10
OVERHEAT THERMOSTAT
Two overheat thermostats E and Fare fitted to the appliance
which interrupt the electricity supply in the event of overheating. The
thermostats are reset manually.
If the appliance fails to light, check that the overheat thermostats
have not operated by pressing the reset buttons E and F. If the
overheat thermostats stop the appliance again call a service engineer.
NOTE: If the electrical supply to the appliance is interrupted at
the isolation switch or a power failure occurs whilst the burner is
firing, the boiler will normally relight automatically when the power
supply is restored. However, depending upon circumstances it may be
necessary to reset the overheat thermostats before the appliance will
operate.
TO LIGHT THE APPLIANCE
(O.F./B.F. ONLY)
See Figs 2 and 4.
Set the Operating Switch C (or programmer) to OFF. Switch off
the electricity supply. Remove the cabinet front panel by lifting off its
mountings. Turn the gas service cock Don. Check that the white
needle on the pressure gauge is not below the required pressure
(sealed systems only).
Push the grey gas control knob J fully in and hold. At the same
time repeatedly press and release the red piezo igniter button K until
the pilot lights. The pilot can be seen either through the pilot window
L(BF) or under the combustion
chamber door baffle (OF). When the
pilot lights, continue to hold the grey
gas control knob in for a further 15
seconds and then slowly release it.
CAUTION: If the pilot light goes out at
this, or any other stage, twist the grey
knob clockwise and release. Wait three
minutes, then repeat the lighting
procedure, holding in the grey gas
control knob for a little longer than
before.
Switch on the mains electricity
indicated by the Standby light G.
Turn the central heating temperature
control Bto max. Set the Operating
Switch C(or programmer) to HEATING
AND WATER and the burner will light.
Set the Operating Switch (or
programmer) to the required position.
Set the room thermostat, if fitted, to
the desired temperature. Set the
central heating temperature control B
to the required position.
Replace the cabinet front panel.
Fig. 4. O.F. & B.F. models with cabinet front cover removed
Circulating
pump
Domestic
hot water
high limit
thermostat
reset
button E
Expansion
vessel
Standby G
A
Demand H
Pilot observation window. B.F. only.
Located behind expansion vessel
Slot in front
cover. O.F.
only.
Red Piezo
igniter
button K
Heatbank
Water
diverter
valve
Gas control
knob J
Pressure
gauge
Gas
service
cock D
To observe pilot and burner
look in this direction
B C
