Maximum Vent/Air Intake Pipe Length - Horizontal/Vertical (Hybrid System); Horizontal Air Intake (Hybrid); Flashing And Storm Collar Installation - Viessmann Vitocrossal 300 CU3A Installation Instructions Manual

CU3A Venting Systems Installation
Vent Length Requirements
Flue
Legend
a Equivalent length (exhaust)
b Equivalent length (air intake)
c min. 18 in. (max. 48 in.)
(continued)
Maximum vent/air intake pipe length - horizontal/vertical
(hybrid system)
All PP(s) vent material and air intake (if PP(s) used) must
be ULC S636 or UL1738 listed.
The total equivalent length specified for a two pipe system
is the total combined length of the exhaust vent and air
intake pipe system. Do not exceed these maximum
lengths.
Note: For combination of different vent/air intake pipe
diameters, such as Ø 4 in. stainless steel vent with
Ø 3 in. (CVPC, PVC, ABS) air intake pipe, the total
equivalent length must be used for the smaller pipe
diameter.
Minimum vent length is 3.3 ft. (1 m).
Air
Maximum equivalent length -
vertical exhaust / horizontal air intake (hybrid)
Boiler model
CU3A 26, 35
CU3A 45, 57
A 7% boiler input reduction @ 60 m for all sizes and all
configurations.

Flashing and storm collar installation

Flashings and storm collars are field supplied.
Flashings and storm collars suitable for Type B vent
materials (or better) may be used.
To obtain flashings and storm collars, please contact
your local vent material supplier. Follow the installation
instructions supplied by the special venting manufacturer.
Follow local codes to properly isolate the exhaust vent
pipe when passing through floors, ceiling and roof.
Always check the marking on the pipe to make sure you
are using the correct material.
Direct Venting (Two-pipe System)
Intake Ø Exhaust Ø
3 in. 3 in.
(80 mm) (80 mm)
3 in. 4 in.
(80 mm) (110 mm)
Equivalent
length
198 ft.
(60 m)
198 ft.
(60 m)
37