Swamp Cooler Keeps Shutting Off? 7 Possible Reasons Why

Swamp Cooler Keeps Shutting Off

How’s your swamp cooler doing?  Keep shutting off?

Before even answering those questions, let’s address the name.  Swamp cooler.  Not exactly the loveliest of titles.

Of course, like a lot of appliances, swamp cooler isn’t the official name.  Just like fridge isn’t the official title of a refrigerator and idiot box isn’t the official title of a television.

Although you do get bonus points if you understand the idiot box reference and the fact televisions were actually shaped like boxes in the recent past.

Okay, enough with the history lesson.

The point is a swamp cooler’s actual title or name is an evaporative cooler.  It cools through a process of evaporation (more on that below).  Based on the swamp nickname, and the fact evaporation’s involved, you probably already figured out water’s involved, too.

But hey, you already know all this. You’re no rookie.  You want to know why your swamp cooler keeps shutting off.

Well, let’s waste no more time and get to why your swamp cooler is shutting off and the possible reasons why.

1.    A Quick Refresher on Swamp Coolers

The big thing to remember about swamp coolers is they’re most effective in warm areas of relatively low humidity.  The reason for this is the swamp cooler essentially uses hot dry air and water to provide cooling air. 

For it to work properly, you need cool water supplied to the unit where a fan draws in dry air.  The air is drawn in across a moistened pad (thanks to that water supply).  The heat from the air is absorbed by the pad.  At the same time, the moisture in the pad evaporates into the moving air as a result of the heat.

This process both increases humidity and cools the air being discharged.

As you can see, the result is cooler air and higher humidity.  That’s why swamp coolers are popular choices where the air is dry, arid, and doesn’t experience tropical or higher humidity on a regular basis (like the U.S. southwest).

Oh, and it’s not called a swamp cooler because it makes your home feel like a swamp.  Rather, evaporative coolers, if they’re not cleaned regularly, can develop algae in the unit, hence the nickname.

2.  Is Your Swamp Cooler Getting Reliable and Consistent Power?

The first thing you might want to check if your swamp cooler keeps shutting off is if it’s getting water.

And that’s a perfectly fine thing to want to check first.

However, you might want to check the power source first, especially if you’re having issues with a unit that’s continuously cutting off.

Now you may think because it’s starting before shutting off that electricity isn’t the problem, at least not a power supply problem.  And you may be correct.

That doesn’t mean you shouldn’t eliminate the power supply right off the bat.

For a portable swamp cooler, all you need to do is check the outlet you’re using.  Make sure the outlet is good and that your swamp cooler doesn’t have competition with other items using the same outlet.

It’s always best, when using plug-in appliances, to use a dedicated outlet for it and it alone.  Too many things plugged into the same outlet can cause power fluctuations across all items using that same outlet.

In other words, the swamp cooler may be getting enough power to start up but not enough to keep running if there’s too much demand on the outlet.

For a whole house swamp cooler, you may need to check the voltage your unit is receiving compared to the rated capacity of the motors.  If the voltage is too high, the motor or motors will overheat and shut down to protect itself from potential damage.

Swamp Cooler In Perfect Conditions
Make sure your swamp cooler uses a dedicated outlet that is in good condition.

3.  How are Your Electrical Connections?

Just as a power supply that may be supplying too little or too much power can prevent a swamp cooler from running as it should, so can faulty or damaged electrical connections.

Once you’ve checked your power supply, you should also check your unit’s electrical connections, if you feel comfortable doing so.  If you don’t, you always have the option to contact a service technician.

But if you’re ready to inspect and possibly re-connect or replace defective wiring, be sure to secure power to the swamp cooler first.  Also, it would help if you had a wiring diagram with you.  Normally, you can visually tell if a wire is connected to a fan motor versus a water pump, but all the same, have a diagram to be sure.

Wiring diagrams are often found in manufacturer’s manual’s, like this one.  If not, you can also try an internet or Google search using a format like this, “[Brand and Model Number] evaporative cooler wiring diagram.”

If you find loose connections or wires that have come free, whether they’re to a motor or a thermostat or pump, tighten them down or reconnect them.  If they’re damaged wires, replace them.

Again, if you don’t feel comfortable doing any electrical repair, contact a technician.

If there are wires that are loose or damaged, hopefully those are the causes of your swamp cooler repeatedly shutting off.

4.  Is Your Swamp Cooler Getting Water?

Yes, the original question you probably had; is the swamp cooler getting water.  Well, if you’re asking this question and if you have a portable swamp cooler, you hopefully already checked the reservoir to make sure it has water.

If you’re out of water, you should also be getting an audible alarm before the swamp cooler automatically shuts off.  This function prevents the pump motor from overheating or going air bound due to the lack of water.

Now if you do have a full reservoir and the cooler is still shutting off, you may need to investigate your pump further or the float switch (if one is installed).  A stuck float switch could be telling the unit to turn off if it thinks the tank is out of water even though it isn’t.

The other issue would be a worn motor or bearings.  It could be a matter lubricating bearings or repairing/replacing the motor.  In either case, you should consult your manufacturer’s manual or service center for recommendations.

5.  Timing Issues

How often is your portable swamp cooler shutting off?  Is it every few minutes or every few hours?  Some coolers have a built in automatic shut-off that activates based on the number of continuous run hours.  If yours is designed to shut-off after five or ten hours of continuous cooling operation, for example, it may be doing exactly what it’s supposed to be doing.

Another thing to check out is your swamp cooler’s timer, if it has one.  You may think your timer is okay but if there’s a fault with it, it may be triggering the cooler to shut-off when it’s not supposed to. 

Swamp Cooler Connected And Working
Your cooler’s timer may be failing and causing your appliance to shut-off when it is not supposed to.

6.  Thermostat Issues

If you have a whole-house swamp cooler shutting off all the time it may be simply due to a bad thermostat.  If you have it at one setting but it’s operating as if it were set at another, more than likely you need to have the thermostat checked out and possibly replaced.

Speaking of thermostats, it’s also worth noting the location of the thermostat.  If it’s in an area where it’s exposed to cooler air, it may be shutting off the cooler based on a false “read”.  In this case, it’s just a matter of moving the thermostat to a better location.

7.  Belt Tension

If you’ve got a belt in your swamp cooler that’s not at the right tension, you could be dealing with a belt issue that can cause several issues, all leading to a cooler shutting off repeatedly.

The biggest issue when it comes to belts and swamp coolers is the belt being too tight.  A belt that’s too tight puts stress on the motor and motor bearings.  This can lead to issues with the bearings and a motor that’s overheating.

As mentioned above, a motor overheating will usually cause the cooler to shut down as a protective measure.  In that case, too much voltage was the consideration.  In this case, a belt that’s too tight may be the reason.

If a belt is too loose, it’ll usually slipping.  This will lead to poor evaporation and circulation because of the reduced air flow.  Eventually, the belt will probably come off completely or break.


If you live in a hot and dry climate and rely on a swamp cooler as your primary appliance for cooling your home or parts of your home, then one that continues to shut off on a regular basis can quickly move from annoying to pain-inducing.

Thankfully, there are usually about six possible reasons why the cooler keeps shutting off and a handful of ways to correct them.  Most may be within your capability to handle, but always remember help is usually just a phone call or e-mail away.

I've been helping homeowners with appliance repair since 2016. Starting out as an enthusiastic amateur, I've since worked with many Appliance, HVAC, and DIY experts over the last 7+ years. My mission is to help fix your appliances and prevent future issues - saving you stress, time, and money. Visit my author page to learn more! Read more