Viessmann Vitodens 222-F Installation Instructions For Contractors page 62

Troubleshooting
Fault codes
(cont.)
Fault code dis- System characteristics
played
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
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 blocked
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
B7 Burner blocked
B8 Burner blocked
BA Mixer regulates to 20 °C flow
temperature.
BB Mixer regulates to 20 °C flow
temperature.
62
Cause
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
Boiler coding card fault
Lead break, flue gas tem-
perature sensor
Communication error, ex-
tension kit for heating cir-
cuit 2 (with mixer)
Communication error, ex-
tension kit for heating cir-
cuit 3 (with mixer)
Measures
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.
Press reset button R.
If the system is to be temporarily
operated without CO limiter, set
parameter 49:0.
Fit flue gas temperature sensor
correctly
Replace programming unit
Vent the system if the fault mes-
sage continues to be displayed
Check circulation pump
Check the flue gas temperature
sensor (see page 71)
Check connections and replace
programming unit if required
Replace the control unit
Replace the control unit
Plug in or replace the boiler coding
card
Check the flue gas temperature
sensor (see page 71)
Check the extension kit connec-
tions and code
Check the extension kit connec-
tions and code