Buderus 800-24 Installation And Servicing Instructions page 43

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
Subject to modifications resulting from technical improvements !
Installation and servicing instructions condensing gas boiler 800 - 24/29/43/60 and 800 - 24T25/29T25 H/V • edition 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
Check the mains supply during operation (230V~)
Press the Reset button until "r" appears in the display
Action
– Check for a short circuit and replace the F3 fuse
(see subsection 5.3.3)
– 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
Servicing 5
Buderus • http://buderus-domestic.co.uk
43