Vermont Casting Vermont Castings Jefferson Vent Free Gas Heater, W A R N I N G, Gas Water Heater

Vermont Castings Jefferson Vent Free Gas Heater

2.Divide the volume of space by 50 cubic feet. The result is the maximum BTU/hour the space can support.

Example: 3840 cubic feet divided by 50 = 76.8 or 76,800 BTU/hour.

3.Add the BTU/hour ratings of all fuel-burning appli- ances installed in the same space, including the following:

Gas Water Heater	Gas Furnace
Gas Fireplace Logs	Vent-free Gas Heater
Vented Gas Heater*	Other Gas Appliances*

*Do not include Direct-vent appliances as these use outdoor air for combustion and vent to the outdoors.

Example:
Gas Range	55,000 BTU/hour
Vent-free Logset	+25,000 BTU/hour
Total	80,000 BTU/hour

4.Compare the maximum BTU/hour rating the space can support with the total BTU/hour used by the appli- ances.

Example: 76,800 BTU/hour the space can support 80,000 BTU/hour used by appliances

In this example, the maximum BTU/hour that the space can support is less than the total used by the appli- ances. The space is considered to be Confined Space.

Additional air must be provided to meet the require- ments of the vent-free heater.

A confined space may be ventilated in two ways:

A. Open or provide at least two ventilating grilles to an adjoining unconfined space. (Fig. 3)

Each of the two grilles must provide an opening of at least 50 square inches, with all opening dimensions being at least 3”. One grille must be within 12” of the ceiling; the other within 12” of the floor. (If the total exceeds 100,000 BTU/hour, additional grilles will be needed.)

B. Vent the room directly to the outdoors. (Provide one square inch of opening for each 4,000 BTU/hour)

For further information on ventilation guidelines and sizing specifications, follow the National Fuel Gas Code/NFPA 54/ANSI Z223.1, Section 5.3.

If the total BTU/hour used by the appliances is less than the maximum BTU/hr the space can support, the room meets the Unconfined Space criteria and no further ventilation is needed.

W A R N I N G

This heater shall not be installed in a confined space unless provisions are made for adequate combustion and ventilation air.

W A R N I N G

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, 1992 Section 5.3.

Option 1 -

Vents to

Adjoining

RoomsOption 3 -

Vents to

Adjoining

Room

Option 2 -

Remove Door to

Adjoining Room

VO370-2

Fig. 3 Supplementing ventilation air.

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