Boiler Water Temp; Flow Temperature - Viessmann VITOLADENS333-F Service Instructions Manual

Fault codes
(cont.)
Fault code System character-
on the dis- istics
play
20 Regulates without

flow temperature

sensor (low loss
header)
28 Regulates without
flow temperature
sensor (low loss
header)
30 Burner blocked
38 Burner blocked
40 Mixer closes
48 Mixer closes
50 No DHW heating
58 No DHW heating
A7 Control mode as per
delivered condition
b0 Burner blocked
b1 Control mode as per
delivered condition
Cause Measures
System flow tem- Check the low loss
perature sensor header sensor (see
shorted out page 75).
System flow tem- Check the low loss
perature sensor header sensor (see
lead broken page 75).
Boiler water tem- Check the boiler water
perature sensor temperature sensor (see
shorted out page 75).
Boiler water tem- Check the boiler water
perature sensor temperature sensor (see
lead broken page 75).
Heating circuit Check the flow tempera-
with mixer M2 ture sensor.
flow temperature
sensor shorted
out
Heating circuit M2 Check the flow tempera-
flow temperature ture sensor.
sensor lead bro-
ken
Cylinder tempera- Check the sensor (see
ture sensor page 75).
shorted out
Cylinder tempera- Check the sensor (see
ture sensor lead page 75).
broken
Faulty program- Replace the program-
ming unit ming unit.
Flue gas tem- Check the flue gas tem-
perature sensor perature sensor (see
shorted out page 77).
Communication Check connections and
fault; program- replace the program-
ming unit (inter- ming unit if required.
nal)
Troubleshooting
69