Viessmann Vitotronic 100 GC1 Installation And Service Instructions Manual page 101

Faults displayed at the programming unit
Fault
System characteristics
code
4 4 4 4 0 0 0 0 Mixing valve closes
4 4 4 4 4 4 4 4
4 4 4 4 8 8 8 8
4 4 4 4 c c c c
5 5 5 5 0 0 0 0 DHW tank heating pump ON:
Set boiler temperature = set DHW
tank temperature, priority is cancelled
or
With DHW tank heating system:
DHW tank heating is started and
stopped by DHW tank temperature
sensor 2
5 5 5 5 1 1 1 1 With DHW tank heating system:
DHW tank heating is started and
stopped by DHW tank temperature
sensor 1
5 5 5 5 8 8 8 8
DHW pump ON:
Set boiler temperature = set DHW
tank temperature, priority is
cancelled
or
With DHW heating:
DHW heating is started and stopped
by DHW tank temperature sensor 2
5 5 5 5 9 9 9 9
With DHW heating:
DHW heating is started and stopped
by DHW tank temperature sensor 1
6 6 6 6 0 0 0 0
Boiler with maximum temperature,
no output reduction; return control no output reduction; return control
to to
6 6 6 6 8 8 8 8
(cont.)
Cause
Short circuit
Strap-on temperature sensor
of mixing valve circuit M2
Short circuit
Strap-on temperature sensor
of mixing valve circuit M3
Open circuit
Strap-on temperature sensor
of mixing valve circuit M2
Open circuit
Strap-on 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
Short circuit
Temperature sensor aJA
Open circuit
Temperature sensor aJA
Troubleshooting – Vitotronic 300-K, MW1S
Remedy
Check strap-on temperature sensor
(see page 126)
Check DHW tank temperature
sensor
(see page 125)
Check DHW tank temperature
sensor
(see page 125)
Check DHW tank temperature
sensor
(see page 125)
Check temperature sensor
(see page 126), (see page 126),
Set coding 4A : 0, if no sensor Set coding 4A : 0, if no sensor
is connected.
101