3General venting (continued)
The Knight XL uses model specific combustion air intake and vent piping sizes as detailed in Table 3D below.
Installation & Operation Manual
Vent and air piping
Vent and air system:
Model | Air Intake | Vent |
|
|
|
399 - 600 | 4 inches (102 mm) | 4 inches (102 mm) |
|
|
|
700 - 800 | 4 inches (102 mm) | 6 inches (152 mm) |
NOTICE
Installation must comply with local requirements and with the National Fuel Gas Code, ANSI Z223.1 for U.S. installations or CSA B149.1 for Canadian installations.
NOTICE | Increasing or decreasing combustion air | |
or vent piping is not authorized. | ||
|
Minimum / Maximum allowable combustion air and vent piping lengths are as follows:
You must also install air piping from outside to the boiler air intake adapter. The resultant installation is direct vent (sealed combustion).
You may use any of the vent/air piping methods covered in this manual. Do not attempt to install the Knight XL using any other means.
Combustion Air = 12 equivalent feet (3.7 m) minimum / 100 equivalent feet (30.5 m) maximum
Vent = 12 equivalent feet (3.7 m) minimum / 100 equivalent feet (30.5 m) maximum
When determining equivalent combustion air and vent length, add 5 feet (1.5m) for each 90° elbow and 3 feet (.9 m)
WARNING
DO NOT mix components from different systems. The vent system could fail, causing leakage of flue products into the living space. Use only approved stainless steel, PVC or CPVC pipe and fittings. For PVC/CPVC use with primer and cement specifically designed for the material used.
for each 45° elbow.
EXAMPLE: 20 feet (6 m) of PVC pipe + (3) 90° elbows + (3) 45° elbows + (1) concentric vent kit (CVK3007) = 49 equivalent feet (15 m) of piping.
NOTICE | The appliance output rating will reduce by | |
up to 1.5% for each 25 feet (68 m) of vent | ||
|
Vent, air piping and termination:
The Knight XL vent and air piping can be installed through the roof or through a sidewall. Follow the procedures in this manual for the method chosen. Refer to the information in this manual to determine acceptable vent and air piping length.
Optional room air
length. |
Table 3E Concentric Vent Kit Equivalent Vent Lengths |
NOTICE
Optional room air is intended for commercial applications. Combustion air piping to the outside is recommended for residential applications.
Model | Kit Number | Equivalent | |
Vent Length | |||
|
| ||
399 | CVK3007 | 5 Feet (1.5 m) | |
|
|
| |
500 | CVK3007 | 30 Feet (9 m) | |
|
|
| |
600 | CVK3007 | 30 Feet (9 m) | |
|
|
|
Removing from existing vent
Follow the instructions in Section 1, page 12 of this manual when removing a boiler from an existing vent system.
Commercial applications utilizing the Knight XL boiler may be installed with a single pipe carrying the flue products to the outside while using combustion air from the equipment room. In order to use the room air venting option the following conditions and considerations must be followed.
•The unit MUST be installed with the appropriate room air kit (Table 3F).
•The equipment room MUST be provided with properly sized openings to assure adequate combustion air. Please refer to instructions provided with the room air kit.
•There will be a noticeable increase in the noise level during normal operation from the inlet air opening.
•Using the room air kit makes the unit vulnerable to combustion air contamination from within the building. Please review Section 1, Prevent Combustion Air Contamination, to ensure proper installation.
•Vent system and terminations must comply with the standard venting instructions set forth in this manual.
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