How to Replace an Evaporative Cooler Float Valve

Many evaporative coolers, especially older ones, control the water level in the tray with a float valve, much like a toilet cistern. As the water rises, the float lifts and shuts off the supply. When the seal hardens or the float sticks, the tray overflows or doesn’t fill. It’s one of the cheapest cooler parts and one of the easiest to replace.

Signs the float valve has failed

• Water runs constantly from the overflow or drain while the cooler is on
• The tray fills too high or too low
• The tray doesn’t fill at all, even though the solenoid opens
• Dripping from the valve when the cooler is off

If the tray overflows, first check the float isn’t just stuck on scale. If it moves freely and still won’t shut off, the valve needs replacing. See also cooler overflowing or water running constantly.

Which float valve do you need?

• Breezair, Braemar and Coolair: the vertical float valve (901114) or the Braemar adjustable horizontal float valve (905150)
• Brivis: Philmac float valves under part number B000414, with a float assembly, straight arm or cranked arm, and a replacement float bulb (B000415)
• Bonaire: the cistern float ball valve (6050916SP)
• Older CoolBreeze and other coolers: the Fluidmaster 747 float valve. Newer CoolBreeze units use a magnetic float switch instead.

Match the arm shape and mounting to your old valve. If in doubt, send us a photo.

Replacing the float valve

1. Turn off the cooler at the controller and isolator, and turn off the water supply.
2. Drain the tray, or bail it out until the valve is above the water.
3. Undo the water supply fitting to the valve, then the locknut holding the valve to the cabinet.
4. Fit the new valve with its washers, tighten the locknut firmly (don’t overtighten plastic threads) and reconnect the water supply.
5. Turn the water on and let the tray fill. Check for leaks at the fittings.

Setting the water level

Adjust the float arm or level screw so the water stops just below the overflow, or at the level shown in your cooler’s manual. Too high wastes water through the overflow. Too low can starve the pump.

Shop float valves

Browse all evaporative cooler float valves, or send us your cooler model and we’ll confirm the right valve.

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