Evaporative Swamp Cooler Repair

An evaporative cooler is a water-based system that cools the air by increasing the humidity. Here are some repair tips.

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Rachel Polant

Oct 25

Swamp Cooler Repair Basics: What You Need to Know if You Have an Evaporative Cooler

An evaporative cooler needs maintenance and repair just like any other HVAC system. In many areas, a swamp cooler can be in use nine months of the year. The reprieve is short, so you don’t have much time for repairs before the hot weather begins.

Those that have an evaporative cooler installed probably know that it is a water-based system that cools the air by increasing the humidity. Even though an evaporative cooler is a simple concept that has been around since the Egyptian times, it actually has many complex parts, including the water reservoir, air pumps, electrical connections, and fan. There are quite a few parts that can break.

Locating the Problem

Is there any air coming out of the unit?

If the unit won’t start or produce cool air, first check to see if you blew a fuse or tripped the circuit breaker. It may be as simple a fix as replacing a fuse or resetting the tripped breaker. But, if it happens again, the wiring to the unit should be checked for signs of damage.

If the problem was never the breaker or a fuse, you should check the thermostat, or timer, if one is installed. Use a voltmeter to see if power is going to the thermostat and that the switch is opening and closing properly. It may just have to replace the batteries in a programmable thermostat. But if it’s not working, you’ll need to replace it.

However, if the thermostat or timer is working properly, check the motor to see if everything is in proper working order. Look over the belt, and make sure it is on and adjusted correctly. If the blower motor is hot, let it cool down by shutting the power off to the unit. After the motor has cooled off, turn the power back on and check motor operation. If the motor still doesn’t work, it’s time have a pro who specializes in evaporative cooling repair take a look at it. The motor probably needs to be replaced.

Airflow Is Poor?

If the evaporative cooler runs but is not supplying enough air, you should make sure there is enough exhaust supplied. Check the exhaust ducts to see if they are blocked in any way. If exhaust ducts are not installed in your house, then windows or doors need to be open for proper airflow. Check your owner’s manual for instructions on what a sufficient opening is. If the proper amount of exhaust is available and air flow is still poor, then check the blower motor’s operation and the belt tension.

Airflow is good, but the system is not cooling?

Check the water system if you have good airflow but inadequate cooling. Look at the water pump to make sure it is operating and that the distributor is not clogged. Check to make sure there are no dry or open spots on the pads.

Evaporative Cooler Troubleshooting Other problems

If excessive water usage is the problem, it could be the float valve. The valve should be adjusted to maintain the sump level without any overflow. You normally adjust the valve by bending the rod, but if the valve is adjusted properly and water is still leaking, the seat on the valve is bad and the float valve should be replaced.

If your home is overly humid, ensure that you have proper exhaust air flow. If humidity is an issue, you may want to install exhaust ducts in the individual rooms.

A musty odor could be caused by stagnant water in the cooler or mildewy pads. Check and replace the pads as necessary. If you have stagnant water in the sump, you should drain and clean the reservoir. You may also want to install a bleed-off kit. This removes some of the water and replaces it with fresh water automatically.