Bosch CONDENS 5000W - Boiler Operation Function

Fault finding and diagnosis
59
Bosch Condens 5000W – 6 720 646 195 (2018/10)
7.2 Boiler operation function
NO
YES
MAINS
POWER
SUPPLY
ON
BOILER
DEMAND
Fan to
start
speed.
Pump ON.
IGNITION
SEQUENCE
(see detail)
BLUE
LIGHT
ON
BURNER
LIT?
GREEN
FLAME
LIGHT
ON
Stop spark
and gas.
Wait
10 seconds
5th
attempt?
LOCKOUT
10 second
stabilisation
period.
Fan
modulation
to achieve
set
temperature
(40-82°C)
END OF
BOILER
DEMAND
Gas valve
OFF
Pump run 3
minutes
Fan run 30
seconds
Over temperature shut-
down if water tempera-
ture is 5°C above set
value.
Gas valve OFF.
Fan overrun
30 seconds
3 minute pump
over run
Spark
ignition and gas
4 seconds
NO
YES
Room
thermostat and/or
mains
programmer ON
(or link fitted at
ST10)
AND
Facia mounted
programmer (if
fitted) ON
AND
CH control knob
ON
IGNITION SEQUENCE
6720644743-39.1Wo