Appendix
0020258016_01 ecoTEC pure Installation and maintenance instructions
39
Fault code
Meaning
Possible cause
F.71
Fault: Flow/return temperature sensor
Flow temperature sensor specifies a constant value: Flow temperature
sensor incorrectly attached to the flow pipe, flow temperature sensor de-
fective
F.72
Fault: Deviation in the water pressure
sensor/return temperature sensor
Flow/return NTC temperature difference too great
→
flow and/or return tem-
perature sensor defective
F.73
Fault: Water pressure sensor not con-
nected or has short-circuited
Interruption/short circuit of water pressure sensor, interruption/short to earth
in supply line to water pressure sensor or water pressure sensor defective
F.74
Fault: Electrical problem in the water
pressure sensor
Line to water pressure sensor has a short circuit to 5 V/24 V or internal fault
in the water pressure sensor
F.77
Fault: Condensate or smoke
Applies to: Installed condensate pump or flue non-return flap (optional)
Check the defective condensate pump or flue non-return flap
F.83
Fault: Dry fire
When the burner starts, the temperature change recorded by the flow or
return temperature sensor is non-existent or too small: Insufficient water in
the product, flow or return temperature sensor incorrectly attached to the
pipe
F.84
Fault: Flow/return temperature sensor
Values not consistent, difference between flow and return < -6 K
Flow and return temperature sensors signalling implausible values: Flow and
return temperature sensors have been inverted, flow and return temperature
sensors have not been correctly installed
F.85
Fault: Temperature sensor
The flow and/or return temperature sensors have been installed on the same
pipe/incorrect pipe
Temperature sensor not connected or is connected incorrectly
F.87
Fault: Ignition transformer cable
Ignition transformer cable harness not connected to the main PCB or it is
connected incorrectly, short circuit in the cable harness or damaged ignition
transformer
F.88
Fault: Gas valve assembly
Gas valve assembly not connected or it is connected incorrectly, short circuit
in the cable harness
F.89
Fault: Pump
Pump not connected or it is connected incorrectly, incorrect pump connec-
ted, short circuit in the cable harness
Err
Fault: Interface communication
Interface PCB not connected or connected incorrectly, short circuit in the
cable harness
