If you are not totally sure of this procedure, consult a :
UPFLOW FURNACE – FILTERS IN BOTTOM OR SIDE DUCT LOCATION
DOWNFLOW FURNACE – FILTERS IN TOP DUCT LOCATION
Routine maintenance to be provided by a qualified installer, service agency or the gas supplier ONLY.
The blower motor and induced draft motor are prelubricated by the manufacturer and do not require further attention
IMPORTANT: DO NOT attempt to lubricate the bearings on the blower motor or the induced draft blower motor. Addition of lubri- cants can reduce the motor life and void the warranty
WARNING: DISCONNECT MAIN ELECTRICAL POWER TO THE UNIT BEFORE ATTEMPTING ANY MAINTENANCE. FAILURE TO DO SO CAN RESULT IN ELECTRICAL SHOCK, SEVERE PERSONAL INJURY OR DEATH.
The blower compartment and motor should be inspected and cleaned periodically by your qualified installer, service agency or the gas supplier to prevent the possibility of overheating due to an accumulation of dust and dirt on the windings or on the motor
COMBUSTION AREA AND VENT SYSTEM
WARNING: IF DIRT, RUST, SOOT OR SCALE ACCUMULATIONS ARE PRESENT, DO NOT OPERATE THE FURNACE. INSPECT THE HEAT EXCHANGERS FOR LEAKS. LEAKS CAN CAUSE TOXIC FUMES TO ENTER THE HOME AND CAUSE CARBON MONOXIDE POISONING OR DEATH.
WARNING: CHECK VENT PIPE SECTIONS FOR DETERIORATION AND CHECK JOINT FITTINGS FOR THEIR INTEGRITY. IF IT HAS BECOME DISCONNECTED OR TOXIC FUMES CAN ESCAPE INTO THE HOME AND CAUSE CARBON MONOX- IDE POISONING OR DEATH. DO NOT OPERATE THIS FURNACE. APPROPRIAT
NOTE: This furnace is equipped with a pressure switch which will shut off the main burners if the condensate drain line becomes blocked.