A swamp cooler, also referred to as an evaporative cooler, is an alternative to a traditional air conditioner. Swamp coolers are unique in that they do not use refrigerant and therefore are more energy efficient, which makes them better for the environment. They use a fan to recirculate air over a cool, wet pad known as a wick, and the cool, moist air is blown into the house.
Swamp coolers need annual maintenance to work efficiently. On some older cooler units, this includes lubricating the bearings of the motor-driven fan. Note that most swamp cooler units have sealed bearings that do not require added lubrication. If you have an old unit that has a lubrication port on the top of each bearing (usually there is one bearing on each side of the fan), this is an indication that you need to lubricate the bearings.
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How to Oil the Bearings of a Swamp Cooler
Step 1: Turn Off the Power
Before lubricating the bearings, turn off the circuit breaker supplying the swamp cooler at your home's breaker box.
Step 2: Turn Off the Water Supply
Turn off the water at the shutoff valve for the evaporative cooler. Drain the hose that brings water in. This can be achieved by blowing air into it to push the existing water out.
Step 3: Remove the Side Panels
Gain access to the cooler lubrication fittings by removing the side panels of the cooler unit.
Step 4: Unplug the Motor Cord
Look for a power cord near the top of the cooler housing, just inside one of the side panels. If there is a power cord plugged into the receptacle (outlet) on the housing, unplug the cord and set it aside. This is just a secondary safety precaution to ensure the power to the motor is off.
Step 5: Locate the Caps
Locate the lubrication cap at top of the bearing mount on each side of the fan. Clean each cap with a rag to prevent debris from getting into the lubrication port.
Step 6: Add Lubricant
You will need to use a special oil to lubricate the bearings. You can use 20-weight nondetergent SAE oil or a high-grade turbine oil, such as the lubricant sold in a Zoom Spout Oiler. This oiler is particularly handy because it has a long tube that pulls out of the spout; you fit the end of the tube into the oil port and squeeze the bottle to add the oil.
Step 7: Fill It Up
Gently fill each of the oil ports until it is full. Try to squeeze so that just a drop or two comes out at a time. Wipe up any spilled oil with the rag and snap the oil cap into place.
Step 8: Reinstall the Panels
Plug the motor cord into the receptacle, if applicable. Fit the side panels back into place on the cooler housing.
Step 9: Turn On the Water and Power
Turn on the water supply to the cooler at the shutoff valve. Turn on the circuit breaker to restore power to the cooler.
Seasonal Maintenance Tips
It is recommended that you shut off the evaporative cooler for the seasons you are not using it to prevent mold. This is especially true for winter, since it could freeze and potentially damage the cooler. When doing this, you can also drain and clean the water pan. The pan needs to be drained and cleaned periodically to keep it functioning and prevent mold, mildew, and mineral buildup. You want to cover the swamp cooler in the fall and winter. Tie it down and seal the vent coming into your home with a damper to keep out dust and cold air. Change the evaporative pads before using it again in the spring or summer.
- HVAC How To: How to Oil the Bearings on a Swamp Cooler
- Wirecutter: Swamp Coolers Are a Cheap AC Alternative for Dry Climates. Here’s What to Know Before You Buy.
- Mechanic Base: What Does SAE Stand for in Motor Oil? (Letter Explanation)
- Energy.gov: Evaporative Coolers
- HowStuffWorks: How Swamp Coolers Work
- Pima County Public Library: Evaporative Coolers