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T-Product · BCU 465 · 2006 April
Troubleshooting
Fault codes (?), Possible Causes (!) and Solutions (
•
)
? The display flashes and dis-
plays
01
?
!
The BCU has detected a flame
signal simulation without the
burner having been ignited (ex-
traneous signal)
!
The UV tube in the UV sensor
UVS is defective and permanent-
ly indicates an extraneous signal
• Exchange UV tube, order part #
04065304 – note the operating
instructions for the UV sensor
!
Flame signal through ceramic in-
sulation
• Increase value of parameter 04
in order to adapt the switch-off
threshold of the flame amplifier
? The display flashes and dis-
plays
0
?
!
The BCU has detected that the
Proof of Closure Switch (OCS)
input has got no proof of closure
signal in standby position.
• Make sure that the wiring is cor-
rect. The BCU needs line voltage
when valve is closed and no volt-
age signal when valve is opened.
• If the wiring is correct, check the
switch and the valve for proper
operation. Remove the valve im-
mediately if you have any doubt
of correct close position.
? The display flashes and dis-
plays
X
?
!
The BCU has got no information
that the OCS contact is still open.
• Make sure that the wiring is cor-
rect. The BCU needs line voltage
when valve is closed and no volt-
age signal when valve is opened
during start-up.
• If the wiring is correct, check the
switch and the valve for proper
operation. Remove the valve im-
mediately if you have any doubt
of correct operation.
? At start-up, the display flash-
es and indicates
2
?
!
The BCU has got no informa-
tion that the OCS contact has
opened.
• Make sure that the wiring is cor-
rect. The BCU needs line voltage
when valve is closed and no volt-
age signal when valve is opened
during start-up.
• If the wiring is correct, check the
switch and the valve for proper
operation. Remove the valve im-
mediately if you have any doubt
of correct operation.
? At start-up – no ignition spark
occurs – the display flashes
and indicates
02
?
!
Ignition cable is too long.
• Shorten it to 1 m (maximum 5
m).
!
Distance between ignition elec-
trode and burner head is too
large.
• Set a distance to 2 mm maxi-
mum.
!
Ignition cable not making contact
in the electrode plug.
• Screw the cable on firmly.
!
Ignition cable has a short-circuit
to ground.
• Check the cable along its length
and clean the ignition electrode.
? At start-up – no gas supply
– the display flashes and indi-
cates
02
?
!
The gas valve V1 is not opening.
• Check the electrical power sup-
ply to the gas valve.
!
There is still air in the pipe (ex-
ample: after installation work has
been completed or when the
system has not been in opera-
tion for a long period of time).
• Reset repeatedly until gas line
fills with gas.
