andrews 24/39 Installation And Service Manual page 21

Fig. 5
Heater with
highest usage
fitted nearest to
main flue
(if applicable)
Minimum Heights from Roof to Base of Flue Terminal
Type of Roof
Pitch
exceeding
45°
Pitched
Pitch not
exceeding
45°
With
parapet
Flat
Without
parapet
Issue 2 14/07/16
Each unit has an
atmospheric
burner system &
uses natural gas.
Not within 1.5m of a
vertical surface of a
structure = on the roof
Internal Route
On Ridge
Not on Ridge
1m
above roof
At or
intersection
above
ridge
600mm
level
above roof
intersection
600mm
above roof
intersection
Not
applicable
250mm
above roof
intersection
Fig 5.
Common flues may be used on multiple installations only if all
the heaters are of the same burner system and fuel type and
should be sized to ensure complete evacuation of the flue
products from the installation.
Where one flue is to be used more regularly or for longer
periods than the others in the group, it should be connected at
the point nearest to the main flue.
See
See BS 6644 Clause 20 for further information and
recommendations on this as well as general flue
requirements.
Fit a flue clip or flange joint close to the diverter so that it is
secure but can be disconnected for servicing. The weight of the
flue must be borne by securing clips, etc. and not by the heater.
Within 1.5m of a
vertical surface of a
structure = on the roof
External Internal
Route Route
1m
above roof
intersection
The base of the
The base of
terminal should
the terminal
be 600mm
should be
above the level of
600mm
the adjacent roof
above the
level of the
adjacent
roof edge
External
Route
edge
Installation 3
21