Outside Temp. Sensor - Viessmann VITOTRONIC 200 Service Instructions Manual

Message overview
(cont.)

18 Outside temp. sensor

An outside temperature value of
culate the set flow temperature.
Cause
Lead break, outside temperature sensor
20 Flow sensor secondary
Operation with temperature value of return tempera-
■
ture sensor in secondary circuit, plus 5 K.
If the secondary circuit flow and return temperature
■
sensors are faulty at the same time, the message
"A9 Heat pump" appears and the heat pump shuts
down.
Cause
Short circuit, secondary circuit flow temperature sensor
21 Return sensor secndry
■ Operation with temperature value of flow tempera-
ture sensor in secondary circuit, minus 5 K.
■ If the secondary circuit flow and return temperature
sensors are faulty at the same time, the heat pump is
switched off. After 24 h the message "A9 Heat
pump" appears.
Cause
Short circuit, secondary circuit return temperature sen-
sor
24 Suction gas revers. temp.
■ Heating mode:
Heat pump remains in operation.
Cooling mode:
■
Compressor stops.
Cause
Short circuit, reversible suction gas temperature sensor Check resistance value (Pt500A) at terminals X25.15/
25 LPG temp. sensor
Compressor stops.
Cause
Short circuit, LPG temperature sensor
40 °C is used to cal-
–
Action
Check resistance value (NTC 10 k
"Controller and sensor PCB".
Measure
Check resistance value (Pt500A) at plug F8 or at termi-
nals X25.9/X25.10: See "Controller and sensor PCB".
Measure
Check resistance value (Pt500A) at terminals X25.11/
X25.12: See "Controller and sensor PCB".
Measure
X25.16: See "Controller and sensor PCB".
Measure
Check resistance value (Pt500A) at terminals X25.17/
X25.18: See "Controller and sensor PCB".
Troubleshooting
) at plug F0: See
Ω
79