Ferroli F24 Installation, Servicing And User Instructions Manual page 25

Ferroli F24
3.10 Electrical connection
The boiler must be connected to a single phase 230 V 50 Hz electricity supply with a 3 A max. fuse and a bipolar
switch with contact opening of at least 3 mm fitted between the boiler and the electricity supply. The boiler must
always be connected to an efficient earth installation. Under the electrical box, there is a 3 pole terminal board for
connecting the boiler to the mains (230 V 50 Hz) and a 2 pole board for connecting a room thermostat (RT). To connect,
undo the screws fixing the terminal board box and connect the wires, ensuring correct polarity of the terminals. It
should be noted that there is low voltage (24 V) between the room thermostat contacts.
When the boiler is connected to an electricity main, it is essential TO OBSERVE CORRECT POLARITIES (LIVE:
brown cable, NEUTRAL: blue cable, EARTH: yellow-green cable).
All wiring must conform to current I.E.E. regulations.
Note: 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.
Note - 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 voltage to the switch contacts will irreparably damage the circuit board.
Although this boiler can also be used without a room thermostat, you are recommended to install one
for the following reasons:
Greater comfort conditions due to more accurate control of room temperature.
Greater energy savings.
3.11 Differential air pressure switch (fig. 2 - part 45)
The differential air pressure switch is a safety device which allows the main burner to ignite only after having
verified that the fan is working correctly. If the difference in pressure between the flue gas discharge pipe and the
air intake pipe is not at least equal 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.
3.12 Checks
Fill the central heating system as described previously (3.08) and check there are no leaks in the domestic hot
water and boiler water circuits. Check 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 Installing a room thermostat (72) (fig. 42)
To connect the thermostat:
Open the electrical box on the base of the appliance and remove the "jumper cable" between terminals
3 and 4.
Connect the room thermostat (72) as shown in fig. 42.
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