Bosch Condens 7000 FP Installation And Service Instructions Manual page 58

Operating and fault displays
1)
Type Fault Sub Cause
code code
V 4Y 523 Interruption in the
floor standing
boiler
temperature
sensor.
B 5L 542 Incomplete
communication
with the burner
control unit.
B 5L 543 No
communication
with the burner
control unit.
58
Description Test procedure/Cause
Temperature at the Check sensor lead.
boiler water
Check plug-in connector.
temperature sensor too
low
(< -5 °C )
Check sensor readings against table.
Check the voltage values at the
sensor against the table.
The control unit Check the cable connections
generates this fault, if between the burner control unit and
not all the required data the control unit.
is supplied by the
burner control unit.
The control unit is not Check whether the cable plugs (BUS
receiving any data from cable and power cable) between the
the burner control unit. burner control unit and the control
Consequence: quick unit are correctly plugged in.
flashing of the reset
Check on the control unit whether
button on the burner
230 V is present at the terminals of
control unit (=
the "Mains combustion automatic
Emergency operation)
cut-out".
Check whether the connecting leads
(BUS and power cable) between the
burner control unit and the control
unit are damaged.
Check whether the reset button on
the burner control unit lights up
green.
Disconnect the BUS cable between
the burner control unit and the
control unit and check whether the
boiler enters emergency operation
(runs up 60 °C to boiler
temperature).
Check by replacing, whether the
burner control unit or the control unit
is faulty.
If the reset button on the burner
control unit does not light up, wait a
certain period of time, since the
device may not start up if the burner
control unit is cold.
Check whether the safety chain
(terminal 17/18 control unit) has
triggered.
Action
▶ Replace if damaged.
▶ Clean if dirty or replace if
necessary.
▶ Reconnect any loose plugs.
▶ Replace the temperature sensor,
if there are any deviations from
the table.
▶ If the connections are OK,
replace the burner control unit.
▶ Reconnect any loose plugs.
▶ Replace the control unit if 230 V
is present.
▶ Replace the connecting lead if
necessary.
▶ If the reset button does not light
up, replace the burner control
unit.
▶ If the floor standing boiler does
not start up, replace the burner
control unit.
▶ Replace the burner control unit
or control unit.
▶ Wait for max. 30 minutes and
check, whether the reset button
on the burner control unit then
lights up green again. If this is not
the case, replace the burner
control unit.
▶ Determine the cause of safety
chain triggering and resolve the
problem. Then reset the relevant
safety element.
Condens 7000 FP – 6721846699 (2022/12)