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D.5.2 Test for Combustion Air and Vent Drafting for Natural Draft and Category I Appliances
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Combustion air and vent draft procedures are for natural draft and category I appliances equipped with a draft hood and connected to a natural draft venting system.
- Preparing for Inspection. Close all exterior building doors and windows and all interior doors between the space in which the appliance is located and other spaces of the building that can be closed. Turn on any clothes dryer. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan. Close fireplace dampers and any fireplace doors.
- Placing the Appliance in Operation. Place the appliance being inspected in operation. Adjust the thermostat or control so the appliance will operate continuously.
- Spillage Test. Verify that all appliances located within the same room are in their standby mode and ready for operation. Follow lighting instructions for each appliance as necessary. Test for spillage at the draft hood relief opening as follows:
- After 5 minutes of main burner operation, check for spillage using smoke.
- Immediately after the first check, tum on all other fuel gas burning appliances within the same room so they will operate at their full inputs and repeat the spillage test.
- Shut down all appliances to their standby mode and wait for 15 minutes.
- Repeat the spillage test steps a through c on each appliance being inspected.
- Additional Spillage Tests: Determine if the appliance venting is impacted by other door and air handler settings by performing the following tests.
- Set initial test condition in accordance with D.5.2 (1).
- Place the appliance(s) being inspected in operation. Adjust the thermostat or control so the appliance(s) will operate continuously.
- Open the door between the space in which the appliance(s) is located and the rest of the building. After 5 minutes of main burner operation, check for spillage at each appliance using smoke.
- Turn on any other central heating or cooling air handler fan that is located outside of the area where the appliances are being inspected. After 5 minutes of main burner operation, check for spillage at each appliance using smoke. The test should be conducted with the door between the space in which the appliance(s) is located and the rest of the building in the open and in the closed position.
- Return doors, windows, exhaust fans, fireplace dampers, and any other fuel gas burning appliance to their previous conditions of use.
- If, after completing the spillage test it is believed sufficient combustion air is not available, the owner should be notified that an alternative combustion air source is needed in accordance with Section G2407 of the International Fuel Gas Code. Where it is believed that the venting system does not provide adequate natural draft, the owner should be notified that alternative vent sizing, design or configuration is needed in accordance with Chapter 24 of the International Fuel Gas Code. If spillage occurs, the owner should be notified as to its cause, be instructed as to which position of the door (open or closed) would lessen its impact, and that corrective action by a HV AC professional should be taken.