Swamp coolers are a budget-friendly way to cool shops, garages and patios through a long Texas summer. But once fall arrives, that same cooler can become a liability. Water left in the lines can freeze, cold air can leak in through the duct, and minerals can eat away at the pan over the winter. The good news is that winterizing an evaporative cooler is simple. Follow these six steps, and your cooler will be safe through the cold months and ready to go in spring.
Planning to keep your space warm with a portable heater once the cooler is off? Read our guide on what a convection heater is and how to use one safely first.
When Should You Winterize Your Swamp Cooler?
In Burleson, the best time is late October through mid-November, after the last warm spell and before the first hard freeze. Our winters are usually mild, which makes it easy to forget the cooler. Then an arctic front drops overnight lows into the teens, and an undrained water line can split overnight. Do not wait for the first freeze warning on the news.
Before You Start: Safety First
- Turn off the power at the cooler switch and the breaker or outdoor disconnect before touching anything.
- Use a sturdy ladder and have a helper if your cooler is on the roof. Never work on a wet or icy roof.
- Wear gloves. Cooler pans and panels can have sharp edges and mineral crust.
- Gather supplies: an adjustable wrench, a bucket, a stiff brush, white vinegar, rags, and a fitted cooler cover.
Step 1: Shut Off and Disconnect the Water Supply
Find the shutoff valve on the small water line that feeds the cooler. It is often under a sink, in the attic, on an outside wall or near the water heater. Close it completely. Then use a wrench to disconnect the supply line at the float valve inside the cooler. This stops new water from entering the unit and protects the line from freezing.
Step 2: Drain the Pan and the Water Line
Open the drain plug or overflow fitting at the bottom of the cooler and let the pan empty completely. Next, drain the supply line itself. If you can, blow air through the line or hold the open end lower than the rest of the tubing so the water runs out. A small amount of trapped water is all it takes to crack copper or plastic tubing when the temperature drops below freezing.
Step 3: Clean the Pan and the Interior
North Texas water is fairly hard, so most coolers end the season with a crust of white mineral scale, sediment and sometimes algae. Scoop out any debris, then scrub the pan with a stiff brush and a mix of equal parts white vinegar and water to loosen scale. Wipe everything dry. A clean, dry pan resists rust over the winter and helps prevent the musty smell many people notice at spring start-up. If you see rust holes or a pan that is flaking apart, make a note for spring repairs.
Step 4: Remove or Replace the Cooler Pads
Old pads hold minerals, dust and moisture, which are perfect conditions for mold. Remove the pads now instead of leaving them in all winter. Aspen pads are inexpensive and usually need replacing every season, so simply discard them. Rigid media pads can last several years. Rinse them gently, let them dry completely and store them indoors, or leave them dry in the cooler if the unit will be fully covered. Either way, installing fresh pads in spring gives you better cooling and cleaner air.
Step 5: Disconnect the Pump and Check the Motor
Unplug the water pump, empty any water from it and wipe it clean. Many homeowners store the pump indoors over winter to protect it. While you are there, inspect the blower belt for cracks or fraying, check that the pulleys are tight and look for signs of wear on the motor. Catching a worn belt now saves a surprise breakdown on the first hot day of the year.
Step 6: Cover the Cooler and Seal the Indoor Vent
Install a fitted, weather-resistant cover over the outdoor unit and secure it with straps so Texas winds cannot pull it loose. Then head inside and close the ceiling or wall vent where the cooler air enters your home. Add a magnetic vent cover or insulated cooler duct plug for an even better seal. An open cooler duct acts like a chimney, letting warm air escape and cold drafts pour in all winter. Sealing it can make a noticeable difference in comfort and heating bills.
For portable coolers, empty the tank, clean it, let it dry with the lid open and store the unit indoors.
What to Do in Spring
When warm weather returns, reverse the process: reconnect the water line, open the valve, install new pads, reconnect the pump and power, and run the cooler while checking for leaks and steady water flow across the pads. Pay attention to strange noises or weak airflow, which may mean the motor or belt needs service.
If your cooler struggles to keep up on humid summer days, it may be time to consider an air conditioner. Our article on how to find the tonnage of an AC unit explains how cooling capacity is sized.
When to Call a Professional
DIY winterizing works well for many homeowners, but call a technician if your cooler is on a steep or high roof, the water line is already cracked, the supply valve is stuck, or you notice electrical problems. HVAC Repair Burleson offers complete swamp cooler winterization and spring start-up, plus swamp cooler repair for pumps, pads, floats and motors. Call (817) 839-0304 to book before the first freeze.
