Bosch Condens 7000 F Installation And Maintenance Instructions For The Contractor page 48

Operating and fault displays
1)
Type Error 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.
48
Description Test procedure/Cause
Temperature at the boiler Check sensor lead.
water temperature sensor
Check plug-in connector.
too low
(< -5 °C)
Check sensor readings against table.
Check the voltage values at the
sensor against the table.
The control unit generates Check the cable connections
this fault, if not all the between the burner control unit and
required data is supplied the control unit.
by the burner control unit.
The control unit is not Check whether the cable plugs (BUS
receiving any data from the cable and power cable) between the
burner control unit. burner control unit and the control
Consequence: quick unit are correctly plugged in.
flashing of the reset button
Check on the control unit whether
on the burner control unit
230 V is present at the terminals of
(= Emergency operation)
the "Mains combustion automatic
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 to 60 °C 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 F – 6720871560 (2019/11)