Viessmann VITODENS 333-F WS3A Service Instructions Manual page 74

Troubleshooting
Fault codes
(cont.)
Fault Const. Weath.-
code comp.
on the
display
28 X X
30 X X
38 X X
40 X
48 X
50 X X
51 X X
58 X X
74
System char- Cause
acteristics
Regulates System flow
without flow temperature
temperature sensor lead
sensor (low broken
loss header)
Burner Boiler water
blocked temperature
sensor
shorted out
Burner Boiler water
blocked temperature
sensor lead
broken
Mixer closes Heating cir-
cuit with
mixer M2
flow tem-
perature
sensor
shorted out
Mixer closes Heating cir-
cuit with
mixer M2
flow tem-
perature
sensor lead
broken
No DHW heat- Cylinder
ing temperature
sensor
shorted out
No DHW heat- Outlet tem-
ing perature
sensor
shorted out
No DHW heat- Cylinder
ing temperature
sensor lead
broken
Measures
Check the low
loss header sen-
sor (see page 83)
Check the boiler
water tempera-
ture sensor (see
page 83)
Check the boiler
water tempera-
ture sensor (see
page 83)
Check flow tem-
perature sensor
Check flow tem-
perature sensor
Check sensors
(see page 83)
Check sensors
(see page 83)
Check sensors
(see page 83)