For window air conditioners, never use extension cords! Lubricate belt drive pulleys (where applicable), boss bearings on drive motors, and other equipment as needed. Have the resistance coils or furnace burners cleaned and serviced at the beginning of the heating season, since debris may accumulate there while the system is off during the summer. Listen to the system when it is operating. Squealing sounds, rumbling noises, or banging and tapping sounds may indicate loose parts or bearings which are seizing up. If you have access to a snap-on amp meter, you may check the amperage draw on the high amperage circuit to your heating coils to make sure they are in the normal operating range. Higher than normal amperage draw on a circuit indicates unusual resistance, and in an electrical circuit, resistance is what causes heat, and ultimately, fires.
