gas train does not
open
Connections "L1"
and "N" at the
power supply ter-
minals of the con-
trol unit or burner
control unit inter-
changed
Combustion char-
acteristics not
ideal
Incorrect gas type
selected
Burner gauze
assembly faulty
Measure
Adjust gas type
(see page 11)
Check gas train
and replace if
required
Check core alloca-
tions and alter if
required
Adjust burner (see
from page 14)
Adjust gas type
(see page 11)
Replace burner
gauze assembly if
wire gauze dam-
aged