By James Marr.
Evaporative coolers (swamp coolers) cool a room or building by pulling air through wet pads. They work best in a dry climate, but provide some help even in north Alabama summers. The cooler pumps water from a reservoir to a gutter above the pads, where the water can run down and soak the pads. Excess water goes back into the reservoir. The reservoir is refilled from a water line with a float valve controlling the level. A toilet valve would probably work on a building-size cooling tower, but a smaller float valve is used for room units.
The small valve consists of a fixed opening for water input, a movable arm with a float on one end and a plug on the other end, and a pivot rivet.
As the water rises, the float rises, the arm pivots, the plug blocks the water opening, and the water flow stops. As water evaporates in the pads, the level drops and water flows again.
The float valve in my cooler fell apart at the pivot. The pivot hole in the arm was made by flattening the round stock and drilling a hole. The forces on the float and the plug result in more rapid wear on the side toward the plug. Good design would be to put the hole in the middle or on the side opposite the wear surface. The hole in this arm was close to the wrong edge. The metal was eventually too weak to hold the pin, so the assembly fell apart and water ran continuously.
The cooler manufacturer has gone out of business. The internet greenhouse supply company that sold the cooler has no idea where to get parts or even replacement pads (needed annually); their customer service person owns a cooler too. The local HVAC people have heard of a swamp cooler and suggested two local sources to try. One had a food-grade ice machine unit for $40 that could be used with some plumbing changes. The local branch of a national chain (Grainger) had a plug-compatible replacement unit made for an evaporative cooler for $8 with 4-day delivery. I’m considering buying a spare at that price.