(4) Height Beneath Blades
- Now, check the floor-to-ceiling height of the fan blades. You can do this by measuring the floor-to-ceiling distance and subtracting for the part of the fan that will extend below the ceiling down to the lower blade surface. An absolute minimum height of 7' is recommended (Fig. 7). This may be reinforced by building codes in your area.
- If the floor-to-ceiling distance is too little, check into a low-ceiling mount for your fan. With some models, the fan blade height can be increased by as much as 10". Remember, though, that you need at least 12" between the ceiling and the tops of the fan blades for proper airflow (Fig. 7). Having 18" is better if the space is available.
(5) Mounting the Fan to the Box
- Install the hanger bracket on the box with screws and lock washers. If no lock washers are supplied, get some - they prevent fan vibration from loosening the screws over time.
- The hanger bracket may accept either a half-ball hanger or a hook-type hanger, depending on which kind your fan uses. Either way, the hanger is carefully slipped into the bracket.
- Next, the unit is wired, and the ceiling cover is slipped up to its full height and tightened in place.
- Be sure to connect the black house wires to the black fan wires, and the white house wires to the white fan wires.
- The fan should be electrically grounded to both the metal box and the fan. The grounding wires will be either green or bare copper. A green grounding pigtail attached to the box by a bonding screw will make your work easier. Wirenut the ground wires from the box, the fan and the power supply together.
- If the fan wobbles when it runs, its blades may be unbalanced. To correct this, try interchanging two adjacent blades. If that doesn't work, take all the blades off and weigh each one on a food or postal scale. If any is underweight, tape a soft object such as a pencil eraser or modeling clay to the top center of the blade, making its weight the same as the others. Reinstall the blades and the fan should run smoothly.
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