Installation & Operation Manual
3
General venting
16
Air intake/vent connections
1.
Combustion Air Intake Connector
(FIG.’s 20 and 21) -
Used to provide combustion air directly to the unit
from outdoors. A fitting is provided on the unit for final
connection. Combustion air piping must be supported
per guidelines listed in the National Mechanical Code,
Section 305, Table 305.4 or as local codes dictate.
2.
Vent Connector
(FIG.’s 20 and 21) - Used to provide a
passageway for conveying combustion gases to the
outside. A transition fitting is provided on the unit for
final connection. Vent piping must be supported per the
National Building Code, Section 305, Table 305.4 or as
local codes dictate.
Combustion air piping to the outside
MUST BE used. Use of combustion air
from the room via louvers, plenums, or
any other device is not authorized.
NOTICE
Figure 20
Near Boiler Venting Models 80 - 210
Figure 21
Near Boiler Venting Models 285 - 500
Maximum allowable combustion air and
vent piping lengths are as follows:
Combustion Air
= 100 equivalent feet
Vent
= 100 equivalent feet
When determining equivalent combustion air and vent
length, add 5 feet for each 90° elbow, 3 feet for each 45° elbow,
and 3 feet for the concentric vent kit, see example below.
EXAMPLE:
20 feet of PVC pipe + (4) 90° (2) 45°
(1) concentric vent kit = 49 equivalent feet of
piping.
The Knight boiler uses model specific combustion air intake
and vent piping sizes as detailed in Table 4 below.
Model
Air Intake
Vent
80 - 210
3"
3"
285 - 500
4"
4"
Table 4
Air Intake/Vent Piping Sizes
Increasing or decreasing combustion air
or vent piping is not authorized.
NOTICE
