Venting Options (Two-Pipe System) - Viessmann Vitocrossal 300 CU3A Installation Instructions Manual

CU3A Venting Systems Installation

Venting Options (Two-pipe System)

Legend
A Combustion air intake
B Boiler flue gas termination
C Combustion air CPVC adaptor*
* An 80 mm to 3 in. combustion air CPVC adaptor is
supplied with the boiler installation fittings.
Direct Venting (Two-pipe System)
The two-pipe venting system draws combustion air
A through a separate air intake pipe from the outdoors.
Flue gases B are discharged to the outdoors via the
single-pipe rigid-pipe and flexible vent system.
The two-pipe system is flexible in the selection of
materials offered by different manufacturers and the
location of the air intake termination.
Read the following exhaust vent/air intake requirements
carefully before commencing with the installation.
Boiler Flue Gas Exhaust Size
CU3A 26, 35 3 in. (80 mm)
CU3A 45, 57 4 in. (110 mm)
Intake
3 in. (80 mm)
3 in. (80 mm)
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