Potterton PRIMA 30C User Manual page 6

SITE REQUIREMENTS - Page 6
This opening may be:
a Directly into the room or space containing the boiler or,
b Via a duct through the wall or roof of the room, (where
such a method is considered British Gas should be
consulted) or,
c Into an adjacent room or space which has an internal
permanent air vent of the same size to the room
containing the boiler. It is undesirable to ventilate via a
kitchen, bathroom or toilet.
The air vent should be sited as far as possible from any
extract fan to avoid short circuiting. To avoid the possibility of
freezing water pipes, the vent should not be sited near pipes.
The minimum effective area of the permanent air vent must
be:
30C 22 sq cm
40C 39 sq cm
50C 56 sq cm
60C 74 sq cm
If the room (e.g. kitchen) from which air is drawn, has an
extract fan fitted, then the opening size of the permanent air
vent should take this into account to ensure that the
operation of the boiler flue is not adversely affected when the
extract fan is running with all doors and windows closed.
This should be checked in accordance with BS5440 Parts 1
and 2.
3. Grilles and Ducts
Any grille and/or duct should be so sited and of a type not to
become easily blocked or flooded and should offer low
resistance to air flow.
FLUE
A 100mm (4in) internal diameter flue must be connected to
this appliance to evacuate the products of combustion from
the boiler. The flue
3.4 sq in
6.0 sq in
8.7 sq in
11.5 sq in
connecting socket on the boiler is designed to accept flue
pipe to BS567.
If a fluepipe to BS715 is to be used an adaptor must be fitted
to the boiler connecting socket.
Reference should be made to The Building Regulations and
British Standard 5440 Part 1. The following notes have been
compiled for your guidance:-
a The flue pipe should be at least 25mm from any
combustible material, or when passing through a wall,
floor or roof, be separated from any combustible
material by a non-combustible sleeve enclosing an air
space of at least 25mm around the flue pipe.
b Ideally a flue should rise vertically to a termination point
which is unaffected by down draught or wind eddies.
Therefore, for practical purposes, the flue should have
the shortest run possible; 90° bends should be avoided.
The terminal should be at least above roof edge level
and must be of a type acceptable to British Gas.
c Wherever possible there should be at least 600mm (2ft)
of vertical flue from the boiler flue socket.
Note; A split socket should be fitted in this length.
d Horizontal runs should be avoided. If a near horizontal
length is unavoidable, it must be followed by at least
twice that length of vertical flue.
e Wherever possible internal stacks, lined if necessary,
should be used.
f All brick chimneys must be lined with a liner acceptable
to British Gas.
g Where condensation is likely a means of draining must
be provided.
h If an existing flue is being used, ensure that it has been
thoroughly swept before lining or connecting the boiler.
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