Navien NFB Series, Руководство по установке и эксплуатации

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53 Venting the Boiler
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"
2. Provide two openings to allow for circulation of combustion air
as specified by ANSI Z223.1/NFPA 54 or CAN/CGA B-149.1:
NFB-175 NFB-200
Maximum Input (BTU/H) 175,000 199,000
Outdoor make up air is
provided, a minimum
free area of 1 in
2
, per
4,000 BTU/H
44 in
2
10 in (W) x
5 in (H) or
8 in round
50 in
2
10 in (W) x
5 in (H) or
8 in round
Indoor make up air is
provided, a minimum
free area of 1 in
2
per
1,000 BTU/H
175 in
2
13 /4 in (W) x
13 /4 in (H)
199 in
2
14 /4 in (W) x
14 /4 in (H)
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 54 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.
Ref Description Canadian Direct Vent Installations
1
US Direct Vent Installations
2
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.