Viessmann Vitoclima 300-S Service Instructions For Contractors page 20

Troubleshooting
Diagnosis
(cont.)
No. Fault code
5 4 3 2
05
06
07
08
09
10
11
12
13
14
15
16
17
18
20
Fault
1
Processor temperature
sensor not connected
(if enabled)
Processor temperature
sensor short circuit (if
enabled)
Outside temperature
sensor not connected
(if enabled)
Outside temperature
sensor short circuit (if
enabled)
Suction gas tempera-
ture sensor not con-
nected (if enabled)
Suction gas tempera-
ture sensor short cir-
cuit (if enabled)
Processor fault
EEPROM faulty
DC undervoltage
DC overvoltage
AC undervoltage
Communication error
No communication
Non-approved external
unit
Cause/Remedy
Check sensor connection;
replace sensor
Check sensor connection;
replace sensor
Check sensor connection;
replace sensor
Controller problem: Check
the connecting cable and
jumper settings; replace con-
troller
Device operates with ROM
parameters; replace control-
ler
Check the voltage at the ex-
ternal unit
Incompatible controllers of
the internal device and the
external unit: Replace the
controller of the internal de-
vice
Check the connecting cable
between the internal device,
the external unit and earth