Terminations; Clearances From Wall; Distance Between Flue Outlet & Air Inlet - Keston Qudos 28s User, Installation And Servicing Instructions

WD420/3/2007 Chapter 3 - Boiler Location
3.8.4

Terminations

Air inlet terminals must be facing horizontally or downwards to prevent entry of rain into
the terminal and positioned to ensure only fresh air is drawn into the boiler. The air
terminal must be located outside of the building.
Flue and air terminals must be positioned so that flue products are not drawn into the air
inlet. Site specific wind conditions should be considered to achieve this.
Drawing of combustion air directly from a ventilated boiler room invalidates the heat
exchanger warranty.
The flue outlet terminal is designed to face outwards but can, if desired, be adapted to
face in any direction BUT must not be directed in the region of the air inlet. The flue
terminal and air inlet terminal can be located on different, but not opposing wall faces.
The two terminals are subject to the requirements of BS 5440 Pt 1 for clearances from
features of the building although some can be decreased to the values indicated.
The Keston Qudos 28s and Qudos 28sP, as with any condensing boiler, will
generate a condensate "plume" from the flue terminal in all weather conditions.
Consideration must therefore be given to the effect of this "plume" when selecting
a location for the flue terminal. It is the responsibility of the installer to ensure the
selected terminal location does not cause nuisance.
A Below, above or beside openable window, air
brick, etc.
B Below gutters, soil pipes, drain pipes.
C Below eaves.
D Below balconies or car port roof (lowest point).
E From vertical drain or soil pipes.
F From internal or external corner or to a
boundary alongside the terminal. *
G Above ground or balcony or roof.
H From surface or boundary facing a terminal. *
I From terminal facing a terminal.
J From opening in a car port.(not recommended)
K Vertically from terminal on same wall.
L Horizontally from terminal on same wall.
*The dimensions given in the table above may need to be increased to avoid wall staining
and nuisance depending on site conditions.
It is advisable for horizontal flue terminals to place a 45
direct the condensate plume up and away from the property. If the air intake is within
500mm of the flue outlet the air must not terminate at a level above that of the flue
If either the air inlet or flue outlet terminate at a height of less than 2.1m above ground
level, the terminal must be protected by a suitable guard. The K4 terminal guard (with
plastic coating), manufactured by Tower Flue Components Ltd is suitable for this purpose
3.8.5

Clearances From Wall

Flue outlet and air inlet terminations must be at least 40 mm from the wall face.
3.8.6 Distance Between Flue Outlet & Air Inlet
There is no maximum - the terminations must not be on opposite sides of the
dwelling but can be in areas of unequal pressure..
A minimum clearance of at least 200 mm must be left between the terminations.
Installation & Servicing Instructions
The Keston Qudos 28s & Qudos 28sP Boilers
Dimensions (mm) Flue Air
Terminal Inlet
300
75
200
200
75
200
200 100
600 100
1,200 1,200
1,200 100
1,500 1,500
300 300
o
elbow at the end of the flue to
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50
75
50
50
50
50