Viessmann Vitodens 222-F Installation And Service Instructions For Contractors page 93

Fault codes
(cont.)
Fault code dis- System characteristics
played
85 Burner in a fault state
95 Burner blocked
The burner starts again once
the CO level is below the
CO limit.
96 Burner in a fault state
A3 Burner blocked
A7 Control mode as per deliv-
ered condition
A8 Burner blocked. The venting
program is started automati-
cally (see page 137)
A9 If a heating circuit with mixer
is connected, the burner op-
erates at its lower heating
output.
If only one heating circuit
without mixer is connected,
the burner is blocked.
B0 Burner in a fault state
B1 Control mode as per deliv-
ered condition
B4 Controls as if the outside
temperature were 0 °C
B5 Control mode as per deliv-
ered condition
Cause
Gas supply insufficient
during calibration
CO limit exceeded
CO limiter sensor fault
Flue gas temperature sen-
sor incorrectly positioned
Programming unit faulty
Air in the internal circula-
tion pump or minimum
flow rate not achieved
Internal circulation pump
blocked
Short circuit, flue gas tem-
perature sensor
Communication error, pro-
gramming unit
Internal fault
Internal fault
Troubleshooting
Measures
Test static gas pressure and gas
flow pressure.
Check that on-site gas line and gas
flow switch are correctly sized.
Visually inspect gas train inlet and
strainer on the inlet side for con-
tamination.
Note
Contamination from a brazed gas
line, for example, can block up the
gas train strainer on the inlet side.
Press reset button R.
Danger
An increased concentration
of carbon monoxide can
cause potentially fatal car-
bon monoxide poisoning.
Observe the safety instruc-
tions at the beginning of this
manual.
Determine the cause of the in-
creased CO level. Remedy the
fault.
Press Test on the CO limiter.
The alarm is switched off.
Replace the CO limiter.
If the system is to be temporarily
operated without CO limiter, set
parameter 49:0.
Fit flue gas temperature sensor
correctly (see page 106).
Replace programming unit
Vent the system if the fault mes-
sage continues to be displayed
Check circulation pump
Check flue gas temperature sensor
and connecting lead.
Check connections and replace
programming unit if required
Replace the control unit
Replace the control unit
93