Description of functioning
t e c h n i c a l
41
This may be caused by
a poor connection
of the 5-way cable joining the two
PCB's
;
“Err” may also appear very briefl y on the display when the boiler is plugged into the
mains or when entering auto-test mode; in this case it does not necessarily indicate
a failure.
In the A.S.S.
(Auto test unit)
the fault codes
are
store
d
in this way:
F18
F
2
1
, F2
2
Fault on
pressure switch system. During the start
before
u
p and before the fan runs
the APS contacts must be open lock out ocours after 3mins if the contacts remain
closed (F21)
If the contacts are open prior to the start up and fail to close afer 6 minutes then lock out
will ocour after a maximun time of 6 minutes if the contacts remain open. (F22)
F 31
Fault on water circuit of the boiler. The heating circuit is empty or the pressure detec-
ted
is lower than 0.5 bar
F 3
2
Fault on water circuit of the boiler. The
central low heating
pressure
switch is faulty
or disconnected
F 51, F 52, F 53, F 54, F 55, F56, F 57, F 58
These faults are internal electronic faults of the main control circuit.
F 61
Fault in fl ame detection. Detects fl ame in burner after closing gas valve.
F 62
Fault in fl ame detection. Detects fl ame for 10 seconds when the boiler is not dema-
n
d
ing the burner to burn.
F 63
Fault in fl ame detection. Detects fl ame in burner start before opening gas valve.
35
Ignition failure (F1)