Roberts Gorden Blackheat BH15 UT Installation & Servicing Instructions Manual page 26

100 mm diameter
Fresh Air Intake Spigot
Figure 19. Fresh Air Intake Spigot
See section 7.2 for recommendations on duct length.
Air duct should be as straight as possible. Do not use
bends in excess of 45°. Consult the manufacturer if
more than 2 x 45° offset bends are necessary. The
fresh air duct must be self supporting.
7 7 . . 6 6 A A I I R R S S U U P P P P L L Y Y R R E E Q Q U U I I R R E E M M E E N N T T S S
When fresh air duct is used, follow one of these rules:
A. The flue must penetrate the roof while the fresh
air can penetrate any wall.
B. The flue and fresh air supply must penetrate the
same roof, at a minimum of one meter apart.
C. The flue must penetrate one meter higher than
the fresh air inlet on the same wall.
24
Burner
Dust Arrest
Baffle Plate
Roof
Inlet
Min. 1 m
Inlet
Flue
Min. 1 m Inlet
Figure 20. Air Supply with Flue Configurations
7 7 . . 7 7 C C O O M M M M O O N N D D U U C C T T
When using a common air inlet duct, always ensure
that the area of the common air inlet duct exceeds
the total area of all air ducts by 20%.
Flue
Wall
A
Flue
B
C