Some Evaporative Cooling Basics

1. A thermostat(1) sends a message to your evaporative cooler that it’s too hot.
2. Both the pump(2) and the blower(3) are activated. On newer model thermostats you may have a delay feature that actives the pump(2) a few minutes prior to activating the blower(4).
3. The pump(2) saturates cooling pads(5) with water being pumped from the reservoir(6) through a flexible tube manifold(3).
4. Hot air is pulled through the cooling pads(5) by the blower(4). As this air passes through, the water evaporates thereby cooling the air.
5. Inside the same blower(2) pushes the cooled(7) air into your house.
6. The cooled(7) air will then push the warm(8) air out. This is accomplished by having open windows, doors, or specially designed attic vents.
7. This flow also continues until the process is stopped by a message from the thermostat(1) that it’s cool enough.

That’s really nice, right. But what does all of it mean to you?
It means there are routine maintenance requirements and opportunities.

Some Evaporative Cooling Problems:

1. The Thermostat

  • Some require batteries to operate. If the batteries are not changed at least once every year they can cause erratic behavior in your evaporative cooler.
  • Because thermostats operate on electrical power there is a possibility of wire and connection corroding or shorting out.

2. The Pump

  • Your cooler is exposed to the elements so dirt, dust, and pollens collect inside and turn into mud. This mud can accumulate in the impeller housing preventing it from rotating freely, causing it to work harder and use more electricity. This causes additional wear and tear on the pump motor and can shorten its life span.
  • Adding to the accumulation of mud are minerals from the water. As water evaporates minerals are left behind.
  • Because the pump is on the exterior of your home it is susceptible to freezing. This can result in the damage to the operational parts.

3. The Flexible Tube Manifold

  • The same mud that accumulates in the impeller housing and cooling pad debris can get pumped into the tube manifold causing a blockage.

4. The Blower

  • A belt referred to as a “V-belt” in conjunction with a motor turn the blower fan. This belt can become frayed, cracked or loosen reducing the blower’s ability move air through the cooler and into your home.
  • The blower fan bearings can also accumulate dirt and mineral deposits and require lubrication. This is usually identified by loud squeaking sounds coming from the blower.
  • The blower motor also has bearings that will wear over time. A V-belt that is too tight can reduce the life of the motor. Most motors are permanently lubricated; however there are still some that require lubrication.

5. The Cooling Pads

  • Cooling pads will become clogged with dust, pollen, and mineral deposits. This reduces the cooling efficiency, overworks the blower motor, and reduces airflow. Pads should be replaced annually.
  • When a cooling pad is not saturated no evaporation takes place and the air passing through that pad is not cooled. This reduces cooling efficiency.

6. The Water Reservoir

  • A float similar to the one in your toilet controls water level in the reservoir. Adjustments to the float weaken the arm eventually causing it to break. Adjustments are required when water is overflowing the reservoir or cooling pads are not being properly saturated. Ensure the cooler is sitting level.
  • Dirt, pollen, minerals, and cooling pad debris get deposited into the reservoir as well. The reservoir needs to be cleaned to prevent this mud and debris from impacting the operation of the cooler as a whole.
  • Metal reservoir pans will corrode over time and if the coating is compromised. “Bleed-off” kits are available to continually flush out minerals, neutralizers that are placed in the reservoir are available, or the reservoir can be drained and refilled twice per month.

7. The Cooled Air

  • Evaporative coolers work on the principal that cold air is heavier than warm air. Proper placement of supply air vents is crucial to effective operation.

8. The Hot Air

  • As with all cooling systems, for your evaporative cooler to work properly an escape route must be provided for the hot air. You must have the ability to allow the same amount of hot air to escape as the amount of cooled being blown in by the blower. When this is not the case you may notice a musty smell and little apparent temperature change.
  • Attic vents may not be operating properly or there may not be enough ventilation in the attic to allow enough air to escape.
  • You may need to open additional windows and doors.

9. The Water Source

  • Any portion of the water line from your water source to the reservoir that runs along the exterior or an uninsulated portion of your home is susceptible to freezing. If this happens it will most likely result in a leak. The water line must be disconnected and properly drained prior to the first freeze.
  • When plastic tubing is used in place of copper tubing a freeze may not cause a leak. Plastic will become brittle with exposure to the elements, eventually causing a leak.

Some Evaporative Cooling Solutions:

  • Prior to the first freeze your evaporative cooler should be completely drained, cleaned, and disconnect at the water line source (winter-ized). You may want to cover the cooler to prevent drafts and turn off the circuit breaker or disconnect from the power source to prevent damage from power surges. You or a hired professional, depending on your comfort level, can do this. When performing this on your own use extreme care on the roof and ensure the circuit breaker is turned off or the cooler is disconnected from the power supply.
  • After the last anticipated freeze your system should be cleaned and inspected, also referred to as tuned-up (summer-ized). Make sure this cleaning and inspection is very thorough. It should at least address each of the potential problems mentioned here. You or a hired professional, depending on your comfort level, can do this. When performing this on your own use extreme care on the roof and ensure the circuit breaker is turned off or the cooler is disconnect from the power supply.
  • During the spring when cooling needs are not great and cool air is available from outside, your cooler can be operated in fan only mode. Care must be taken that the pump is only operated with water in the reservoir.