Installation & Operation Manual
2 General venting (continued)
Table 2B Direct Vent Minimum / Maximum Allowable Air / Vent Lengths
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| AIR INLET |
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| VENT |
| Input |
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Model | Air Intake | Air Intake | Air Intake | Vent | Vent | Vent | |
| Diameter | Min. Length | Max. Length | Diameter | Min. Length | Max. Length | 25 feet of Vent |
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FB 1500 | 7" | 12' | 100' | 7" | 12' | 100' | 2% |
FB 2000 | 8" | 12' | 100' | 8" | 12' | 100' | 2% |
FB 2500 | 8" | 12' | 100' | 9" | 12' | 100' | 2% |
FB 3000 | 10" | 12' | 100' | 10" | 12' | 100' | 2% |
FB 3500 | 10" | 12' | 100' | 10" | 12' | 100' | 2% |
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Table 2C Room Air Minimum / Maximum Allowable Air / Vent Lengths
Model | Vent | Vent | Vent | Input | |
Diameter | Min. Length | Max. Length | 25 feet of Vent | ||
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FB 1500 | 7" | 12' | 100' | 1% | |
FB 2000 | 8" | 12' | 100' | 1% | |
FB 2500 | 9" | 12' | 100' | 1% | |
FB 3000 | 10" | 12' | 100' | 1% | |
FB 3500 | 10" | 12' | 100' | 1% |
When determining equivalent combustion air and vent length, add 5 feet (1.5m) for each 90° elbow and 3 feet (.9 m) for each 45° elbow.
EXAMPLE: 20 feet (6 m) of pipe + (4) 90° elbows + (3) 45° elbows = 49 equivalent feet (15 m) of piping.
Removing from existing vent
Follow the instructions in Section 1, page 10 of this manual when removing a boiler from an existing vent system.
Vent and air piping
Vent and air system:
Installation must comply with local NOTICE requirements and with the National Fuel
Gas Code, NFPA 54 / ANSI Z223.1 for U.S. installations or CSA B149.1 for Canadian installations.
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 Crest using any other means.
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 pipe and fittings.
Vent, air piping and termination:
The Crest 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.
Air contamination
Pool and laundry products and common household and hobby products often contain fluorine or chlorine compounds. When these chemicals pass through the boiler, they can form strong acids. The acid can eat through the boiler wall, causing serious damage and presenting a possible threat of flue gas spillage or boiler water leakage into the building.
Please read the information given in Table 1A, page 9, listing contaminants and areas likely to contain them. If contaminating chemicals will be present near the location of the boiler combustion air inlet, have your installer pipe the boiler combustion air and vent to another location, per this manual.
If the boiler combustion air inlet is located WARNING in a laundry room or pool facility, for
example, these areas will always contain hazardous contaminants.
To prevent the potential of severe personal WARNING injury or death, check for areas and products
listed in Table 1A, page 9 before installing the boiler or air inlet piping.
If contaminants are found, you MUST:
•Remove products permanently.
•Relocate air inlet and vent terminations to other areas.
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