Operating instructions
Troubleshooting
Logamatic EMS RC35 programming unit - Subject to technical modifications
48
10 
10 Troubleshooting
This fault table lists possible system faults, i.e. faults in EMS components. The heating system keeps 
operating as long as possible in the event of a system fault; in other words, heating can continue.
Only use original Buderus spare parts. Losses caused by the use of parts not supplied 
by Buderus are excluded from the Buderus warranty.
The fault displays are subject to the specific type of boiler used.
Abbreviations used:
SC = Fault code; x = heating circuit with number x, e.g. A23 for heating circuit 3
FC = Fault code
HCx = Heating circuit with the number x
SC FC
Events 
display
Effect on control 
characteristics
Possible cause Remedy
A01 800 Outside 
sensor is 
defect.
The minimum outside 
temperature is applied.
Temperature sensor is 
incorrectly connected 
or fitted.
Breakage or short cir-
cuit in the sensor lead. 
Temperature sensor is 
faulty.
B Check sensor 
connection and 
sensor lead.
B Check sensor 
mounting.
B Compare resistance 
values with the 
sensor curve.
A01 808 DHW sensor 
1 is defect.
DHW heating has 
stopped.
Temperature sensor is 
incorrectly connected 
or fitted.
Breakage or short cir-
cuit in the sensor lead. 
Temperature sensor is 
faulty.
B Check sensor 
connection and 
sensor lead.
B Check sensor 
mounting.
B Compare resistance 
values with the 
sensor curve.
A01 809 DHW sensor 
2 is defect.
Tab. 21 Fault table










