Desa Tech CGD3924PT, CGD3930PT installation manual Air For Combustion And Ventilation, Continued

AIR FOR

COMBUSTION AND

VENTILATION

Continued

DETERMINING AIR FLOW FOR HEATER LOCATION

Determining if You Have a Confined or Unconfined Space-

Use this work sheet to determine if you have a confined or unconfined space.

Space: Includes the room in which you will install heater plus any adjoining rooms with

doorless passageways or ventilation grills between the rooms.

1. Determine the volume of the space (length x width x height).

Length x Width x Height		=	cu. ft. (volume of space)
Example:	Space size	20 ft. (length) x 16 ft. (width)	x 8 ft. (ceiling height) =
		2560 cu. ft. (volume of space)

If additional ventilation to adjoining room is supplied with grills or openings, add the volume of these rooms to the total volume of the space.

2.Divide the space volume by 50 cubic feet to determine the maximum Btu/Hr the space can support.

(volume of space) + 50 cu. ft. = (Maximum Btu/Hr the space can support)

Example: 2560 cu. ft. (volume of space) + 50 cu. ft. = 51.2 or 51,200 (maximum Btu/Hr the space can support)

3. Add the Btu/Hr of an fuel burning appliances in the space.
	Vent-free	heater			Btu/Hr
	Gas water	heater*			Btu/Hr
	Gas furnace				Btu/Hr
	Vented gas heater				Btu/Hr
	Gas fireplace logs				Btu/Hr
	Other gas appliances*		+		.Btu/Hr
	Total		=		Btu/Hr
Example:	Gas water	heater		40,000	Btu/Hr
	Vent-free	heater	+	39,000	Btu/Hr
	Total		=	79,000	Btu/Hr

*Do not include direct-vent gas appliances. Direct-vent draws combustion air from the outdoors and vents to the outdoors.

4.Compare the maximum Btu/Hr the space can support with the actual amount of Btu/Hr used.

Btu/Hr (maximum the space can support)

Btu/Hr (actual amount of Btu/Hr used)

Example: 51,200 Btu/T-Ir(maximum the spacecan support) 79,000 Btu/Hr (actualamount of BtuiHr used)

The space in the above example is a confined space because the actual Btu/Hr used is more than the maximum Btu/Hr the space can support. You must provide additional fresh air.

Your options are as follows:

A.Rework wurksheet, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adjoining room or add ventilation grills between rooms. See Ventilation Air From Inside Building, page 7.

B.Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 7. C. Install a lower Btu/Hr heatar, if lowar Btu/Hr size makes room unconfined.

Iftbe actual Btu/Hr used is less than the maximum Btu/I-Irthespace can support, the space is an unconfined space. You will need no additional fresh air ventilation.