Buderus 800 - Page 45

Servicing 5
Wall-mounted condensing gas boiler Buderus 800 - Subject to modifications resulting from technical improvements!
45
Code Meaning
7A Voltage in burner-control unit too low (lower than 187 V~) or too high (higher than 246 V~)
Possible
cause
Action
1 Regulating device may have to cope with interference – Check if for example induction fields interfere with the
regulating device
– Check if the are any peaks in the electrical network
caused by maybe windmills or a power generator
Code Meaning
7C Mains supply interrupted
Possible
cause
Action
1 A problem with the mains supply Check the mains supply during operation (230V~)
2 Reset button pressed too briefly Press the Reset button until "r" appears in the display
Code Meaning
7F F3 fuse defect, or burner control unit error
Possible
cause
Action
1 Short circuit in the 24V circuit (three-way-valve or
connector)
– Check for a short circuit and replace the F3 fuse
(see subsection 5.3.3)
2 Regulating device may have to cope with interference – Check if for example induction fields interfere with the
regulating device
– Check if the are any peaks in the electrical network
caused by maybe windmills or a power generator
Code Meaning
7H Voltage peaks in the UBA
Possible
cause
Action
1 Regulating device may have to cope with interference – Check if for example induction fields interfere with the
regulating device
– Check if the are any peaks in the electrical network
caused by maybe windmills or a power generator
Code Meaning
7L Internal UBA error
Possible
cause
Action
1 Regulating device may have to cope with interference – Check if for example induction fields interfere with the
regulating device
– Check if the are any peaks in the electrical network
caused by maybe windmills or a power generator