Desa Tech CGN30TL, CGN20TL installation manual Fresh Air, Ventilation, Combustion, Continued

FRESH AIR	DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION
FOR	Determining if You Have a Confined or Unconfined Space
	Use this worksheet to determine if you have a confined or unconfined space.
COMBUSTION
	Space: Includes the room in which you will install heater plus any adjoining rooms
AND	with doorless passageways or ventilation grills between the rooms.
VENTILATION	1. Determine the volume of the space (length x width x height).
Continued	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 all 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	+	20,000		Btu/Hr
		Total	=	60,000		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/Hr (maximum the space can support)
60,000	Btu/Hr (actual amount of Btu/Hr 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 worksheet, 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 8.

C.Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined.

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

6

103873