How to Clean an Air Cooler Water Tank

To clean an air cooler water tank, unplug the cooler, drain the tank, scrub it with mild soap and water, rinse well, dry it and refill with fresh water.

Evaporative air coolers, also called desert coolers, are common in the UAE for garages, workshops, tents, labour accommodation and outdoor areas. Their water tank sits full of warm water for days, so it picks up scale, slime and dust. A dirty tank makes the cooler smell, blows that smell into the room, and can breed bacteria and mosquitoes. This guide shows how to clean it safely and how often to do it.

Why an Air Cooler Tank Gets Dirty

• Scale. Minerals in the water are left behind as it evaporates and form a white or grey crust.
• Slime and algae. Warm standing water and light on a clear or translucent tank encourage growth.
• Dust and sand. The cooler pulls in air, and dust settles in the tank and on the pads.
• Stagnant water. Water left standing for days goes stale and can attract mosquitoes.

What You Need

• Mild dish soap
• White vinegar, for scale
• Soft brush or sponge, and a toothbrush for corners
• Clean cloths
• Bucket and a hose or jug
• Gloves

Do not use harsh chemicals, strong acids or wire brushes. They can damage the plastic tank and the pump, and fumes are not good in a closed room.

Step-by-Step: How to Clean an Air Cooler Water Tank

Step 1: Unplug the cooler

Switch it off and unplug it from the power. Never clean a cooler while it is connected to power, because it has an electric pump and water.

Step 2: Drain the tank

Open the drain plug or tip the water out into a bucket. Use the drain valve if the cooler has one. Do not pour the water over the electrics.

Step 3: Take out the removable parts

Lift out the pump, the float and the distribution pipe if they come out easily. Take out the cooling pads and shake the dust off, or rinse the pads gently, following the cooler maker's instructions. Dirty or worn pads should be replaced.

Step 4: Scrub the tank

Mix mild soap in warm water and scrub the inside of the tank, the corners and the base with a soft brush. For white scale, wipe or soak the area with a half-and-half mix of white vinegar and water for 15 to 30 minutes, then scrub again.

Step 5: Clean the pump and the water path

Wipe the pump housing and the water inlet. Clear any scale from the small holes in the distribution pipe, using a soft brush or a toothpick. A blocked pipe leaves dry patches on the pads and the air gets warm.

Step 6: Rinse well

Rinse the tank several times with clean water until there is no soap or vinegar smell left. Rinse the pads too if you removed them.

Step 7: Dry and refit

Let the tank and pads dry in the shade, refit the pump and the pads, and check the pipes are connected.

Step 8: Refill with fresh water

Fill the tank to the marked level with clean water, and plug in the cooler. Check that the water circulates and wets the pads evenly.

How Often Should You Clean an Air Cooler Tank?

As a rule of thumb:

• Change the water often when the cooler is in daily use, and do not leave old water standing in it.
• Give the tank a quick wipe and rinse regularly during heavy use.
• Do a full clean, including scale removal, about once a month in the hot season, and always before you store the cooler.
• Empty and dry the tank completely if the cooler will not be used for a while.

Check the cooler maker's manual for the schedule and the cleaning products they allow.

Tips to Keep the Tank Cleaner for Longer

• Keep the cooler out of direct dust and sand where you can.
• Place the cooler in shade, because warm water in sun grows slime faster.
• Cover the tank opening when you fill it, and keep insects out.
• Use softer water if scale builds up fast.
• Replace the pads on time, because worn pads shed fibres into the tank.

A Note on Larger Water Storage Tanks

An air cooler tank is a small, open reservoir. A household or building water storage tank is a different thing. It holds drinking and domestic water in much larger volumes and needs a different cleaning method, including disinfection. For that, read our guide on how to clean a water tank step by step or the water tank cleaning and maintenance guide. To stop slime in a larger tank, see how to prevent algae in a water tank.

Frequently Asked Questions

Q: How do I clean the water tank of an air cooler? A: Unplug the cooler, drain the tank, remove the pump and pads, scrub the tank with mild soap and water, remove scale with a vinegar and water mix, rinse until there is no smell, dry it and refill with fresh water.

Q: What can I use to remove scale from an air cooler tank? A: White vinegar mixed half and half with water works for light scale. Wipe or soak the area for 15 to 30 minutes, then scrub and rinse well. Avoid strong acids and harsh chemicals.

Q: How often should I change the water in an air cooler? A: Change it often when the cooler is in daily use, and do not leave old water standing. Stale water smells and can attract mosquitoes.

Q: Why does my air cooler smell bad? A: Usually because the tank or the pads hold stale water, slime or scale. Drain the tank, clean it and the pads, and refill with fresh water. Replace the pads if they are worn.

Q: Can I use bleach in an air cooler tank? A: Check the cooler maker's manual first. Many makers advise against strong chemicals because they can damage the plastic and the pump, and fumes are unpleasant in a closed room. Mild soap and vinegar are the safer routine.

For household and commercial water storage tanks, WhatsApp KHAZAAN on +971509583173 or email khazaanae@gmail.com, or see our water storage tanks.