Viessmann vitodens Technical Manual page 109

Vitodens in conjunction with solid fuel boilers
Routing the flue pipe in a twin duct
According to the recommendation of the Federal Association of chimney sweeps (ZIV bulletin no. 1.3.02 T) [Germany], it is possible to
route the plastic flue pipe with the flue pipe of a solid fuel boiler in a twin duct chimney, if
H the annular gap required for secondary
ventilation/combustion air supply is
maintained (see page 106), and the
solid fuel boiler flue provides a down-
draught pipe with a super-elevation
of 2 × D, but in any case a minimum
of 400 mm.
D
C
D
B A
A Vitodens flue pipe
B Flue pipe for solid fuel boilers
C Down-draught pipe
D Ventilation/secondary air
VITODENS
4.2 Design and sizing information for flue pipe connections
or
H the flue pipe terminal is made of
non-combustible material (e.g.
aluminium), and the length inside the
duct is approx. 300 mm and above the
duct end approx. 2 × D flue pipe.
A corresponding terminal piece is
available as accessory:
System size 60
part no. 7176 730
System size 80
part no. 7147 097
We recommend this version with
segregation for open and balanced flue
operations. Never reduce the terminal
piece.
D
C
B A
A Vitodens flue pipe
B Chimney for solid fuel boilers
C Separation made from
non-combustible material
D Terminal piece made from
non-combustible material
E Duct cover (on site)
or
Hthe thickness of the tabs of the full-wall
breeze blocks is at least 50 mm (see
diagram). Since flue gas from the solid
fuel boiler can be drawn in, we can only
recommend open flue operation for this
version.
E
E
B A
>50 mm
A Vitodens flue pipe
B Chimney for solid fuel boilers
C End piece of the plastic flue pipe
D Duct cover
E Ventilation/secondary air
F Full-wall breeze block chimney with a
tab thickness of > 50 mm
C
D
4
F
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