Most problems with conventional evaporative coolers (also called swamp coolers) result from neglected maintenance. Evaporative coolers need an inspection and major cleaning at least yearly to remain energy efficient. In very hot climates, where the cooler operates much of the time, you should inspect the pads, filters, reservoir, and pump at least once a month. Be sure to disconnect the electricity to the evaporative cooler before cleaning or servicing it.
Dust from the air, and minerals and dirt from the water, will collect in your evaporative cooler’s reservoir. Save yourself a lot of work and money by draining this reservoir regularly. All coolers have a drain fitting at the bottom of the unit. This fitting is usually connected to an overflow tube. To drain the reservoir, shut off the water, connect a garden hose to the fitting on the outside of the cooler cabinet, and then unscrew the overflow tube.
Replace the pads at least once during the cooling season. Some paper and synthetic cooler pads can be cleaned with soap and water or a weak acid solution. The filters, if the cooler has filters, should be cleaned when the pads are changed or cleaned.
Inspect the fan blades. If there is any significant amount of dirt on the blades, clean them with a brush and soap or cleaning solvent. Scrape the scale off the louvers in the cooler cabinet and clean the holes in the drip trough that distributes the water to the pads. The reservoir should be thoroughly cleaned each year to remove biological matter, scale, and dirt. Most manufacturers also recommend painting the reservoir area once a year with a water-resistant rust-proof coating.
The pump and the float assembly are the source of many maintenance problems in evaporative coolers. Clean these components thoroughly to keep your evaporative cooler in top condition.