Air Supply; Air Supply For Room Sealed Balanced Flue Boilers - Grant Combi 70 V3 User's Installation Manual

5.4 Electricity supply
1 A 230/240 V ~ 50 Hz mains supply is required.
The boiler must be earthed.
2 The supply must be fused at 5 Amp and there must
only be one common isolator for the boiler and
control system, and it must provide complete
electrical isolation.
3 A fused double pole switch or a fused three pin
plug and shuttered outlet socket should be used for
the connection.
4 The power supply cable should be at least 0.75 mm²
PVC as specified in BS 6500, Table 16.
5 All the wiring external to the boiler must be in
accordance with the current I.E.E. Wiring Regulations.
6 Any room thermostat or frost thermostat used must
be suitable for use on mains voltage.
7 The boiler requires a permanent mains supply, do
not interrupt it with any external time control.
8 In the event of an electrical fault after installation
of the boiler, the following electrical system checks
must be carried out:- Short circuit, Polarity, Earth
continuity and Resistance to earth.
20
5 - GENERAL BOILER INFORMATION
Fig. 10 - Air supply for room sealed balanced flue boilers
Combi V3, Combi Max and Vortex Combi models
5.5

Air supply

See Figs. 10 and 11
A sufficient permanent air supply to the boiler should
be provided:
a For proper combustion of fuel and effective
discharge of combustion products to the open air.
b For the ventilation of any confined space in
which the boiler is installed to prevent
overheating of the boiler any equipment in and
near the boiler.
c For the satisfactory operation of any draught
stabiliser which may be fitted.
It should be both the designer's and installer's concern
that the air required for these functions be introduced
so as to cause as little discomfort as possible to the
building occupants and thus to offer them the least
temptation to obstruct the ventilators.
Further details may be obtained from BS 5410:1:1997.
Notes:
For a boiler fitted in a compartment, which is ventilated
as shown, no additional allowance is necessary.
Open flue - Extract fans, where needed, should be in
accordance with Section 4.4.7 in BS 5410 Part 1 1997.