Operating instructions

54
Message
System characteristics Cause Measures
79 Room sensor HC2
■ No frost protection
mode via room temper-
ature sensor
■ No room temperature
hook-up
■ No room temperature
control
Break, room temperature
sensor heating cir-
cuit M2
Check remote control
sensor and replace if
required (see Vitotrol
service instructions).
7B Room sensor SKK
Break, room temperature
sensor, cooling circuit
Check resistance (type Ni
500) at plug-in connection
F16; replace sensor if
required.
92 Collector sensor
Collector temperature
sensor shorted out.
Check resistance (Pt 500)
at plug-in connection F21
and terminals X6.10/
X6.11; replace sensor if
required.
If the Vitosolic is connec-
ted, check the Vitosolic
sensor (see Vitosolic
service instructions).
93 Return sensor solar
Return temperature sen-
sor short circuit
Check resistance (Pt 500)
at plug-in connection F18
and terminals X6.6/X6.7;
replace sensor if
required.
If the Vitosolic is connec-
ted, check the Vitosolic
sensor (see Vitosolic
service instructions).
Troubleshooting
Messages
(cont.)
5441 603 GB