Measuring Vent Length - Navien NCB-150E Installation & Operation Manual

6.3 Measuring Vent Length

The maximum vent length when using 2 in exhaust ducts is 60 ft
(18 m). The maximum vent length when using 3 in vent ducts
is 150 ft (45 m). The intake duct length may be identical to the
exhaust duct length. Maximum vent lengths reduces according to
the number of elbows used, as shown in the following table:
Maximum
Vent Size
Length
2 in.
60 ft (18 m)
3 in.
150 ft (45 m)
The Maximum Length does not include any elbows.
Note
If using a concentric termination as shown on
page 46, count this as 5 linear feet (1.5 m) of vent.
Maximum
Equivalent Length
# of Elbows
Reduce the
maximum vent
length accordingly
for each elbow used:
Each 90° elbow
6
equates to 8 linear
feet of vent
Each 45° elbow
equates to 4 linear
feet of vent
Reduce the
maximum vent
length accordingly
for each elbow used:
Each 90° elbow
8
equates to 5 linear
feet of vent
Each 45° elbow
equates to 3 linear
feet of vent
6.4 Terminating the Vent
Before installing the boiler, determine what type of vent
termination is appropriate for the installation location and
situation. The subsections that follow describe some typical
venting configurations, but do not include all possible options.
The following PP components can be used as terminations:
Duravent
2PPS-E90L (2" 90° Elbow)
3PPS-E90L (3" 90° Elbow)
2PPS-E45L (2" 45° Elbow)
3PPS-E45L (3" 45° Elbow)
2PPS-TL (2" Tee)
3PPS-TL (3" Tee)
2PPS-BG (2" Birdscreen)
3PPS-BG (3" Birdscreen)
Centrotherm
ISELL0287 (2" 87° Elbow)
ISELL0387 or ISEL0387 (3" 87° Elbow)
ISELL0245 (2" 45° Elbow)
ISELL0345 or ISEL0345 (3" 45° Elbow)
IST02 (2" Tee)
IST03 (3" Tee)
IASPP02 (2" Birdscreen)
IASPP03 (3" Birdscreen)
Along with 2 in and 3 in PVC concentric terminations shown on
page 46, the following terminations can also be used:
IPEX Low Profile Termination Kits:
2 in Low Profile Vent Kit #196984
3 in Low Profile Vent Kit #193985
Duravent PolyPro Horizontal Concentric Termination Kit
2 in x 4 in Concentric Vent Kit #2PPS-HKL
3 in x 5 in Concentric Vent Kit #3PPS-HKL
Refer to the vent manufacturer's instructions for detailed
installation procedures.
CAUTION
Minimum Clearance to Metering devices and Relief
equipment. Maintain a minimum horizontal clearance of
4 ft (1.22 m) from electric meters, gas meters, regulators, and
relief equipment. Do not install the boiler above or below
electric meters, gas meters, regulators, or relief equipment
unless a 4 ft (1.22 m) horizontal clearance is maintained.
Refer to the figure below for the orientation of vent
termination if the IPEX low profile vent kit is used for
termination.
Venting the Boiler 45