47
Does yellow central heating
demand indicator ( ) glow?
Does bur
ner light?
Go to sheet H.
Check central heating control
switch is set to the position
( ).
Check Central Heating control and exter
nal controls
Sheet C
If the central heating demand
indicator ( ) still does not
glow
, replace electronic
boards.
Ye
s
Ye
s
No
No
Go to sheet D.
Is 230 V AC present across
boiler ter
minals 4 and 5?
Exter
nal fault. Check whether
all exter
nal controls are
calling for heat, replace or
repair as necessar
y (see also
note 1, sheet A).
No
Ye
s
No