Technical data

6 720 611 445 GB (04.05)
42
Appendix
9.5 Operational Flow diagrams
9.5.1 Central heating function
Fig. 62
Mains
switch
ON.
Fan min.
speed for
90 secs.
Green
light
ON.
Burner lights.
Red light ON.
Ignition spark for
5 seconds.
Fan runs to purge
gas from burner.
Repeats 5 times
before lock-out.
Room thermostat
and/or mains
programmer or
link ON
Temperature
contro
l
knob
ON.
Heat
demand.
Pump
ON
Fan to
start speed.
Gas valve opens.
Burner
stabilises at
start speed
for 5-10 secs
Fan speed
reduces
over 15
secs.
Gas valve
closes.
Red light
OFF.
*
Minimum
heat input
for 15min.
Boiler
operates to
match
system load
an
d
temperature
control
setting.
Boiler
unused for
long
period.*
Over temperature
shut-down if water
temperature is 5°C
above set value.
Burner remains OFF
until flow temperature
is below set value.
Gas valvee
shuts.
P
ump
and Fan
run
for upto
3 mins.
Heat
demand
satisfied.
Yes
No
Yes
No
* NOTE: The sequence ensures that the condensate siphon is not empty after long
OFF
periods. (More than 24 hours without a demand).
Ignition sequence
ce
6 720 611 137 - 24.1O
External Pump remains ON.
External
External