Tuesday, May 21, 2013

Bathroom Exhaust Fan Repair and Maintenance Guide

Posted at  10:38 AM - by maihoub ateya 16



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Bathroom Exhaust Fan Repair and 

Maintenance Guide

Does your bathroom exhaust fan squeal or squeak when you turn it on? Never fear, the problem is easy to fix. The bathroom exhaust fan is one of those over looked pieces of equipment that is frequently used, but infrequently maintained. In fact, most people do not even know that the exhaust fan needs maintenance. The bathroom fan is subjected to extreme moisture, and therefore collects dust. It is the combination of moisture, dust, and the heat generated by its operation, that takes its toll on this little electric fan motor. Indeed, it will take more time to read this article, than it takes to fix a squealing exhaust fan.
Caution: Before performing the steps below, make sure the switch that powers the fan is in the off position. If your exhaust fan is wired so that it comes on when you turn the bathroom lights on, then you will need to perform the removal steps using a flashlight, or other external light source. Because there are no exposed wires, the procedure can be done with power on, but it is best, and recommended, that the removal procedure only be performed with the power off.
Materials List
• 3 in 1 oil, or sewing machine oil
• Socket or wrench set
• Cleaning rag(s)
• Standard Pliers
• Regular screwdriver (flathead)
Step 1: Remove the Exhaust Fan Cover
Most bathroom exhaust fan covers have a small nylon bolt that fastens the cover to the fan assembly (see Photo 1). Carefully unscrew the nylon bolt. Note that the bolt is not made of metal, and can be deformed if you are too rough with it. Select a screwdriver whose tip is at least as wide as the nylon bolt. Using a screwdriver with a tip that too small for the nylon bolt head, may cause the slot to become deformed. While this will not affect the bolt's ability to fasten the cover, it will make the bolt look unsightly. Once the cover has been removed, you will notice dust on the underside of the cover, and on the fan assembly. This is common, regardless of how neat and tidy you are.
Step 2: Remove the Exhaust Fan Assembly
The exhaust fan receives its power through an outlet, similar to the standard electrical outlets found throughout the home (see Photo 2). After locating the outlet, simply unplug the cord. As you will note in Photo 3, the mounting screw is located in a slotted frame. Most exhaust fan assemblies will have three (3) screws evenly spaced around the frame. Loosen all three (3) of the mounting screws. They need to be loosened enough so that the fan assembly will rotate. The assembly is removed by rotating it until the screw heads are aligned with the large openings in the frame. Once the assembly has been removed, bring it to a table or bench for the fan disassembly procedure.
Step 3: Disassemble the Exhaust Fan Assembly
Support the blower wheel as shown in Photo 4. Gripping the fan assembly firmly, pull the blower wheel off the fan motor shaft. It too will need cleaning. Once the blower wheel is removed, take one of the cleaning rags and wipe the globs of dust from the exhaust fan assembly. You will note that there are two (2) bushing housings on the fan motor. One on each side of the stator windings. Mark each of the housings with matching marks on the stator windings as shown in Photo 5. The marks can be made with a marker, or by making scratches with the screwdriver. The point of marking is to ensure the housings are not switched or turned around when reassembling the fan motor. Remove the bushing housings by unscrewing the two (2) mounting bolts that hold the motor together. Lay the sub-assemblies out on a light colored piece of cloth like in This is a useful habit to get into, as it makes it easy to see the parts and sub-assemblies, and it allows you to keep the parts in the order in which they need to be assembled. The nuts to the far left of the photo are used to hold the fan motor to the exhaust fan frame.
Step 4: Lubricating the Bushing Housings
Using a cleaning rag, wipe any residual dust from the housings. Additionally, use the tip end of the rag to clean inside the brass sleeve that the motor shaft passes through. Just wedge the tip of the rag into the opening and twist it a few times. If the shaft was grungy , and the housing did not slide off easily, then you may need to use an oil soaked cotton swab to clean the brass sleeve. Photos and  show the bushing housings. Note that they are slightly different in construction. The construction of the housing(s) may vary. It would not be uncommon to find housings that are the same, or that are different from each other, as in this case. The tiny screwdriver is pointing to the area of the housing that requires oiling. Packed around the center brass sleeve is a material that absorbs and holds oil. Brass is a porous metal that allows the oil from the packing to flow through it. As the motor shaft spins inside the brass sleeve, it creates heat. The heat causes the brass to pull the oil from the packing, making it available to the spinning motor shaft as lubrication. Drip small amounts of oil on the packing material. Some puddling of the oil is common, just wait a bit, and allow the oil to soak into the packing material. Once the oil has soaked in, use a cleaning rag to wipe away any excess. The dirty shaft, as seen in can be cleaned by using a piece of notebook paper. Crumple the paper around the shaft and grip firmly with your fingers, twist the shaft within the paper using a "Back-and-Forth" motion.
Step 5: Reassembly
Reverse the procedure outlined in step 3 above. Ensure the bushing housings are positioned in their original locations by using the marks made above. Once the bolts have been screwed into the motor, tighten the motor to frame mounting nuts using the pliers. Take note of Photo 10. It shows a flat section of the motor shaft. This is important. Look into the hole in the center of the blower wheel and take note of the flattened part of the hole. The flattened part of the hole must match the flat section of the shaft. Once lined up, the blower wheel will side onto the shaft, and come to rest at its stop. If the blower is not sliding into place, then stop and ensure you have the flat ends aligned correctly. Never force the blower wheel onto the shaft. Most blower wheels are made of plastic, and rough handling will cause it to break. After the exhaust fan assembly has been completed, give the blower wheel a spin. It should now spin easily and freely. Reverse the procedures outlined in steps 2 and 1 above, and remount the fan assembly into the exhaust fan housing, and remount the exhaust fan cover. As stated before, be careful with the nylon bolt. Over tightening can cause the bolt to strip, and you will then need to purchase a new one.
The bathroom exhaust fan is a neglected piece of equipment that very rarely needs replacing. The type of motor used in the fan assembly is very hardy. Unless the stator windings have burned up, the only maintenance they need is cleaning and oiling. This is a tried and true procedure, and if used periodically for regular bathroom exhaust fan maintenance, the life of the bathroom fan can be extended indefinitely. In fact, the photos were taken from an exhaust fan that has been in use since 1981. This (original) bathroom fan has been in use for twenty (20) years, and has been oiled five (5) times.

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