103
Sensor
Captur-
ing ele-
ment
Installed loca-
tion
Connection
■ Collector temperature sensor
(F21)
NTC
20 kΩ
Internal unit (see
page 96)
Controller and
sensor PCB (see
page 49)
■ Compressor head temperature
sensor (hot gas) (CTT)
NTC
50 kΩ
External unit
(see page 98)
Refrigerant circuit
control (observe
label on the exter-
nal unit)
Temperature sensors in the internal unit (with marking)
Viessmann NTC 10 KΩ (blue marking)
Outside temperature sensor
100
10
-20 -10 0 10 20 30
Temperature in °C
6
8
20
40
60
80
200
Resistance in k
Ω
Further sensors
10
1
10 30 50 70 90 110
Temperature in °C
0.4
0.6
0.8
2
4
6
8
20
Resistance in k
Ω
Troubleshooting
Repairs
(cont.)
5623 661 GB
Service
