61
if yes:-
(1) No flame visible before boiler shuts off:
gas valve or gas valve connections defective, repair
or replace as necessary (see Section 7.9)
(2) Flame is visible before boiler shuts off:
Turn the central heating control to the 'hot water
only' position and push the red 'reset' button. Enter
diagnostic mode, select d21 and push the right
button. Turn the central heating control back to the
'heating and hot water' position to operate the
appliance for heating. The boiler will attempt to
relight. Check the flame sensing system using
diagnostic code d.21 during the ignition cycle
(approx 10 seconds).
if
d21
=
0
, Check flame monitoring electrode and
lead for damage / correct connection.
Repair or replace as necessary.
if
d21
=
1
, CPU circuit board is defective.
Replace (see Section 7.22.4)
if
d66
=
3
, fault occurred during operation.
Check availability of adequate gas supply
(see section 5.8). if o.k. check for flue gas
recirculation caused by damage to burner
or condensate sump seals, check condensate
sump draw handle correctly fitted.
Repair or replace as necessary.
F22 or F23
1. System water pressure too low - Refill and
Lack of water in
repressurise the boiler to 1.2 bar (see Section 5.4).
system or
2. Circulating pump not operating - Enter diagnostic mode
poor/no water
(see Section 8.1), select '
d.10
' and press the right button.
circulation
Operate the boiler.
if
d10
=
1
check the electrical connections
to pump and that the pump is not seized.
Repair/replace the pump as necessary
(see Section 7.14).
if
d10
=
0
replace the CPU circuit board
(see Section 7.22.4).
F24
NTC 'T0'* and 'T1'* not giving comparable signals -
NTC Temperature
Check NTC 'T0' and 'T1' connecting leads for
comparison error
continuity and repair as necessary.
If fault still exists, replace NTC 'T0' and 'T1'.
* For location of NTC sensors refer to Section 2.4
Function diagram
F25
0.1A Fuse F3 defective. Replace with spare provided.
Faulty Fuse
(fuse has a resistance of approximately 20
Ω
).
F30 or F32 or F33
1. Air/flue duct obstructed
Lack of air flow
- check terminal is clear of obstruction, and the flue
through appliance
is correctly assembled with flue seals and air duct clamps.
2. Condensate drain obstructed
- check condensate discharge pipe not obstructed.
3. Faulty fan
- check fan performance using diagnostic codes
'
d.33
' and '
d.34
'. Enter diagnostic mode, select
'
d.33
' and press the right button. Operate the boiler.
Note the reading obtained.
Now select '
d.34
' and press the right button.
Compare the reading achieved on '
d.33
' (the required
fan speed) with the reading obtained on '
d.34
'
(the actual fan speed). If the actual fan speed reading
is more than 20 below the required fan speed
check the connections to the fan motor. If electrical
connections are satisfactory replace the fan
(see Section 7.2).
