Buderus 600 - 11S Installation And Maintenance Instructions Manual page 42

5 Servicing
Code Meaning
7A
Voltage in burner-control unit too low (lower than 187 V~) or too high (higher than 246 V~)
Possible
cause
1 Regulating device may have to cope with interference
Code Meaning
7C
Mains supply interrupted
Possible
cause
1 A problem with the mains supply
2 Reset button pressed too briefly
Code Meaning
7F
F3 fuse defect, or burner control unit error
Possible
cause
1 Short circuit in the 24V circuit (three-way-valve or
connector)
2 Regulating device may have to cope with interference
Code Meaning
7H
Voltage peaks in the UBA
Possible
cause
1 Regulating device may have to cope with interference
Code Meaning
7L
Internal UBA error
Possible
cause
1 Regulating device may have to cope with interference
Buderus • http://www.buderus-domestic.co.uk
42 Installation and maintenance instructions for wall-mounted condensing gas boiler 600 - 11S/19S/24S/24C • 02/2006
Action
– 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
Action
Carry out a power test procedure for safe testing of the
mains electrical supply
Press the Reset button until "r" appears in the display
Action
Check for a short circuit and replace the F3 fuse
– 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
Action
– 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
Action
– 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
Subject to modifications resulting from technical improvements!