Navien NCB-190/060H, Installation & Operation Manual

Page: 63 / 145

63 Venting for Combustion Air
Ref Description
Canadian Direct Vent
Installations
1
US Direct Vent
Installations
2
E Clearance to unventilated soffit * *
F Clearance to outside corner * *
G Clearance to inside corner * *
H
Clearance to each side of center line extended above
meter/regulator assembly
3 ft (91 cm) within a
height 15 ft above
the meter/regulator
assembly
*
I Clearance to service regulator vent outlet 3 ft (91 cm) *
J
Clearance to nonmechanical air supply inlet to
building or the combustion air inlet to any other
appliance
36 in (91 cm) 12 in (30 cm)
K Clearance to a mechanical air supply inlet 6 ft (1.83 m)
3 ft (91 cm) above
if within 10 ft (3 m)
horizontally
L
Clearance above paved sidewalk or paved driveway
located on public property
7 ft (2.13 m) †
*
M Clearance under veranda, porch deck, or balcony 12 in (30 cm)
‡
*
1 In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code
2 In accordance with the current ANSI Z223.1/NFPA 54 National Fuel Gas Code
† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings
and serves both dwellings.
‡ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Clearance in accordance with local installation codes and the requirements of the gas supplier.
To use non-direct venting for the boiler:
1. Insert the termination end cap into the intake
air duct. Do not glue the end cap, to allow for
easy removal and cleaning of the cap.
Vent Termination
Cap 2"
Coupling 2"
Vent Pipe 2"
Non-Direct Venting (Single Pipe)
If, at any time, the installation location could
experience negative pressure, there is a possibility
of back drafting cold air through the boiler’s heat
exchanger. This situation could lead to the freezing
of the heat exchanger and malfunction of the boiler.
However, building codes in most jurisdictions
disallow negative pressures in residences. In a
home with a well-balanced air supply, the heat
exchanger should not be in danger of freezing.
Because the cause of back drafting is not considered
a manufacturing problem, any freezing damage
which occurs from back drafting will not be covered
by the Navien warranty. If there is any question
about the possibility of back drafting in the
installation location, use a direct venting system for
the boiler.
When using non-direct venting, maintain non-direct
vent clearances shown on page 64 as required by
ANSI Z21.10.3 and the National Fuel Gas Code,
ANSI Z223.1/NFPA 54, and CAN/CSA B149.1
Natural Gas And Propane Installation Code.