Evaporative Cooling Service: What Actually Needs Doing Before Summer

An evaporative system loses performance long before it stops running, which is why so many people conclude their unit is finished when it is really just overdue. Spring is the time to deal with it — the first genuinely hot week is when every installer in the region is booked out.

What a proper service covers

**Pads.** These do the actual cooling, and they degrade. Mineral scale builds up, airflow through them drops, and the temperature drop the system can deliver falls with it. Aspen pads generally need replacing every couple of years depending on water quality; rigid media pads last considerably longer but still need inspection and cleaning.

**Water distribution.** The pump, the distribution tubes and the spreaders all need to be delivering water evenly across the full face of the pads. Blocked spreaders leave dry patches, and a dry patch is pad area doing nothing.

**Bleed-off.** Evaporative systems deliberately dump a small amount of water to stop dissolved minerals concentrating in the tray. If bleed-off is blocked or has been disabled, scale accumulates rapidly and shortens the life of pads, pump and tray alike.

**Float valve and tray.** Water level set correctly, no leaks, no rust, no sediment sitting in the bottom.

**Fan, belt and bearings.** On belt-drive units the belt tension and condition matter, and worn bearings announce themselves as noise well before they fail. Direct-drive units skip this but still need the fan and motor checked.

**Controller and wiring.** Fan speeds, pump operation, vent operation where fitted, and any fault codes.

**Winter cover.** If the unit has been covered for winter, the cover comes off and the system is run and checked before you actually need it.

The faults worth catching early

Weak or warm air is usually pads, water distribution, or a fan speed issue rather than a dead machine. A musty smell almost always means stagnant water in the tray or pads that have gone too long. Water in the ceiling is a leaking tray, a blocked drain or a failed float valve, and it will not fix itself. Noise is normally bearings or a belt.

None of those are exotic and most are cheap to fix at service time. All of them get considerably more expensive if you wait until they cause damage.

What you can check yourself

Look at the pads if you can access them safely — heavy white scale means they are due. Run the system before the season starts rather than discovering a fault on a forty-degree day. Listen for new noise. Check the ceiling around outlets for staining.

When servicing is not the answer

One honest caveat. If your complaint is that the system delivers warm damp air on humid days, servicing will not change that. Evaporative cooling depends on how much moisture the air can still absorb, and on a muggy afternoon that capacity simply is not there. That is a limitation of the technology rather than a fault, and no amount of maintenance will resolve it.

If that is your experience of the last few summers, the conversation worth having is about refrigerated cooling — either a changeover or, if you have gas ducted heating already, add-on cooling. If it is not, a well-maintained evaporative system is a cheap and effective way to cool a house in this climate, and there is no reason to replace it.