Ferroli TEMPRA 24 Installation, service and user instructions manual - Tempra 24
24
Tempra 24
3.09 Gas connection
Gas connection should be carried out using a rigid pipe.
The flow at the gas meter should be sufficient for the simultaneous use at full gas rate of all appliances
connected to it. Connect the gas supply to the boiler according to current regulations. The diameter of
the gas tube leaving the boiler is not the determining factor in choosing the diameter of the pipe between
the appliance and the meter. This must be selected in relation to length and pressure drop and in any
instance should not be less than 22mm.
The whole of the gas installation including the meter should be inspected and tested for soundness and
purged in accordance with BS6891-1988.
N.B. - The filling loop will be fitted by the installer in accordance with water by laws at the time of installing
the system. It is NOT a part of the boiler.
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 40)
The differential air pressure switch is a safety device which allows the main burner to ignite only after having veri-
fied 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 and check there are no leaks in the 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 and external time clock
To connect the external controls.
Open the electrical wiring box at back of PCB, connect switched line from electrical controls to terminal 2 (remove
factory link if fitted).