Cooling Guides
Evaporative Cooler Leaking Water? Causes, Checks and Fixes
Oct
An evaporative cooler leaking water is usually caused by a water valve that won’t close or seal: the float valve, the solenoid valve or the dump/drain valve. Less often it’s a split hose, a loose fitting or blocked pads. This guide helps you work out where the water is coming from, what the likely cause is, and which replacement part fixes it.
First: is it actually a leak?
Some water leaving the cooler is normal. Many coolers regularly drain or bleed off a small amount of water to flush out salts and minerals, and drain the tank completely when they switch off. This water runs out through the drain pipe on the roof.
It is a leak if:
- water keeps running from the drain or overflow when the cooler is off,
- water drips from the cooler cabinet, fittings or supply line,
- the tank keeps refilling and draining over and over, or
- water comes through the ceiling or out of the ceiling outlets inside the house.
If water is coming through your ceiling, turn the cooler off and turn off its water supply straight away. Wet plaster can be damaged quickly.
Find the cause from the symptom
| What you see | Most likely cause | Part to check |
|---|---|---|
| Water pouring from the overflow pipe while the cooler runs | Water level set too high, or a worn float valve that won’t shut off | Float valve |
| Water keeps running in with the cooler turned off | Solenoid valve stuck open, or a worn float valve | Solenoid valve, float valve |
| Water keeps draining away and the tank never fills properly | Dump or drain valve not sealing (worn washer or seal, or debris) | Dump/drain valve, seal or washer |
| Drips from fittings or the water supply line | Loose or cracked fitting, perished washer | Fittings, washers |
| Water spraying out of the louvres or cabinet | Blocked or collapsed pads, or a split pump hose | Pads, pump hose |
| Water coming out of ceiling outlets inside the house | Water being blown off saturated, clogged or collapsed pads | Pads, water flow setting |
Float valve problems
In coolers with a mechanical float valve, the float rises with the water and shuts off the supply at the right level. If the float is set too high, damaged or full of water, or the valve seat is worn, the tank overfills and water runs out of the overflow.
Check that the float moves freely and isn’t holding water. Small level adjustments are often possible, but a worn valve should be replaced. Float valves by brand:
- Bonaire and Celair float valves
- Breezair, Braemar and Coolair float valves
- Brivis float valves
- CoolBreeze float valves
Solenoid valve problems
Many modern coolers fill through an electric solenoid valve that opens when the cooler calls for water. If debris gets caught in the valve or its diaphragm wears, it can stay partly open and let water run in when the cooler is off. A solenoid that hums but doesn’t open, or won’t close, needs replacing.
- Bonaire and Celair solenoid valves
- Breezair, Braemar and Coolair solenoid valves
- Brivis solenoid valves
- CoolBreeze solenoid valves
Our float valve and solenoid guide covers both valves in more detail.
Dump and drain valve problems
The dump or drain valve empties the tank. If its washer or seal is worn, or grit stops it closing, water leaks away constantly. The cooler then keeps refilling, wasting water and sometimes never reaching full cooling.
Often only the seal or washer needs replacing, which is cheaper than a full valve. For example, Bonaire Aquamiser drain valves use the Aquamiser valve seal MK2, and the Bonaire dump valve comes with its washer.
- Bonaire and Celair dump valves and drain valves
- Breezair, Braemar and Coolair drain valves
- CoolBreeze dump and drain valves
See our drain valve guide for the different valve types and how to test them.
Pads, hoses and water flow
When pads are clogged with scale or have collapsed, water can’t soak through evenly. It runs down one area or gets blown off by the fan, which can push water out of the louvres or into the ducts. Replacing old pads usually fixes this. Read our cooler pads guide for when to replace them, or browse Bonaire and Celair pads, Breezair, Braemar and Coolair pads and Brivis pads.
Also check the hose from the pump to the water distribution system for splits, and that the water distributor isn’t blocked. If the pump itself is faulty, see our pump guide.
Safety before you start
- Turn off the power at the cooler’s isolation switch and the circuit breaker.
- Turn off the water supply to the cooler.
- Take care on the roof, and don’t work on it in wet or windy weather.
- Electrical repairs should be done by a qualified technician, and connections to mains water by a licensed plumber where required.
Frequently asked questions
Is it normal for my evaporative cooler to drain water?
Yes. Many coolers drain or bleed off water regularly to keep minerals down, and drain the tank when they switch off. Water running constantly while the cooler is off is not normal.
Why is my evaporative cooler overflowing?
Usually the float valve is set too high or worn, or the solenoid valve isn’t closing. Check the float first, then the solenoid.
Why is water coming out of my ceiling vents?
Water is usually being blown off clogged or collapsed pads. Turn the cooler off, then check the pads and the water flow. If the ceiling is wet, turn off the water supply too.
Can I fix a leaking cooler myself?
Replacing a float valve, washer or seal is a simple job for many handy owners, as long as the power and water are off. For electrical parts, or if you’re not comfortable working on a roof, use a qualified technician.
Not sure which part you need? Browse all evaporative cooler parts, or contact HotnCool with your cooler model and a photo of the leaking part and we’ll help you find the right replacement.
More evaporative cooler guides
- Evaporative cooler not cooling? Causes and fixes
- Float valve and solenoid guide
- Drain valve guide
- Celair evaporative cooler parts guide
- Evaporative cooler service checklist
