Evaporative Cooler Not Cooling? 8 Things to Check

An evaporative cooler cools by blowing air through wet pads. If the air coming out isn’t cool, the cause is almost always one of three things: the pads aren’t wet enough, the air can’t flow through the house, or the weather is too humid. Work through these checks in order.

1. Open some windows or doors

Unlike a refrigerated air conditioner, an evaporative cooler needs somewhere for the air to go. With the house shut up, the air stops moving and the house turns humid and warm. Open windows or doors on the opposite side of the house to the cooler, a few centimetres per room being cooled.

2. Check the weather

Evaporative cooling works best in dry heat. On humid or stormy days, the air can’t take up much more moisture, so it can’t cool as much. If the cooler works well on dry days but struggles on muggy ones, nothing is broken.

3. Make sure the cooler is in cooling mode

Many controllers have a fan-only or vent mode that runs the fan without wetting the pads. Check the mode on the wall controller before climbing on the roof.

4. Look at the pads

From a safe position, check whether the pads are evenly wet. Dry stripes or dry pads mean the water isn’t getting there. Check the next three items.

5. Is there water in the tray?

If the tray is empty, check the water tap to the cooler, then the inlet solenoid valve and the float valve or water sensor. A drain valve stuck open will also empty the tray as fast as it fills. See our solenoid valve guide.

6. Is the pump running?

If there’s water in the tray but the pads stay dry, the pump may have failed, or its hose or water distributor may be blocked. Pumps commonly fail from age or scale. See how to replace a cooler pump and which pump size you need.

7. Are the pads clogged or worn?

Pads clogged with scale, dust or algae restrict airflow and don’t wet evenly, so the cooler blows less air and it’s warmer. Pads also wear out over time. See when to replace cooler pads.

8. Is the fan moving enough air?

Weak airflow can be a slipping or worn fan belt on belt-drive units, or a failing motor or capacitor. See our fan belt guide and capacitor or motor?.

Still not cooling?

If the pads are wet, the fan is strong and the windows are open, the cooler may simply be undersized for the area, or a control fault may be at play. A cooler technician can check it. If you’ve found the faulty part, browse evaporative cooler parts or send us your cooler model and we’ll help you find the right part.

Popular replacement parts

• Seeley Tornado Pump Breezair / Braemar / Coolair (095806)
• Fasco JRM28 Pump for Bonaire / Celair / CoolBreeze Coolers (JRM28)
• Brivis Askoll M115 Pump #B017245 – AD, PRO and more (B017245)
• Seeley Breezair / Braemar 24VAC Solenoid Valve #638638 Long Lead (638638)
• Bonaire Solenoid Valve 24V 15mm With Dump/Bleed (6051636SP)
• Breezair Chillcel Pads Pack of 4 – EM, ES, EX, EXD, EXQ, EXH (114613)
• Bonaire Filter Pads Celdek Medium VSM 60-65 (6050115SP)

This guide is general information only. Always follow your cooler manufacturer’s instructions, and use a licensed electrician for any electrical work.