7
221785B
The flue must be installed in accordance with the
recommendations in the current issue of BS5440 Part 1.
The flue should be kept as short as possible.
Horizontal or very shallow runs should be avoided.
Give maximum possible vertical rise from the boiler, minimum
600mm (24in) before any bend.
The use of 45
o
bends is recommended.
A slip-on loose collar must be provided for flue removal.
End with a certificated terminal, above ridge height, if possible,
if not, at least above the eaves of a pitched roof.
A previously used chimney must be swept and any register
plate or damper or the like must be removed or locked in the
open position and the chimney made good.
2.2 Boilers in a Compartment
Where the installation of the boiler will be in an unusual location,
special procedures are necessary. Refer to the current issue of
BS6798 for guidance.
A compartment used to enclose the boiler must be designed
and constructed specifically for this purpose.
An existing cupboard or compartment modified for the purpose
may be used. Refer to the current issue of BS6798 for
guidance.
The doorway opening should be of sufficient size to allow for
easy removal of the boiler.
Be provided with permanent ventilation openings as shown in
the respective Table 2. These figures are for the minimum free
area.
The high and low level openings must communicate with the
same room or space or must both be on the same wall to outside
air.
The compartment door or vent should not communicate with a
private garage, bedroom, bed sitting room or a room containing
a bath or shower.
2.2A Boilers in a Room or Space
A purpose designed ventilation opening must be provided on an
outside wall of the building, this opening may be either, directly
into the room or space containing the boiler, or into an adjacent
room or space which has an internal permanent air vent of the
same size to the room containing the boiler.
Do not ventilate through a kitchen, private garage, bathroom or
toilet.
Vents through a cavity wall must be ducted.
If there are other fuel burning appliances present, allowance
must be made for their combustion requirements. The free area
for the boiler is:
40CF - 38cm
2
(5in
2
)
Refer also to the current issue of BS5440 Part 2.
2.3 Products of Combustion
Test the boiler for clearance of flue products at the draught
diverter as detailed in the current issue of BS5440 Part 1.
2.4 Extract Fans
If an extract fan is fitted there is a possibility that if adequate air
is not provided spillage of the flue products could occur. If vents
are fitted in accordance with the above recommendations this
should not occur.
Where such an installation is found a spillage test must be
carried out as detailed in the current issue of BS5440 Part 1 and
any necessary action taken.
2.5 Timber Frame Buildings
If the boiler is to be installed in a timber frame building it should
be fitted in accordance with the Institute of Gas Engineers
document IGE/UP/7/1998. If in doubt seek advice from the local
gas undertaking or Hepworth Heating Ltd.
Frost Protection
If the position of the boiler is such that it may be vulnerable to
freezing it should be protected as specified in the current issue
of BS5422. It is also recommended that a frost protection
thermostat be fitted.
3.1 Cylinders
For all systems supplying domestic hot water the cylinder must
be indirect. It is recommended that the cylinder be fitted with
some form of temperature control.
3.2 Gravity Domestic Hot Water with Pumped
Heating
It is important that the flow and return connections are in the
same relative positions as shown in diagram 3.1.
The domestic flow and return must both be on one side of the
heat exchanger. The heating flow and return are taken from the
other.
2 Flue and Ventilation
3 Water Systems
27 metres
Max.
28mm
PUMP
MIDWAY BETWEEN
BOILER TAPPINGS
HEATING
SYSTEM
INDIRECT
CYLINDER
(Shown with
recommended
thermostat and valve).
22mm VENT
15mm COLD FEED
REFER TO BS 5546
Diagram 3.1
GRAVITY HOT WATER
SYSTEM (DIAGRAMMATIC)
