Technical data

6 720 611 445 GB (03.11)
42 Appendix 9.5 Operational Flow diagrams 9.5.1Central heating function Fig. 61
6 720 611 137 - 24.1O
External Pump
remains ON.
External
Mains
switch
ON.
Fan min.
speed for
90 secs.
Green
light
ON.
Burner lights.
Red light ON.
Ignition spark for
5seconds.
Fan runs to purge
gas from burner.
Room thermostat
and/or mains
programmer or
link ON
Temperature
contro
l
knob
ON.
Heat
demand.
Pump ON
Fan to
start speed.
Gas va lve opens.
Burner
stabilises at
start speed
for 5-10 secs
Fan speed
reduces
over 15
secs.
Gas va lve
closes.
Red light
OFF.
*
Minimu m
heat input
for 15min.
Boiler
operates to
ma tch
system load
an
d
temperature
control
setting.
Boiler
unused for
long
period.*
Over temperat ure
shut-down if water
temperature is 5°C
above set value.
Burner remains OFF
until flow temperature
is below set value.
Gas valve
External pump
remains ON
shuts.
Heat
demand
satisfied.
Yes
No
Yes
No
*NOTE: Thesequence ensures that the condensate siphon is not empty
after long
OFF
periods. (More than 24 hours without a dema nd).
Ignition sequence
External
Repeats 5 times
(N.G.) or 3 times
(L.P.G.) before
lock out