Viessmann Vitodens 300 - Page 78

Displayed
fault c ode
Con-
st.
Weat -
her-
com-
p.
System
character-
istics
Cause Remedy
28 X X Controls
without
flow tem-
perature
sensor
(low loss
header)
System flow
temperature
sensor lead
break
Check the low loss
header sensor (see
page 87)
30 X X Burner
blocked
Boiler tem-
perature sen-
sor shorted
out
Check the boiler
temperature sensor
(see page 87)
38 X X Burner
blocked
Boiler tem-
perature sen-
sor lead break
Check the boiler
temperature sensor
(see page 87)
40 X Mixer
closes
Heating circuit
M2 flow tem-
perature sen-
sor shorted
out
Check the flow tem-
perature sensor
48 X Mixer
closes
Heating circuit
M2 flow tem-
perature sen-
sor lead break
Check the flow tem-
perature sensor
50 X X No DHW
heating
Cylinder tem-
perature sen-
sor/comfort
sensor/loading
sensor
shorted out
Check sensor s (se e
page 87)
58 X X No DHW
heating
Cylinder tem-
perature sen-
sor/comfort
sensor/loading
sensor lead
break
Check sensor s (se e
page 87)
Checking and acknowledging faults (cont.)
78
Troubleshooting
5692 537 GB