This is a cutaway view of a typical cooler.

The evaporative cooler or “swamp cooler” as they are commonly referred to is truly a marvel of functionality and simplicity of design. Certainly we’re all familiar with how cool the air feels when we step out of the shower until we’ve dried off. This same principle is the basis for the evaporative cooler. Warm dry air is drawn from outside the home, passed across cooling pads that are kept continuously wet. The air passing through these pads evaporates the water which carries away the heat and cools the air. This air is then blown into the home at a 25 to 30 degrees temperature drop. Although very simple in their design it is still very important that certain details be taken into account to keep them running at their best efficiency.

Unlike air conditioning which draws air from inside the home cools or conditions it and returns it to the home as a closed loop. The evaporative cooler uses the dry outside air to accomplish the cooling process. This cooled air is then directed into the interior of the home. It is the air movement thru the unit from outside to inside the home that causes the cooler to produce the cool air.

It is this flow of air that causes the evaporative cooler to work at its most efficient. Without the steady easy flow of outside air there is no cool air produced. For this reason it is always important to have a window open in the home somewhere or perhaps several windows opened slightly to balance the flow throughout the home to insure this free flow of air. If all windows are closed or the house is sealed up tight, the efficiency of the cooler drops to almost zero.

When starting the cooler each day it is best to turn the wall switch to the pump only setting for about 5 minuets before turning it to the high or low cool settings. This starts the water pump and allows the cooling pads to become fully wet before the air begins to be pulled thru them.If this step is not taken and the blower is immediately turned on it’s possible that the pads do not get fully wetted. The water never makes it to the bottom of the pads and the lower portion of the pads remain dry. Hot air pulled in thru the pads is cooled where the water has started to soak the pads, however the dry part of the pads pass along the hot outside air and the efficiency of the cooler is greatly reduced. Be patient and give those pads the few minuets it takes to give the best service they can.

When kept well maintained a properly running evaporative cooler can drop the temperature as much as 30° from the exterior temperature and also helped to keep the interior the home at a higher humidity level so that the cool air has more effect.

At the end of the summer or early fall as the nights begin to cool thoughts change to preparing the swamp cooler for its winter storage. We will start this winterization checklist assuming that everything has been properly running and the cooler is in need of no major repairs. If it does they should be completed now or in the spring before startup.

I prefer to do maintenance in the springtime because most of the hardware stores and big box lumberyards carry extra supplies of evaporative cooler parts on a seasonal basis and they can be very difficult to find in the fall. If a cooler needs motors, pumps, pads, spider tubes or supply lines these things are much easier to get in the spring because of the seasonal supplies of the stores.

Let’s begin with winterizing a good running cooler that just needs to be put away for the winter.

Here is a  pro tip, but not required. Occasionally while winterizing a cooler I open it up and notice a lot of salts and deposits built up on the pads and on the sides of the cooler. I will drain off a little bit of water from the holding tank at the bottom of the cooler and pour in a gallon of white vinegar. Turn the cooler to pump only and allowed it to circulate the white vinegar for 30 to 45 minutes. This will help to remove many of the deposits and help to clean the interior of the cooler. The vinegar has a low acidic percentage rate so it will do no damage and will help to remove many of these deposits and the damage that they cause.

  1. The first step would be to turn off the water supply at the supply valve. It is usually located outside the house. Locations differ from home to home. After turning off the valve disconnect the line connection so the water can drain.
  2. Turn off the power at the breaker so that there is no accidental startup while you’re doing the maintenance. If that is not possible, turn the wall switch off and put a piece of tape on it stating that it is to remain off.
  3. Most coolers will have a drain which can be removed to drain the cooler of the standing water in the bottom. This can also be removed with sponges or with a shop vac whichever method works best for you. Be sure not to do any damage or scratch the inside of any coatings that may be on the inside of the cooler. The idea is to remove all of the water so that nothing is left to freeze when cold weather comes.
  4. On many coolers the blower motor and the pump motor plug into a power box at the top of the cooler, if it’s possible to unplug the blower motor and the pump this is a good idea to prevent accidentally being started and burned out if the wall switch is turned on unintentionally during the winter season.
  5. A step I like to take when I winterize a cooler is to remove the belt on the blower. Stretched over the pulleys unused for 7 months can cause belts to fail in just 2 seasons. This can be prevented by simply removing them and reinstalling them in the spring.
  6. Put several drops of oil in the bearing cups for the blower on both sides and rotated a couple of times to distribute. This will ensure that the shaft and bearing do not seize after a long period of no movement.
  7. Some will recommend that this is a time to change the pads on the cooler, however, as I’ve said, this is something I like to do in the spring if it needs to be done. They’re much easier to find them at the local stores because of seasonal supplies. Others choose to do it now so that it’s ready to start right up in the spring. Either will work.
  8. It is now time to cover the unit. Again, an extra step I like to take when I winterize a cooler is to wrap it with shrink wrap plastic. This allows the cooler to be wrapped tightly and stops air and dust that inevitably gets past the canvas cover. Install the cover. Covers are available at most hardware stores. It is simply a matter of measuring the cooler you have and buying the proper size of good quality canvas. A good one will last 10 years if applied properly and kept tight. The majority of the damage to covers is usually caused by hard wind and a lose cover that is allowed to flap.
  9. The final step in is on the interior of the home where the vent for the cooler enters the house. It is important to plug or cover this area. Many times I’ll remove the vent and The cooler pillow is inserted into the vent area behind the vent cover to stop winter drafts.install a cooler pillow if one is available, if not, a sheet of cardboard cut to fit tightly over the vent on the back and reinstalled is adequate. Remember that even though there is a cover on the outside of the cooler it is sitting still out in the cold. That air is going to move inside the house if not blocked. It is important to cover this vent.
Spring startup

Preparing for use in the spring is pretty much the reverse of the steps for winterizing in the fall.

  1. remove the interior vent cover. remove the cover and the plastic if it was installed. If not done in the fall, inspect and replace the pads if they look worn, if you can see thin or missig material, or if there is a lot of water deposits on them and can’t be hosed off.
  2. Reinstall the belt if you removed it
  3. If they were unplugged plug the motor and the pump in
  4. If rust is developing in the pan at the base of the cooler where the water level normally stands before adding before proceeding to fill the cooler it would be good to use any of the available cooler coatings that help protect it and will add many years of use and also stop any damaging leaks that can develop
  5. If the drain plug was removed install it used to fund tape and install it.
  6. Attach the supply line to the cooler and turn on the water.
  7. Turn on the water allow the pan to fill and adjust the float is needed to bring the water level.
  8. Place several drops of oil in each of the two bearings on the blower housing.
  9. Install all but one of the panels
  10. Internal controls which the wall switch to pump only in ensure that the pump operates properly and that the water is equally distributed to all the panels thru the black tubes.

If everything looks good install the last panel and you’re ready turn the cooler on low cool go inside the home and ensure that no water is dripping there are no leaks and that the area been cooled correctly properly that it is functioning properly you now ready for those hot dry a Colorado days that we enjoy so much.