Viessmann Vitodens 242-F Installation And Service Instructions Manual page 94

Troubleshooting
Fault codes
(cont.)
Fault code dis- System characteristics
played
20 Regulates without flow tem-
perature sensor (low loss
header)
28 Regulates without flow tem-
perature sensor (low loss
header)
30 Burner blocked
38 Burner blocked
40 Mixer closes
44 Mixer closes
48 Mixer closes
4C Mixer closes
50 No DHW heating
51 No DHW heating
58 No DHW heating
59 No DHW heating
92 No solar DHW heating.
94 No solar DHW heating.
9A No solar DHW heating.
9C No solar DHW heating.
94
Cause
Short circuit, system flow
temperature sensor
Lead break, system flow
temperature sensor
Short circuit, boiler water
temperature sensor
Lead break, boiler water
temperature sensor
Short circuit, flow temper-
ature sensor, heating cir-
cuit 2 (with mixer)
Short circuit, flow temper-
ature sensor, heating cir-
cuit 3 (with mixer)
Lead break, flow tempera-
ture sensor, heating circuit
2 (with mixer)
Lead break, flow tempera-
ture sensor, heating circuit
3 (with mixer)
Short circuit, cylinder tem-
perature sensor
Short circuit, outlet tem-
perature sensor
Lead break, cylinder tem-
perature sensor
Lead break, outlet temper-
ature sensor
Short circuit, collector
temperature sensor; tem-
perature sensor con-
&
nection on the solar con-
trol module.
Short circuit, cylinder tem-
perature sensor; tempera-
ture sensor connection
%
on the solar control mod-
ule.
Lead break, collector tem-
perature sensor; tempera-
ture sensor connection
&
on the solar control mod-
ule.
Lead break, cylinder tem-
perature sensor; tempera-
ture sensor connection
%
on the solar control mod-
ule.
Measures
Check low loss header sensor (see
page 103)
Check low loss header sensor (see
page 103)
If no low loss header sensor is
connected, set code 52:0.
Check boiler water temperature
sensor (see page 103)
Check boiler water temperature
sensor (see page 103)
Check flow temperature sensor
Check flow temperature sensor
Check flow temperature sensor
Check flow temperature sensor
Check cylinder temperature sensor
(see page 103)
Check the outlet temperature sen-
sor (see page 103)
Check cylinder temperature sensor
(see page 103)
Check the outlet temperature sen-
sor (see page 103)
Check collector temperature sen-
sor (see page 103)
Check cylinder temperature sensor
(see page 103)
Check collector temperature sen-
sor (see page 103)
Check cylinder temperature sensor
(see page 103)