Cooler due for a check before summer? Book an evaporative cooler service in Perth, or if something has already failed, our evaporative air conditioner repairs team can fix it. Call (08) 9207 2370.
If your evaporative cooler is blowing warm air, the short answer is almost always the same: water is not reaching the cooling pads, or the pads themselves are dry, clogged or worn out. Evaporative cooling works by drawing warm outside air through wet pads, where the water evaporates and drops the temperature before a fan pushes it through your home. Take the water out of that equation and you are left with a noisy fan moving warm air around. Below we cover the common reasons an evaporative cooler is not cooling, the safe checks you can do yourself, and the point where it is time to bring in a licensed technician. An annual evaporative cooler service prevents most of these problems before summer.
Why your evaporative cooler is blowing warm air
The cooling only happens while the pads are wet. When you feel warm air at the vents, the fault sits somewhere in the water side of the system or in how the unit is set. Here are the usual culprits behind an evaporative cooler blowing warm air.
No water supply or a stuck valve or float
Every evaporative cooler needs a steady trickle of water to keep the pads saturated. If the isolation tap feeding the unit has been turned off (a common thing over winter), no water reaches the pads and the air stays warm. Inside the unit, a float valve controls the water level much like the one in a toilet cistern. If that float sticks shut or the valve fails, the tray runs dry and cooling stops.
Dry, clogged or worn cooling pads
Cooling pads do the actual work, and they do not last forever. Perth’s hard water leaves mineral scale that slowly clogs the pads so water can no longer spread across them. Old pads go brittle, channel the water down one side, or break down entirely, leaving large dry patches. Air passing through those dry sections is not cooled at all. Pads are a wear item and generally need replacing every couple of seasons, more often in dusty or hard-water areas.
Pump failure
A small water pump lifts water from the tray up to the top of the pads so it can trickle down through them. If the pump has failed, seized or lost power, the pads dry out within minutes even though the fan keeps running. A dead pump is one of the most common reasons an otherwise healthy unit suddenly starts blowing warm air.
Running in fan-only or vent mode
Most evaporative controllers have a separate “fan”, “vent” or “circulate” setting that runs the fan without turning on the water pump. It is easy to leave the unit in this mode by accident. The system will happily move air, but because the pump is off, none of that air is being cooled. Always check the mode before assuming the worst.
Very humid weather
Evaporative cooling relies on dry air, because the cooling comes from water evaporating into that air. On Perth’s rare humid, sticky days the air cannot absorb much more moisture, so the temperature drop is smaller and the output feels warmer than usual. This is normal physics rather than a fault, and performance returns as soon as the humidity falls.
Safe checks you can do before calling a technician
Before booking a repair, there are a few quick, safe checks worth running. Keep these to things you can reach and see without opening electrical parts or climbing on the roof.
- Check the mode: make sure the controller is set to “cool” and not “fan”, “vent” or “circulate”.
- Check the water is on: confirm the isolation tap supplying the cooler is turned on, especially at the start of the season.
- Listen for the pump: shortly after switching to cool, you should usually hear a soft hum as the pump primes and water begins to flow.
- Check that the pads are wet: if you can safely see the pads from ground level, they should look damp and evenly wet, not dry, crusty or discoloured.
If the mode is right, the water is on, and the pads still are not getting wet, the fault is likely mechanical or electrical, and that is where a professional should take over.
When it is time to call a technician
Pumps, fan motors, water valves, roof-mounted units and any electrical component are jobs for a qualified technician, not a DIY fix. A licensed professional can safely test the pump, replace worn pads, free or replace a faulty float valve, check the motor and wiring, and work at height on rooftop units. For the full picture of how these systems fail and get serviced, see our full evaporative air conditioner repairs guide.
Provista services and repairs evaporative cooling across Perth and surrounds. If your system is blowing warm air and the simple checks have not fixed it, you can book an evaporative repair in Perth and have a technician get it cooling properly again.