Viessmann VITOTRONIC 200 Service Instructions Manual page 47

Messages
(cont.)
Message
Code/system characteris-
tics
72 Room temp. sensor HC3
■ No frost protection
mode via room temper-
ature sensor.
■ No room temperature
hook-up.
■ No room temperature
control.
73 Room temp. sensor SKK
No cooling mode.
78 Room temp. sensor HC1
■ No frost protection
mode via room temper-
ature sensor.
■ No room temperature
hook-up.
■ No room temperature
control.
79 Room temp. sensor HC2
■ No frost protection
mode via room temper-
ature sensor.
■ No room temperature
hook-up.
■ No room temperature
control.
7A Room temp. sensor HC3
■ No frost protection
mode via room temper-
ature sensor.
■ No room temperature
hook-up.
■ No room temperature
control.
Cause
Short circuit, room tem-
perature sensor in heat-
ing circuit with mixer M3.
Short circuit, room tem-
perature sensor, cooling
circuit.
Short circuit, room tem-
perature sensor, heating
circuit without mixer A1.
Lead break, room tem-
perature sensor in heat-
ing circuit with mixer M2.
Lead break, room tem-
perature sensor in heat-
ing circuit with mixer M3.
Troubleshooting
Measures
Check remote control and
replace if required (see
Vitotrol installation and
service instructions).
Check resistance (Ni 500)
at plug-in connection F16
(see page 172); replace
sensor if required.
Check remote control and
replace if required (see
Vitotrol installation and
service instructions).
Check remote control and
replace if required (see
Vitotrol installation and
service instructions).
Check remote control and
replace if required (see
Vitotrol installation and
service instructions).
47