Vent And Combustion Air Pipe Lengths - Bosch Greenstar Series Installation And Service Instructions For Contractors

Notes on installation and operation
X
Y
1
Fig. 39 Vertical venting system (sealed combustion)
[1] Intake
[2] Exhaust
X Greater than 12 inches (305 mm)
Y Greater than 12 inches (305 mm)
1 2
Fig. 40 PolyPro Flex chimney cap (PP) flue gas routing (sealed
combustion)
[1] Intake
[2] Exhaust
42
X
2
6 720 641 933-08.1O
0010004964-001
X
Y
Fig. 41 Horizontal venting system (telescopic concentric vent kit)
6.8.3

Vent and combustion air pipe lengths

With Flex Pipe the maximum length is reduced by 50%. Flex Pipe
according to the suppliers instructions for use in the vertical part of the
installation only.
3" (76 mm) Vent and combustion air pipe
For all installation situations and for all appliances the maximum vent
and combustion air pipe length is 100 feet each, with no more than
8 elbows each.
2" (50 mm) Vent and combustion air pipe
The maximum total combined equivalent length of vent and combustion
air pipe ( tab. 17, 18 and 19) depend on the installation situation,
the appliance type and number of elbows used.
Installations  Fig. 32, 33, 34, 36, 37 and 39 Separate
terminations
2"-PIPE
Number of 90° elbows
used
1
2
3
4
5
6
Table 17 Vent and combustion air pipe lengths with 2" diameter and
separate terminations
1/4" per foot
(50 mm per meter)
6 720 641 933-78.1O
Maximum straight vent pipe length
allowed for Ø 2" pipe
ZBR 21-3A ZBR 35-3A
ZBR 28-3A ZWB 35-3A
ZWB 28-3A ZBR 42-3A
ZWB 42-3A
81 ft (24.6 m) 65 ft (19.8 m)
76 ft (23.1 m) 57 ft (17.3 m)
71 ft (21.6 m) 48 ft (14.6 m)
66 ft (20.1 m) 40 ft (12.2 m)
61 ft (18.6 m) 32 ft (9.8 m)
56 ft (17.1 m) 23 ft (7.0 m)
Greenstar – 6721822579 (2021/01)