CAZ, this can be difficult to diagnose at first because when entering the CAZ, the open door allows the pressure to equalize, supplying fresh air to the room. This temporarily fixes the problem. Look for clues that the burner was starved for air when the problem occurred. Some hints that there are air supply problems include: • Odors or smoke in the building when the unit runs • Carbon monoxide detector sounds alarm • Soot or rust on top of unit, in burner air tube, and draft regulator • Burner rumbles • Soot streaks around inspection port • Sooted-up cad cell and drawer assembly A carbon monoxide problem in the building is caused by improper combustion and a venting failure. Ambient CO BPI certified contractors training states that when running combustion appliances for testing, the technician should monitor the ambient CO levels in the room in which they are working. If at any point the CO level in the room goes above 35 ppm, they are to turn off the appliances, open the doors and windows to provide fresh air and go outside until the CO drops to a safe level before returning to the CAZ. They are to inform the customer a heating technician must inspect and repair the system. Carbon Monoxide Remedies • Do NOT use unvented combustion appliances. 42 National Oilheat Research Alliance • Inspect and tune-up combustion appliances. • Be sure all venting systems are operating properly. • Be sure there are no holes in furnace heat exchangers or leaks in returns in the combustion air zone. • Install a carbon monoxide detector on each floor. • Bring in combustion air from outdoors. Spillage (Back Draft) Test Spillage occurs when proper negative draft is not established in the venting system and flue gases spill from the appliance into the building. Spillage often leaves behind visual signs—rust and soot on top of the unit and on the floor around the unit. To check for spillage, turn the unit on and use the back of your hand or a smoke stick. Check airflow around the draft diverter or draft regulator to be sure that within one minute of firing, the flow is from the building into the venting system. For induced draft heating units, check for spillage at the base of the chimney. Figure 1 on following page. Spillage that occurs under normal building operating conditions should be addressed immediately. Spillage should also be checked under simulated worst-case conditions. Draft Test Take a pressure measurement in the flue pipe with reference to the combustion appliance zone. Draft should be measured in a hole in the flue pipe 12" from the draft diverter for gas
NORA Advanced Efficiency
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