3FURNACE COMPONENTSBurner sight glass for viewing burner flame.Burner assembly (inside). Operates with energy-savinginshot burners, and hot surface igniter for safe,dependable heating.Combustion-air intake connection (right or left side).Redundant gas valve. Safe, efficient. Features 1 gas con-trol with 2 internal shutoff valves.Junction box for 115-v electrical power supply.Vent outlet. Uses PVC pipe to carry flue gas from the fur-nace’s combustion system (right or left side).Secondary condensing heat exchanger (inside). Wringsout more heat through condensation. Constructed withpolypropylene-laminated steel to ensure durability.Pressure switch. Ensures adequate flow of flue gasthrough furnace and out vent system.Inducer motor. Pulls hot flue gases through the heat ex-changers, maintaining negative pressure for added safety.Condensate drain connection. Collects moisture con-densed from burned gases for disposal into home drainsystem. (location in furnace varies)123456789102MODEL 58MSA FURNACE(SHOWN IN UPFLOW POSITION)Heavy-duty blower. Circulates air across the heat ex-changers to transfer heat into the home.Air filter and retainer.Rollout switch (manual reset) to prevent overtemperature.Primary serpentine heat exchanger (inside). Stretches fueldollars with the S-shaped heat-flow design. Solid con-struction of corrosion-resistant aluminized steel means re-liability.3-amp fuse provides electrical and component protection.Light emitting diode (LED) on furnace control board.Code light is for diagnosing furnace operation and servicerequirements.Furnace Control board.Blower access panel safety interlock switch.Transformer (24v) behind furance control board provideslow-voltage power to furnace control board and thermo-stat.111213141516171819121168109764512131418315161719