Operating instructions

66 | Fault mode
6 720 644 143 (2010/09)
17 Fault mode
17.1 Troubleshooting
All safety, modulation and control components are
monitored by the Heatronic system.
If a fault occurs during operation, a warning tone
sounds.
The display indicates a fault (e. g. ) and the reset-
button may also flash.
If the reset button flashes:
B Press and hold the reset button until the display
shows .
The appliance will start up again and the flow
temperature will be displayed.
If the reset button does not flash:
B Switch the appliance off and then on again at the main
switch.
The appliance will start up again and the central
heating flow temperature will be displayed.
If a fault persists:
B Check PCB, replace if required and set service
functions as per "Heatronic settings" label (Æ Fig. 37,
page 38).
DANGER: Risk of explosion!
B Turn off gas valve before working on gas-
carrying components.
B Check for leaks before working on gas-
carrying components.
DANGER: Risk of poisoning!
B Check for leaks before working on gas-
carrying components.
DANGER: Risk of electric shock!
B Before carrying out work on electrical
components, disconnect the power
supply (230 V AC) (fuse, circuit breaker)
and secure against unintentional
reconnection.
WARNING: Risk of scalding!
Hot water can cause severe scalding
B Drain the appliance before working on
components that carry water.
NOTE: Leaking water may damage the
Heatronic module.
B Cover the Heatronic module before
working on any parts that carry water.
If you press a button, the warning tone
stops.
For an overview of faults, see page 67.
For an overview of displays, see page 64.