The water level in a swamp cooler is regulated by a simple float valve that sits inside the unit. When the float valve is not working properly, the swamp cooler can overfill and leak out of the sides or through the overflow release. A leak can result in several gallons of wasted water per week. This is a fairly common problem because swamp cooler float valves are often cheaply made and may last only a season or two. But replacing one is an easy and inexpensive project that you can certainly do yourself.
The cost of a new float valve can vary quite a bit, but even the best models are not very expensive. It's best to purchase a valve in the mid-range or better. Low-end valves tend to be hard to adjust to the correct water level and usually don't last as long as better valves.
Before You Begin
Shut off the water supply to the swamp cooler. There should be a dedicated valve on the unit's cold water supply line; if not, shut off the water to the house at the main shutoff or at the water meter.
Equipment / Tools
- Two pairs of pliers or wrenches
- Penetrating lubricant (optional)
- Replacement float valve
Open Up the Swamp Cooler
Remove the access panel on the side of the swamp cooler to gain access to the float valve and water line. You may have to remove more than one panel.
Disconnect the Water Supply Line
Disconnect the water supply line by removing the 1/4-inch nut connecting the supply line to the float, using pliers or a wrench. You may have to hold the valve while you loosen the nut, so the valve doesn't turn. Once the nut is loose, pull the line straight out of the float valve.
Remove the Old Float Valve
Hold the valve with one pair of pliers and remove the housing nut with a second pair. If the valve has been in place for a long time, it might be corroded, and the nut won't budge. If so, spray it with a penetrating lubricant (such as WD-40) and let it sit for a few minutes before loosening it.
When the nut is removed, pull the valve out of the swamp cooler.
Install the New Float Valve
Install the new float valve in the same position as the old one. As you tighten the nut, make sure that the float will go up and down perpendicular to the water level. You may have to hold the float valve in place and tighten the nut at the same time, so the valve doesn't turn.
If there is a gasket with the new valve, place it as directed by the valve manufacturer, or follow the original installation.
Make Sure the Valve Works
Reconnect the water supply line to the float valve. Turn the water supply back on and check the 1/4-inch nut for leaks. If there is a leak, that means the nut is not tight enough. Hold the nut against the valve with pliers and give it another quarter-turn until the leak stops.
Adjust the Float
Adjust the float so that the water level is where you want it to be. Make sure the water level is high enough to cover the pump suction area easily; if it's too low, the pump will burn out.
Reinstall the access panel(s). The unit should be ready for use.
It's a good idea to check the water level the next day to make sure it's still where you want it to be. If it's not, check the valve again.