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Guide to Evaporative Cooling

Easy, Step-by-Step Instructions to Maintaining Your Cooler to Ensure a Safe, Comfortable, COOL Summer Season!

A. Introduction
B. General Rules of Safety
C. How to Size Your Evaporative Cooler
D. Spring Start-Up
E. Tools & Equipment
F. Okay! Here We Go!

A. Introduction

Well, it's that time of year again. Time to make the annual climb up on the roof and do battle with your evaporative cooler. For the past five years now, it's been the cooler five, you zero. Let's see if we can give you so tips so you can turn the score around this year.

The job can be made a lot easier and less time consuming with this easy cooling guide from Naughton's. We think you'll find this guide to be helpful and informative and one that you will want to keep around for handy reference in the event your cooler is not performing properly.

If a problem should arise that’s not covered here, please feel free to call the staff at any of our four Naughton's stores and they will be happy to assist you in getting your cooler running in tip-top shape.

B. General Rules of Safety

1.  Disconnect electrical power at the fuse or breaker box and remove the motor and pump plug from the junction box before you begin installation or servicing your cooler.

2.  Installation of your cooler must conform to local codes and utility standards. The staff of experts at Naughton's are ready to help you with any questions that you may have in this regard.

3.  Wear rubber-soled shoes when working on the roof of your house.

4.  Make sure the mounting surface on your roof will support the weight of your cooler.

5.  Don't install or service your cooler during rain or high wind weather conditions.

6.  Keep your children a safe distance from where you are working.

7.  If you work with power tools, wear protective eyewear and gloves.

8.  Have adequate means to raise the cooler to the roof to prevent damage to the cooler and injury to yourself. Removing the pad frames from the cooler prior to raising the cooler to the roof can make the job much easier.

9.  Never drain your cooler onto the roof. Use a hose connected to the drain fitting to drain the water off the roof. Water residue could stain your roof or cause you to slip.

10.  Always use the right tools. Never try to do a job without the right tool.

C. How to Size Your Evaporative Cooler

Getting the proper size evaporative cooler is critical. One that is too small will not cool your home property and one that is too large will result in excessive utility bills.

Residential evaporative coolers come in 6 different sizes ranging from 3000 to 6500 cubic feet per minute (CFM). The proper size of a cooler is determined by the amount of cubic feet in the area to be cooled. The term  “cubic feet per minute” refers to the cubic feet of air in your home and the amount of air needed to replace that in one minute. In the Southern Arizona area it has been determined that a complete air change every two minutes is most desirable.

The formula  for sizing your cooler is very simple; just multiply the length by the width by the height of the area to be cooled and divide by two.

Example: A home that is 25 feet wide x 40 feet long x 7 feet high has a total of 7000 cubic feet of area to be cooled. Using the factor two (for an air change every two minutes), divide 7000 by two to give you your CFM requirement, in this case 3500 CFM.

You should choose a cooler larger than 3500 CFM.  As always, any questions you may have regarding sizing please feel free to ask the staff at Naughton's.

D. Spring Start-Up

Before actually working on your cooler, it's a good idea to examine your cooler carefully. Make sure that all mechanical parts are in good working order such as motor, pump, float valve etc. Make a note of the specifications and sizes of the parts that need replacing. If the item to be replaced is not marked, bring it into Naughton's and they will determine the proper replacement for you. In any case, it's always a good idea to bring in the defective part to remove any area of doubt. Jot down the size of the cooler pads, belt, motor and pump and keep these in a handy place in your home. It could save you an unnecessary trip to the roof.

E. Tools & Equipment

The following tools and equipment are some of the items you may need for quick and easy preparation of your cooler for a trouble-free season:

  • Wire brush
  • Paint scraper
  • Rust-resistant spray paint
  • Submarine Sealer cooler coating
  • SAE #20 non-detergent Motor Oil
  • Pliers
  • Philips and Slotted screwdrivers
  • Tubing cutter
  • Level
  • Wire nuts
  • Adjustable wrench
  • 5/32 hex wrench
  • Drill
  • Hammer
  • Duct caulking
  • Electrical tape
  • New cooler pads
  • Ladder

F. Okay, Here We Go!

1.  Disconnect electrical power at the fuse box or circuit breaker panel. This will avoid a potentially hazardous condition when working with electricity around water.

2.  Pull out slide damper. Not all cooler installations include a damper. If you have a damper, you should find it located in the vertical duct leading from the cooler to the roof.

3.  Take out pad frames and take them to an area where it is convenient to work on them. Next, it is very important to clean the pad frames thoroughly, removing alkali and corrosion build-up on the louvers. A wire brush is excellent for this purpose. To make this job easier, Naughton's has a cooler cleaning chemical which dissolves alkali on contact. Rubber gloves should be worn when using the chemical cleaner. Follow the directions carefully.

4.  Paint the pad frames. After making sure that the alkali and rust build-up has been removed, paint the frames with a rust resistant paint. Don't scrimp here! Use a light colored paint with reflective quality.

 5.  Clean the pan (bottom portion that stores water). Remove all alkali, rust deposits, dirt and loose aspen.

6.  Coat the pan. Use undercoater for a long lasting job!  Our Submarine Sealer cooler coating is especially designed for coolers and will not become brittle or crack. It's available in gallons, quarts, and the easy-to-use spray can.

 7.  Take off the belt. Examine carefully for splits and worn areas.  If the belt needs replacement, the belt size is usually printed on the belt beginning with the designation “4L”.  If there is no indication of size, bring the belt into Naughton's to get the proper replacement.

8.  Check the blower wheel. Make sure it rotates smoothly. If not, this indicates the blower bearings need replacement.  Inspect the blower wheel to insure that it is tight on the shaft and that it does not wobble. Wobbling can result in noisy operation. Any wobble over 1/16" can cause problems.

9.  Examine motor pulley. Make sure it rotates smoothly. If the shaft will not budge or it is difficult to turn, replacement is indicated.  Make sure that the set screw on the pulley is tight on the shaft and also check that the set screw holding the movable shaft is tight. If either is loose, it will result in inefficient operation. Replace a bent pulley because this condition will result in noisy operation.

10. Make sure that blower pulley and motor pulley are aligned. If the pulleys are out of alignment, correct by moving the motor pulley on the shaft. This is an important step because pulleys out of alignment can cause wear to the belt and pulley and premature failure.

11.  Lubricate the blower bearings. If the bearings are oilable, fill the cups with SAE #20 non-detergent oil. Naughton's has an excellent grade of oil in a container with a "Zoom" spout.

12.  Lubricate the motor. Do not over-oil! Cooler motors require only three or four drops of SAE #20 non-detergent at the start of the season. This should be repeated every 90 days during use. Do not attempt to oil a motor that has no oil caps.

13.  Examine the blower shaft for excessive play. Try pushing and pulling on the blower wheel. The shaft should not move more that 1/16". This can be corrected by loosening the shaft collar on the end of the shaft opposite the pulley. Then adjust the play to within 1/15" and retighten. If there is too much play in the shaft this could result in noisy operation.

14.  Examine set screws on blower wheel. Make sure they are tight and that the blower wheel is in the center of the blower housing.

15.  Check the pump. Spin the shaft to make sure that it rotates freely. If the shaft is corroded or bent it will turn slowly or not at all. In this case, replace the pump. Naughton's suggests a pump that is grounded and has a thermal over-load protector, such as the Little Giant. Many professionals use the submersible model for longer life.  On the bottom of the pump you will find an inlet cap, remove the cap and clean out any obstructions.

16.  Check the overflow pipe. Make sure the gasket is sealing and the pipe is clean inside.

17.  Fill the pan with water. If you have used Submarine Sealer from Naughton's, you may fill it immediately. Some brands of undercoating require waiting for 12 hours to cure.

18.  Examine the water supply line (usually copper tubing).Look for any leaks in both the tubing and fittings which may have been caused by winter freezing.

19.  Inspect and test float valve. Lift the float to make sure that the float valve will shut off properly. If not, replace the float valve.  Naughton's recommends their heavy duty brass float valve for longer life.

20.  Set the water level. The water level should come up to 1/2" of the top of the overflow pipe. The water level can be adjusted by loosening a screw on the arm of the float valve, setting the arm to the desired angle and tightening the screw. This should be done while the cooler is running and the pads are wet. This allows room for the water in the pads to drain back into the pan when the unit is not operating.

21.  Turn on pump only. If pump is not operating or is pumping poorly, replace the pump. If pump is performing well, but water is not flowing in equal amounts from each distributor line, shut off the pump and clean out the distributor head and tube (the spider).

22.  Apply power to the motor that operates the blower. If the motor does not operate check for loose connections. Check both high and low speeds to see that they are operating.  If electricity is reaching the motor and it still does not operate, the motor may need to be replaced.  If just one of the speeds is operating, this indicates burnt motor windings on either the high or low speed, and the motor should be replaced.  Naughton's recommends a quality motor form A.O. Smith,  which is specifically designed for coolers.

23.  Inspect belt tension. This can be done very easily by pressing lightly on the belt midway between the motor and blower pulley.  There should be a deflection of anywhere between 3/4" to 1". If adjustment is required, loosen the bolts holding the motor backward or forward until the desired tension is attained. Re-tighten the bolts.

24.  Place new pads in frames. First make sure that the paint is dry.  When placing the new pads in the frame it is very important to have the right size. The pad must fit the entire frame to prevent warm air from entering the cooler without passing through the pad. The pad should be of high quality and uniform thickness. Pads that are thick in one area and thin in another will develop “hot spots” and will not cool properly. Pads that are too thin will not provide enough moisture to warm air entering the cooler. Pads that are too thick can severely restrict the flow of air and overheat the motor.

25.  Install pad frames and turn power on.

26.  Clean cooler cover. After cleaning the cover, spray with a protective canvas coating and store in a cool, dry place to prevent rotting due to mildew. The damper plate should be stored in the same location.

NOTE: Before turning blower on, turn on the pump and let it operate for about 10 minutes. This removes any dust accumulation from the pads and ensures that only cool air will enter the home when the blower is turned on.

All Done! Congratulations! Now, you can enjoy peace of mind from doing the job right. Naughton's wishes you a great cool summer!

Automatic Power Cleaning System

by Phoenix Manufacturing Inc.
(for all evaporative coolers)

  • Eliminates the need and expense of potentially harmful cooler additives.
  • Will save between $ 5.00 - $ 15.00 per month on your water bill depending on the area you live in and size of the cooler.
  • Reduces maintenance greatly.
  • Consistently clean water reduces algae, minerals, impurities, and odors.
Power Clean

Aspen Snow-Cool Pads

Cool & Clean as a Colorado Mountain Breeze!

  • Up to 25% more efficient than other cooler pads.
  • Made from clean & natural Colorado Aspen.
  • Convenient sizes to fit all popular coolers
Aspen Pad
1140 W. Prince Rd.
Tucson AZ 85705
(520) 293-2220
(800) 736-3278
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