127
Fault mes-
sage
Cause Remedy Re-
set-
ting
"260: Flow
sensor 3"
Short circuit or lead break to
flow temperature sensor,
heating circuit 3.
Check flow temperature sen-
sor (see page 146)
"261: Loss
of flame Eng
bu"
After 5 attempts to start the
Stirling burner, the burner
control unit cannot detect a
flame.
Check the gas supply. Check
gas type setting (see
page 66).
Check electrodes (see
page 73).
Check function of gas train
and ignition transformer.
Check balanced flue system.
Ensure that flue gases are
not being recirculated.
UR
"262: Loss
of fl'Supp
bu"
"263: Eng bu
BCU failure"
Internal communication fault
in Stirling burner.
Switch mains power off and
on again. Carry out a restart.
If the fault has not been rec-
tified, replace the control unit
PCB (see page 138).
AR
"264: Supp
bu BCU fail-
ure"
Internal communication fault
in auxiliary burner.
"265: BCU
failure"
Internal communication fault. Carry out a service reset and
restart. If the fault has not
been rectified, replace the
control unit PCB (see
page 138).
SR
"266: Fan
fault"
Fan speed differs from set
value.
Check fan power cable.
Check fan for ease of opera-
tion. Replace fan if necessa-
ry.
SR
"267: Fan
calib fault"
Test speed not reached after
switching on.
"268: Spool
valve fault"
Faulty air distribution valve
feedback.
Check plug-in connection.
Remove air distribution valve
and check for blockage or
stiffness. If the valve moves
freely, replace the motor. If
the valve is stiff, replace the
valve.
SR
"269: Spool
valve calib"
Troubleshooting
Fault messages
(cont.)
5618 294 GB
Service
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