Viessmann Vitodens 222-F Installation And Service Instructions Manual page 89

Fault codes
(cont.)
Fault code dis- System characteristics
played
4D Mixer is being closed.
50 No DHW heating
51 No DHW heating
58 No DHW heating
59 No DHW heating
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 109)
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 Regulates as if the outside
temperature were 0 °C.
B5 Control mode as per deliv-
ered condition
Cause
Incorrect assignment of
extension for mixer, heat-
ing circuit 3
Short circuit, cylinder tem-
perature sensor
Short circuit, outlet tem-
perature sensor
Lead break, cylinder tem-
perature sensor
Lead break, outlet temper-
ature sensor
CO limit exceeded
CO limiter sensor fault
Flue gas temperature sen-
sor incorrectly positioned.
No flame formation during
the sensor test.
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
Check and adjust rotary selector
S1 (see page 101)
Check sensors (see page 97)
Check sensor (see page 97)
Check sensors (see page 97)
Check sensor (see page 97)
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 99).
Repeat the test several times if
necessary.
Replace the programming unit.
Vent the system if the fault mes-
sage continues to be displayed.
Check circulation pump.
Check flue gas temperature sen-
sor.
Check connections and replace
programming unit if necessary.
Replace control unit.
Replace control unit.
89