Desa GVB50N, GVB35N installation manual Combustion, Ventilation, Fresh Air For, Continued

FRESH AIR FOR	DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION
COMBUSTION	Example 1: Locating Heater in Unconfined (Open) Area
AND		NOTICE
VENTILATION		An unconfined area has a minimum air volume of 50
Continued		cubic feet for each 1000 BTU/Hr input rating of all
		appliances in the area (cubic feet equals length x width
		x height of area). Include adjoining rooms only if there
		are no doors between the rooms or if you add ventila-
		tion grills between the rooms (see Ventilating Confined
		Area, page 19).
	In an open area, the air that leaks around doors and windows may provide enough
	fresh air for combustion and ventilation.

Draft Hood Spillage Test

Follow the steps below to see if enough fresh air is available.

1.Close all windows and doors.

2.If you have a fireplace, start a fire. Build fire until flames are burning strongly.

3.Turn on all exhaust fans. These include exhaust fans for kitchen, bathroom, water heaters (gas or electric), etc.

4.Turn on all vented gas appliances. These include any room heaters, water heaters, clothes dryer, etc.

5.Wait ten minutes for drafts to regulate.

6.Check for draft-hood spillage at each vented gas appliance. Do this by holding a lit match two inches from the draft opening (see Figure 13). If match flame pulls toward the draft hood, there is no spillage. If match flame blows away from the draft hood, there is spillage. This is a hazardous condition. See Draft Hood Spillage, page 18.

	Vent Pipe
Vent Pipe
Draft Hood
Match	Heater
Typical	Match
Water
Heater	Draft Hood
	Opening

Figure 13 - Checking for Draft Spillage

No Draft Hood Spillage: This shows there is enough fresh air in area for appliances. Turn off all exhaust fans and appliances if desired.

Continued 17

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