Removing a tired Broan 678 bathroom fan is often the first step to a quieter, more efficient bathroom ventilation system. This specific model, while reliable in its time, can develop worn-out ball bearings or crack under the heat and moisture of daily use. Replacing it with a modern unit not only reduces noise but also improves airflow, ensuring your bathroom stays dry and mold-free.
Confirming Your Fan is a Broan 678
Before you begin the replacement, it is essential to verify you are indeed dealing with a Broan 678. Look for the model number printed directly on the front of the housing, typically on a silver or white sticker. The 678 is a popular 6-inch ceiling fan, so you will also want to measure the diameter of your current unit to ensure compatibility with standard baffles. If the housing is damaged or the label is illegible, simply measure the cutout hole in your ceiling to confirm it matches the 6-inch standard dimension.
Safety and Preparation
Safety is paramount when working with electrical fixtures located directly overhead. Start by turning off the power to the bathroom at the main circuit breaker; do not rely solely on the wall switch. Use a non-contact voltage tester to double-check that the wires are dead before touching them. Gather your tools, which will likely include a screwdriver, wire nuts, electrical tape, and a sturdy stepladder. If your new fan does not come with a new mounting bracket, you may need to purchase one separately to align the airflow correctly.
Removing the Old Broan 678 Fan
Once the power is off, position your ladder securely and remove the decorative front cover of the Broan 678. Usually, this cover is held on by clips or small screws. With the cover removed, you will see the fan motor and the wiring connections. Carefully disconnect the electrical wires, taking note of how they are attached—taking a photo with your phone is a good habit. Finally, unfasten the brackets or screws holding the motor housing to the ceiling joists and gently lower the heavy unit out of the hole.
Inspecting the Ductwork
With the old fan removed, take a moment to inspect the duct line running to the exterior. Bathroom fans need a clear, smooth path to expel moisture effectively. If the old duct is flexible plastic kinked or crushed, now is the time to replace it with rigid metal ducting. A well-sealed duct prevents warm air from escaping into the attic and reduces the risk of condensation build-up, which can lead to structural damage over time.
Installing the New Replacement Fan
With the wiring hanging through the hole, secure the new fan's mounting bracket to the ceiling joists if required. Most modern units come with a hook and quick-connect system that simplifies hanging the motor. Carefully thread the electrical wires through the collar, connect the wires according to the color-coded diagram (usually black to black, white to white, and green/bare to ground), and secure them with waterproof wire nuts. Ensure the connections are tight and insulated with electrical tape to prevent future shorts.
Balancing the Fan Blades
Once the motor is secured to the bracket, attach the fan blades and the front grill. Many homeowners overlook the importance of balance; if the blades are slightly uneven, they can wobble and create a humming resonance. After assembly, turn the power back on at the breaker and test the fan. If you notice vibration, power off the unit, and slightly adjust the wing nuts on the brackets or ensure all blades are aligned evenly. Modern fans often include an LED light; verify that the illumination works correctly as well.
Final Testing and Performance Check
After the physical installation is complete, perform a final operational test. Turn the fan on high and place a tissue over the exterior vent hole to confirm that air is being expelled outside. If the air is simply circulating inside the attic, you have a ducting issue. Additionally, check the fan's CFM (Cubic Feet per Minute) rating; a higher CFM ensures the bathroom clears steam quickly. With the Broan 678 replaced, you should enjoy a quieter operation and a bathroom that stays fresh much longer.
