Vent Length Requirements; Maximum Vertical Exhaust Vent Pipe Length And Vertical Air Intake Pipe Length - Viessmann Vitocrossal 300 CU3A Installation Instructions Manual

Direct Venting (Two-pipe System)

Vent Length Requirements

Maximum vertical exhaust vent pipe length and vertical air intake pipe length

Legend
a Equivalent length (exhaust)
b Equivalent length (air intake)
c 12 in. (305 mm) over max. local snow level
(check with your local weather office for details)
66
CU3A Venting Systems Installation
Maximum allowable equivalent length - vertical
Boiler Model System Ø
See note below
CU3A 26, 35 3 in. (80 mm)
CU3A 45, 57 4 in. (110 or 100 mm)
A 7% boiler input reduction @ 60 m for all sizes and all
configurations.
Max. combined
equivalent vent
length (a+b)
149 ft. (45 m)
149 ft. (45 m)