Troubleshooting - Viessmann VITOTRONIC 300 GW2 Installation And Service Instructions Manual

Diagnosis
(continued)
Faults with fault display on the programming unit (continued)
Fault code
Behaviour of system
in display
Controlled operation
0f
Operates on basis of 0°C outdoor
10
temperature
Operates on basis of 0°C outdoor
18
temperature
Burner is switched on and off by the
30
adjustable high limit
Burner is switched on and off by the
38
adjustable high limit
Mixing valve is closed
40
Mixing valve is closed
44
Mixing valve is closed
48
Mixing valve is closed
4c
DHW tank heating pump ON:
50
Desired boiler temperature = desired
DHW tank temperature, priority controls
are cancelled.
In conjunction with DHW tank heating
system:
DHW tank heating is switched on and off
by DHW tank temperature sensor 2.
In conjunction with DHW tank loading
51
system:
DHW tank heating is switched on and off
by DHW tank temperature sensor 1.
DHW tank loading pump ON:
58
Desired boiler temperature = desired
DHW tank temperature, priority controls
are cancelled.
In conjunction with DHW tank loading
system:
DHW tank heating is switched on and off
by DHW tank temperature sensor 2.
In conjunction with DHW tank loading
59
system:
DHW tank heating is switched on and off
by DHW tank temperature sensor 1.
Cause of fault
Service required
"0F" is only displayed
in the fault history
Short circuit
Outdoor temperature sensor
Open circuit
Outdoor temperature sensor
Short circuit
Boiler temperature sensor
Open circuit
Boiler temperature sensor
Short circuit
Supply temperature sensor of
mixing valve circuit M2
Short circuit
Supply temperature sensor of
mixing valve circuit M3
Open circuit
Supply temperature sensor of
mixing valve circuit M2
Open circuit
Supply temperature sensor of
mixing valve circuit M3
Short circuit
DHW tank temperature
sensor 1
Short circuit
DHW tank temperature sensor
2
Open circuit
DHW tank temperature sensor
1
Open circuit
DHW tank temperature sensor
2

Troubleshooting

Action
Carry out maintenance
Please note:
After carrying out main-
tenance, set coding "24: 0".
Check outdoor temperature
sensor (see page 99)
Check outdoor temperature
sensor (see page 99)
Check boiler temperature
sensor (see page 101)
Check boiler temperature
sensor (see page 101)
Check supply temperature
sensor (see page 28)
Check supply temperature
sensor (see page 86)
Check supply temperature
sensor (see page 86)
Check supply temperature
sensor (see page 86)
Check DHW tank
temperature sensor
(see page 101)
Check DHW tank
temperature sensor
(see page 101)
Check DHW tank
temperature sensor (see
page 101)
Check DHW tank
temperature sensor (see
page 101)
81