Viessmann AWT 221.A04, Installation And Service Instructions For Contractors

Page: 74 / 140

74
2. Drain the heat pump at the secondary circuit fill &
drain valve (see chapter "Overview of internal com-
ponents: Internal unit").
Checking the sensors
Sensor Test ele-
ment Installed location Connection
■
Outside temperature sensor (F0)
■
Buffer temperature sensor (F4)
■
Cylinder temperature sensor (F6)
■
System flow temperature sensor (F13)
■
Cooling circuit flow temperature sensor (direct
heating circuit A1/HC1 or separate cooling
circuit SKK) (F14)
■
Room temperature sensors
NTC 10 k
Ω
Indoor unit (see
page 69) Controller and sensor
PCB (see page 34)
■
Secondary circuit flow temperature sensor
(F8)
■
Secondary circuit return temperature sensor
(F9)
Pt500A
(PTC) Indoor unit (see
page 69) Controller and sensor
PCB (see page 34)
■
Secondary circuit flow temperature sensor
upstream of the instantaneous heating water
heater (LWT)
■
Liquid gas temperature sensor (IRT)
NTC 10 k
Ω
Indoor unit (see
page 69) AVI PCB (see service
instructions
"Vitotronic 200,
type WO1C")
■
Temperature sensor, refrigerant inlet, evapo-
rator (OCT)
■
Temperature sensor, evaporator (OMT)
■
Temperature sensor, air intake, evaporator
(OAT)
NTC 10 k
Ω
Outdoor unit (see
page 70) Refrigerant circuit con-
troller (observe label on
the outdoor unit)
■
Temperature sensor, compressor head (hot
gas) (CTT) NTC 50 k
Ω
Outdoor unit (see
page 70) Refrigerant circuit con-
troller (observe label on
the outdoor unit)
Indoor unit: Viessmann NTC 10 k
Ω
(marked blue)
Outside temperature sensor
100
10
-20 -10 0 10 20 30
Temperature in °C
6
8
20
40
60
80
200
Resistance
in kΩ
Fig. 62
Other 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 kΩ
Fig. 63
Maintenance
Draining secondary side heat pump
(cont.)
5776 028 GB
Maintenance