Ferroli F24 Installation, Service And User Instructions Manual page 25

: If the power supply cable has to be replaced, use "0.75mm (24/0.20) heat resisting cable only to BS6500
with a maximum external diameter of 8 mm.
When connecting a room thermostat or external timer, do not link the power supply of these devices
to the switching contacts. The switch contacts must be voltage free. Any mains powered devices must utilise
mains power solely to drive the timer motor.
Applying mains v l ag
Although this boiler can also be used without a room thermostat, you are recommended to install one
for the following reasons:
reater comfort conditions due to more accurate control of room temperature.
reater energy savings.
3.11 Diff r n ial air pr ssur swi ch ( g. 2 part 45)
The differential air pressure switch is a safety device which allows the main burner to ignite only after having
veri ed that the fan is working correctly. If the difference in pressure between the ue gas discharge pipe and the
air intake pipe is not at least e ual to the minimum pressure switch calibration value, the pressure switch contacts
do not close and the gas valve is thus prevented from opening.
In addition, the electrical circuit of the boiler is designed so that if for any reason the air pressure switch contacts
remain closed when the fan stops, the burner will not start up again.
3.1 h c s
ill the central heating system as described previously ( .08) and check there are no leaks in the domestic hot
water and boiler water circuits. heck that there are no gas leaks on the boiler or the supply to the boiler. Also
check that the electrical connections are correct.
3.13 ns alling a r m h rm s a
To connect the thermostat:
pen the electrical box on the base of the appliance and remove the " umper cable between terminals
and 4.
onnect the room thermostat (72) as shown in g. 42.
h swi ch c n ac s will irr parably damag
( g. 42)
h circui b ard.
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