Adjustments made to the belt that drives the blower of a forced hot air furnace system can improve the performance of heat distribution throughout the entire house. If you will take just a few minutes time to perform the maintenance, you can provide your house with a much more efficient heating system than you have right now.
The first thing to do is check the condition of the furnace’s blower belt. Look for tell-tale signs of wear and tear. A frayed belt or one that is old and rigid needs to be replaced. You can replace the belt at any of the major home improvement stores like the Lowe’s or the Home Depot, but you should really consider visiting a locally owned and operated hardware or HVAC supply store. If there are any left in your community, that is. Take the old belt with you wherever you plan to shop for your new belt so that you make sure you will get the exact size belt you need.
If the belt on your furnace blower is not frayed or in bad condition, there are still some things going on in there that can result in a reduction of efficiency resulting in your house not receiving the full amount of heat to which it is entitled and for which you are paying a premium for. Test the tension of the forced air furnace’s blower belt. A blower belt that is perfectly tensioned will deflect only about ¾th of an inch when you press down on it. A blower belt that moves less than that needs to be adjusted so that it you aren’t putting undo pressure upon it that will lead to premature aging and replacement. Locate the blower’s adjustment bolt and vary the distance between the motor and the blower drum until you achieve proper tension.
Take a look at all the blots that hold the furnace blower motor to its mount. As with most bolts, these should be wound up tighter than a Ritalin addict on the day before he can renew his prescription. Take a look at the pulleys and make sure they are aligned. You can check for pulley alignment by using a simple carpenter’s square. Place one leg across the body of the motor and the other across the pulleys. Ideally, both pulleys will be touching the blade. If this is not the case, loosen the bolts and slide the motor over until the pulleys are properly aligned and then make sure that you do have bolts on them as tight as what I compared them to up there when I was kissing to be clever.
Finally, you may need to increase the motor speed. This can be accomplished by using an Allen wrench to adjust the setscrew that holds the outer pulley to the motor shaft. The setscrew should be turned clockwise to tighten and counterclockwise to loosen it. Make sure you only go one-half turn at a time on the setscrew when turning it clockwise. This action draws the face of the pulley together which constricts the width of the belt channel. This forces the belt channel out a little bit and if you overtighten the belt it can cause it to wear and tear and break down much more quickly.