Viessmann Vitovalor 300-P Installation And Service Instructions For Contractors page 116

Troubleshooting
Fault codes for gas condensing module
Fault code dis- System characteristics
played
1A Circulation pump for dis-
charging buffer switches off
about 90 seconds after
switching on the control unit
1d Flow rate not being moni-
tored.
1E Flow rate not being moni-
tored.
1F Flow rate not being moni-
tored.
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 being closed
44 Mixer being closed
48 Mixer being closed
4C Mixer being closed
50 No DHW heating
51 No DHW heating
58 No DHW heating
59 No DHW heating
60 Fuel cell module shut down
61 Fuel cell module shut down
7C Circulation pump for dis-
charging buffer stopped
7d Circulation pump for dis-
charging buffer stopped
7E Circulation pump for dis-
charging buffer stopped
116
(cont.)
Cause
Communication error on
KM-BUS
No communication with
sensor
Flow sensor faulty
Flow sensor faulty
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
Communication error with
fuel cell
Fuel cell fault
Short circuit on return
temperature sensor aJ
Lead break on return tem-
perature sensor aJ
Short circuit on top buffer
temperature sensor A
)
Measures
Check KM-BUS connection to dif-
ferential temperature controller.
Check cables/leads and plugs.
Replace sensor.
Replace sensor.
Check low loss header sensor (see
page 127)
Check low loss header sensor (see
page 127)
If no low loss header sensor is
connected, set code 52:0.
Check boiler water temperature
sensor (see page 127)
Check boiler water temperature
sensor (see page 127)
Check flow temperature sensor
Check flow temperature sensor
Check flow temperature sensor
Check flow temperature sensor
Check cylinder temperature sensor
(see page 127)
Check the outlet temperature sen-
sor (see page 128)
Check cylinder temperature sensor
(see page 127)
Check the outlet temperature sen-
sor (see page 128)
Check LON connection
Inform Viessmann Technical Serv-
ices
Check the return temperature sen-
sor (see page 129)
Check the return temperature sen-
sor (see page 129)
Check top buffer temperature sen-
sor (see page 130).