Remove housings that enclose gears, and clean the gears thoroughly with kerosene. Grit in the gears will cause undue wear. Be extra careful that the fan motor, electric ignition system, and wiring are completely clean and dry before you turn on the electricity. Electric motor cleaning should be left to electricians and repairpeople. Check any chimney that has been in contact with water for leaks that may have developed from dissolved mortar.
Most chimneys have a foundation in the ground.
Check the foundation, and make sure it has not been undermined. Follow the instructions furnished. After lighting the candle, trap the smoke in the chimney by restricting the top of the chimney. Leave a small opening so the smoke will rise. Smoke escaping through the masonry will indicate leaks you may not see otherwise.