Buderus 800 - Page 44

Servicing5
Wall-mounted condensing gas boiler Buderus 800 - Subject to modifications resulting from technical improvements!
44
Code Meaning
6C Ionisation message, but no flame
Possible
cause
Action
1 There is no flame, ionisation electrode doesn’t
glow, fan is turning
– Check wiring of the hot surface ignitor, measure the resistance
of the hot surface ignitor (should be between 50 and 300 Ohm).
Replace hot surface ignitor if necessary (see subsection 5.3.15
and subsection 5.3.16)
– Check the UBA’s F1 fuse, replace if necessary
2 There is no flame, ionisation electrode does
glow, fan isn’t turning
– Check the fan and KIM connectors and the UBA fuses
3 There is no flame, ionisation electrode and fan
are working
– Check and adjust the gas/air ratio (see subsection 2.2.4)
– Check for 24V – on the gas valve during start up
– Check the gas-supply pressure (see subsection 2.2.3), this
should be higher than 20 mbar for natural gas
– Check the earthing cable connections (yellow/green wire)
– Check the cabling on the ionisation electrode
4 There is a flame, but the flame disappears
when the fan starts up
– The gas valve doesn’t close properly. If there is still more than
20 V~ on the gas valve when there is no heat demand then
check the UBA by temporarily connecting a different UBA.
– Check ionisation electrode/circuit (see subsection 2.2.7)
– When both the UBA and the ionisation electrode/circuit are OK,
then replace the gas valve
– Press reset. If fault code remains than try to temporarily connect
a different UBA (see subsection 5.3.5)
Code Meaning
6H Flame dies out after gas valve is opened
Possible
cause
Action
1 Gas/air ratio not in order Check and adjust the gas/air ratio (see subsection 2.2.4)
2 Gas supply pressure may need adjusting Check the gas-supply pressure (see subsection 2.2.3),
this should be higher than 20 mbar for natural gas
3 Earthing cable may be faulty Check the earthing cable connections (yellow/green wire)
4 Ionisation electrode may be faulty Check the cabling on the ionisation electrode
Code Meaning
6L Flame goes out during warm-up phase
Possible
cause
Action
1 Gas/air ratio not in order Check and adjust the gas/air ratio (see subsection 2.2.4)
2 Gas supply pressure may need adjusting Check the gas-supply pressure (see subsection 2.2.3),
this should be higher than 20 mbar for natural gas
3 Earthing cable may be faulty Check the earthing cable connections (yellow/green wire)
4 Ionisation electrode may be faulty Check the cabling on the ionisation electrode