Evaporative Cooler Maintenance Tips - Changing Cooler Belts

Evaporative Coolers – Maintenance Tips

Change Your Coolers Belts

            You might at first think that changing your evaporative cooler belt is easy. Why spend your valuable time reading about it? Keep reading; because this information could not only give more time between belt changes it could also possibly save bearing problems down the road, and hundreds of dollars in costly repairs.

Tips to Keep in Mind

            Most residential coolers originally come with a 4L V-belt (ex. 4L 55). These belts work just fine but, they usually stretch some through the life of the belt. When the belt stretches to the point where squealing is heard you often notice that it still looks to be in pretty good shape. Most people use the motor mount adjustments to tighten the belt and everything is fine. Or is it? Usually by the time the belt stretches again it must be changed. When it comes time to replace the belt, many owners neglect to readjust the motor mounts back to their original positions. This is where the trouble starts! When a brand new belt is put on the tension will be set far higher than the manufacturer’s suggested tension setting. Most people think the belt will just stretch again right? Big Mistake! This puts far more wear on the bearings and cause premature bearing and motor failure. Changing a bearing on a cooler that has had moisture in it for several years can be a nightmare!

Expert Suggestions

            To make your life easier, here are two suggestions. First, instead of changing the original belt with another 4L V-belt, try using an A V-belt (ex. A 55). The A belt width is the same and they are for heavy-duty wear. In sizing the A belt you must keep in mind that the A belt is always two sizes smaller than the 4L belt. For example, a 4L 50 belt means that this belt is 50 inches around if you measured the outside length. For an A belt that is 50 inches outside diameter the belt would be an A 48, because these belts are measured on the inside. So you always need the A belt to be two numbers smaller than the 4L belt to have the same size belt. These belts are a little more expensive but, they usually last twice as long with less readjusting.

            Second, make sure, with either belt you use, that you set the pulley tension to the original setting. To test tension, press on the belt half way between the motor sheave and the fan pulley. A 3lb. force should deflect the belt ¾ of an inch. Usually only two things will cause premature belt wear. Either the belt tension is too tight or the pulleys are not in line with each other. If both of these are correct you will get more life out of your evaporative cooler belts.