Download Benchmark RD 542i combi Technical data

Mains
switch
ON.
50
Repeats 5 times
(N.G.) or 3 times
(L.P.G.) before
lock-out.
Green
light
ON.
CH
demand.
Ignition spark for
5 seconds.
Ignition sequence
Room
thermostat
and/or mains
programmer or
link ON AND
Electronic facia
programmer (if
fitted) ON AND
CH control
knob ON.
Fan runs to
purge gas from
burner.
No
Burner lights. Red
light ON.
Pump ON Fan to
start speed. Gas
valve opens.
Yes
Burner remains OFF
until flow temperature
is below set value.
Fan speed
reduces
over 15
secs.
CH demand
satisfied.
Fan min.
speed for
90 secs.
Yes
*Minimum
heat
input for
15min.
Gas valve closes.
Red light OFF.
No
Boiler
unused
for long
period.*
Over temperature
shut down if water
temperature is 5°C
above set value.
Pump and Fan
run for up to 3
mins.
Boiler
operates to
match
system load
and CH
control
setting.
6 720 610 576 - 26.TD
* NOTE: The sequence ensures that the condensate siphon is not empty
after long OFF periods. (More than 24 hours without a demand).
Burner
stabilises at
start speed for
5-10 secs
Gas valve shuts.
Pump remains ON.
Appendix
10.7.2 Central heating function
Fig. 66
6 720 611 447 GB (03.11)