PROVISIONS FOR ADEQUATE COMBUSTION & VENTILATION AIR
This heater shall not be installed in a confined space unless provisions are provided for adequate combustion and ventilation air.
The National Fuel Gas Code defines a confined space as a space whose volume is less than 50 cubic feet per 1,000 Btu per hour (4.8m3 per kw) of the aggregate input rating of all appliances installed in that space and an unconfined space as a space whose volume is not less than 50 cubic feet per 1,000 Btu per hour (4.8 m3 per kw) of the aggregate input rating of all appliances installed in that space. Rooms communicating directly with the space in which the appliances are installed, through openings not furnished with doors, are considered a part of the unconfined space.
Unusually Tight Construction
The air that leaks around doors and windows may provide enough fresh air for combustion and ventilation. However, in buildings of unusually tight construction, you must provide additional fresh air.
Unusually tight construction is defined as construction where:
a.Walls and ceilings exposed to the outside atmosphere have a con- tinuous water vapor retarder with a rating of one perm or less with openings gasketed or sealed, and
b.
c.Caulking or sealants are applied to areas such as joints around window and door frames, between sole plates and floors, between
If your home meets all of the three criteria above, you must provide additional fresh air.
Warning: If the area in which the heater may be operated is smaller than that defined as an unconfined space or if the building is of unusually tight construction, provide adequate combustion and ventilation air by one of the methods described in the National Fuel Gas Code, ANSI Z223.1, Section 5.3. or applicable local codes.
Example of Large Room with 1/2 Wall divider.
Figure 1
The following formula can be used to determine the maximum heater rating per the definition of unconfined space:
Btu/Hr = | (L1 | + L2)FT x (W)FT x (H)FT | x 1000 |
|
|
50
If the area in which the heater may be operated is smaller than that defined as an unconfined space, provide adequate combustion and ventilation air by one of the methods described in the National Fuel Gas Code, ANSI Z223.1, Section 5.3.
Adhere to all codes, or in their absence, the latest edition of THE NATIONAL FUEL GAS CODE ANSI Z223.1 or NFPA54 which can be obtained from:
American National Standards Institute
11 West 42nd St.
New York, NY 10018
OR
National Fire Protection Association, Inc.
Batterymarch Park
Quincy, MA 02269
CLEARANCES
Minimum Dimensions For Solid Fuel Burning Fireplaces UL127 Factory Built Fireplaces (Figure 2)
Model | A | B | C | D |
VFDR18LB10 | 17" | 12" | 28" | 17" |
VFD(R,T,M)18 | 17" | 12" | 28" | 17" |
VFD(R,T,M)24 | 23" | 12" | 30" | 18" |
VFD(R,T,M)30 | 26" | 12" | 34" | 20" |
The dimensions shown and defined in the fireplace manufacturer’s instructions are minimum clearances to maintain in installing this heater. Left and right clearances are determined when facing the front of the heater.
Glass Doors
Make sure that glass doors are open during all operations of the logset. The opening of the glass door frame should be the dimension used for the minimum front opening of the firebox.
Figure 2
Follow these instructions to ensure safe installation.
Failure to follow instructions exactly can create a fire hazard.
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