Controller and power checks
If the wall controller's display is blank, the controller usually isn't getting power from the cooler, which points back to the switchboard or the isolator on the roof. Check the switchboard for a tripped breaker or safety switch, and reset it once. If it trips again, leave it off. A power outage can also leave a controller frozen or showing an error, and the manual usually explains how to reset it.
If the display works but nothing happens, check the mode. Many controllers have fan-only and cooling modes and a winter or off-season setting that stops the cooler running. Some also have a clock and timers that may be holding it off.
Water supply and winter shutdown
In cooling mode, many coolers fill the tank and run the pump to soak the pads before the fan starts, which can take several minutes. If the water was turned off for winter or the tank was drained, the cooler may wait, show a water fault or run without cooling. If the cooler's water supply has its own tap, check it's on. The manual or your installer can tell you where it is.
Coolers shut down for winter sometimes have the roof isolator turned off as well, and that switch sits on the roof next to the unit. Don't climb up to reach it. It's a job for someone with proper roof access.
When it needs a technician
If the power, controller and water are all fine and it still won't start, the cause is usually in the roof unit: a pump seized after months of sitting, a failed motor, a broken belt, a damaged control cable or moisture in the isolator. These need testing on the roof, with any electrical faults handled by a licensed electrician.
What you can safely do now
- Check the controller's display, mode and any timer or winter setting.
- Check the switchboard for a tripped breaker or safety switch, and reset it once.
- Make sure the cooler's water supply is turned on.
- Wait a few minutes after starting to allow for the fill and pre-wet cycle.
- Don't climb onto the roof to check the cooler or its isolator.
Services that can help
Read more in our guides
Related questions
- Why is my evaporative cooler noisy?Most cooler noise comes from wear and loose parts: fan bearings that grind or squeal, a worn or slipping belt, panels and pad frames rattling in the wind, a pump humming…
- How do I tell which switch has tripped on my switchboard?Open the switchboard door and look along the rows of switches.
- How do I clean my split system filters?Turn the unit off, lift the front panel, slide the filters out and vacuum off the dust.
- My air conditioner won't respond to the remote. What can I check?Start with the remote: fresh batteries, a clear line to the indoor unit, and no lock symbol or odd mode on its display.
Sources for this answer
1 source, with the date each was checked
- 1.Energy Safe Victoria: Locate your electricity box outside your home and check whether the safety switch has tripped. If it has tripped, reset the switch. If the switch won’t reset, call a licensed electrician. Accessed 30 September 2026.
General information for homes in Victoria. Every installation is different, so treat this as a starting point. Where this answer refers to Victorian safety or rental rules, the sources above have the current requirements.