Desa CGR50NA, CGR35NA Air For Combustion And Ventilation, Continued, Draft Hood Spillage Test

AIR FOR COMBUSTION AND VENTILATION

Continued

In the absence of local codes, use the following excerpts from the National Fuel

Gas Code NFPA 54/ANSI Z223.1, Air for Combustion and Ventilation.

DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION

Example 1: Locating Heater in Unconfined (Open) Area

NOTICE

An unconfined area has a minimum air volume of 50 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 20).

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 14). 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 19.

Vent Pipe

Draft Hood

Match

Typical

Water

Heater

Vent Pipe

Heater

Match

Draft Hood

Opening

18

Figure 14 - 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.

100792