7COMBUSTION AREA ANDVENT SYSTEMInspect the combustion area and vent system before eachheating season. An accumulation of dirt, soot, or rust canmean a loss of efficiency and improper performance. Build-ups on the main burners can cause faulty firing. This “delayedignition’’ is characterized by an alarmingly loud sound. Ifyour furnace makes a loud noise when the main burners areignited, shut down the furnace and call your servicing dealer.Use your flashlight and follow these steps for inspecting thecombustion area and vent system of your furnace:1. Turn off the gas and electrical supplies to the furnace andremove the access doors. (See Fig. 7 and 8.)2. Carefully inspect the gas burner (see Fig. 23) for dirt, rust,or scale. Then inspect the inducer, vent connection area,and the vent pipe for rust.22NOTE: If dirt, rust, soot, or scale accumulations are found, callyour servicing dealer. DO NOT OPERATE THE FURNACE.3. Inspect the vent pipe for a sag, holes, or a disconnection.A horizontal vent pipe must slope upward away from thefurnace. If rusty joints or seams, or signs of water leakag-es are found, call your dealer for service.4. Replace the access doors and restore gas and electricalsupplies to the furnace. Be sure bottom door flange isinside of the furnace casing. (See Fig. 13, 14, 15 and 22.)5. Start the furnace and observe its operation. If possible,watch the burner flames. Are they burning bright blue?If not (or if you suspect some other malfunction), callyour servicing dealer.232425CAUTIONUse care when cutting support rods in filters toprotect against flying pieces and sharp rod ends.Wear safety glasses, gloves, and appropriate pro-tective clothing. Failure to follow this cautioncould result in personal injury.WARNINGIf holes caused by deterioration are found—orholes in the vent pipe—or if the vent pipe is ob-structed or is not connected—toxic fumes can es-cape into your home. DO NOT OPERATE YOURFURNACE. Call your dealer for service. A failure tofollow this warning could result in personal injuryor death.!!