Bosch CR 400 Installation Instructions For Contractors page 52

52 | Troubleshooting
Cause or fault description
A31 3021 Heating circuit flow temp.
A32 3022 sensor
A33 3023
faulty - standby mode active
A34 3024
(A31/3021
A35 3025
= Heating circuit 1;
A36 3026
A32/3022
A37 3027
= Heating circuit 2;
A38 3028
A33/3023
= Heating circuit 3;
A34/3024
= Heating circuit 4;
A35/3025
= Heating circuit 5;
A36/3026
= Heating circuit 6;
A37/3027
= Heating circuit 7;
A38/3028
= heating circuit 8;)
A51 6021 Collector temperature sensor
faulty
A51 6022 Bottom temp. sensor cylinder
1 faulty.
Standby mode active
Table 25 Fault displays
6 720 820 872 (2016/12)
Test procedure / Cause
Check configuration. The selected setting
requires a flow temperature sensor
Check the connecting lead between heating
circuit module and flow temperature sensor
Check flow temperature sensor according to
table
Check the voltage at the terminals of the flow
temperature sensor at the heating circuit
module according to table
Check configuration. The selected setting
requires a collector temperature sensor
Check connecting lead between solar module
and collector temperature sensor
Check collector temperature sensor
according to the table
Check the voltage at the terminals of the
collector temperature sensor on the solar
module according to the table
Check configuration. The selected setting
requires a bottom cylinder temperature
sensor
Check connecting lead between solar module
and bottom cylinder temperature sensor
Check the electrical connection of the
connecting lead at the solar module
Check the bottom cylinder temperature
sensor according to the table
Check the voltage at the connecting terminals
of the bottom cylinder temperature sensor at
the solar module according to table
Action
Change configuration.
Establish a connection properly
If values do not match, replace the
sensor
If the sensor values matched, but
the voltage values do not, replace
the heating circuit module
Change configuration.
Establish a connection properly
If values do not match, replace the
sensor
If the sensor values matched, but
the voltage values do not, replace
the solar module
Change configuration
Establish a connection properly
If a screw or plug is loose, rectify
the contact problem
If values do not match, replace the
sensor
If the sensor values matched, but
the voltage values do not match,
replace the module
CR 400 | CW 400 | CW 800