Operating instructions

53
Message
System characteristics Cause Measures
68 Buffer cylinder sensor
Buffer cylinder is heated
once every hour. Heating
stops according to set
value of the return tem-
perature sensor.
Break, buffer cylinder
temperature sensor
Check resistance (Pt 500)
at plug-in connection F4
and terminals X5.6/X5.7;
replace sensor if
required.
70 Room sensor HC1
■ No frost protection
mode via room temper-
ature sensor
■ No room temperature
hook-up
■ No room temperature
control
Short circuit, room tem-
perature sensor heating
circuit A1
Check remote control
sensor and replace if
required (see Vitotrol
service instructions).
71 Room sensor HC2
■ No frost protection
mode via room temper-
ature sensor
■ No room temperature
hook-up
■ No room temperature
control
Short circuit, room tem-
perature sensor heating
circuit M2
Check remote control
sensor and replace if
required (see Vitotrol
service instructions).
73 Room sensor SKK
Short circuit, room tem-
perature sensor, cooling
circuit
Check resistance (type Ni
500) at plug-in connection
F16; replace sensor if
required.
78 Room sensor HC1
■ No frost protection
mode via room temper-
ature sensor
■ No room temperature
hook-up
■ No room temperature
control
Break, room temperature
sensor heating circuit A1
Check remote control
sensor and replace if
required (see Vitotrol
service instructions).
Troubleshooting
Messages
(cont.)
5441 603 GB
Service