Viessmann VITOCAL 300-G Installation And Service Instructions Manual page 152

Troubleshooting
Diagnosis (service scans)
A
Outside temperature sensor
0 Outside temp
3 Primary circuit flow temperature
(brine inlet temperature)
7 Primary circuit return tempera-
ture (brine outlet temperature)
B
1 Refrigerant circuit (compressor
stage 1)
DHW heating via heat pump
stage 1 (type BW)
Instantaneous heating water
1
heater at stage 1
or
or
Instantaneous heating water
2
heater at stage 2
or
or
Instantaneous heating water
3
heater at stage 3
45 Secondary circuit flow tempera-
ture
41 Secondary circuit return temper-
ature
Secondary pump
51 Hot gas temperature
Compressor stage 1 (type BW)
Primary pump (primary source,
common primary pump or pri-
mary pump heat pump stage 1)
152
(cont.)
C
2 Refrigerant circuit (compressor
stage 2)
DHW heating via heat pump
stage 2 (type BWS)
42 Secondary circuit return temper-
ature
Secondary pump
52 Hot gas temperature
Compressor stage 2 (type BWS)
Primary pump (primary source,
heat pump stage 2)
D
Solar circuit
50 Collector temperature (collector
temperature sensor)
29 Solar return temperature (cylin-
der temperature sensor)
or
DHW temperature sensor solar
cylinder (connected to the
Vitosolic)
Solar circuit pump
External heat source
or
or
If an external heat source is in
operation
External heat source mixer
45 Boiler temperature, external heat
source
Circulation pump for cylinder
reheating