Many air conditioning systems are designed with a float switch. Also known as an overflow switch, it’s designed to prevent water from spilling over the top of the condensate pan. Because it’s located near the evaporator coil, though, the float switch often goes unnoticed by homeowners. It’s not until a problem occurs with the float switch that homeowners begin to take notice.
What Is a Float Switch?
A flow switch is a small device that automatically shuts down the air conditioning system with which it’s used when the water reaches a certain level in the condensate pan. Like all switches, it controls a circuit. The float switch will open the circuit as the water level rises, thereby shutting down the air conditioning system.
How Float Switches Work
When inspecting your air conditioning system’s evaporator coil, you may notice a metal pan directly below it. This is the condensate pan. As the name suggests, it’s designed to catch condensation. Airborne moisture will condense on the evaporator coil, after which it will drip into the condensate pan.
At the bottom of the condensate pan is a drain that runs to your home’s exterior. Normally, water will travel through this drain and exit the condensate pan. There are instances, however, in which the drain may become clogged. Mildew buildup can result in a clogged drain. The moist environment encourages the growth of mildew-causing fungi within the drain. Regardless, the water level will continue to rise in the condensate drain if the drain is clogged – unless there’s a functional float switch in place.
The float switch is designed to prevent water from spilling over the top of the condensate pan. Upon reaching a high enough level on the condensate pan, the water will activate the float switch. The float switch will detect the presence of the water, at which point it will shut off the air conditioning system.
Do All AC Systems Have a Float Switch?
While they play an important role in protecting against water damage, not all air conditioning systems have a float switch. Many residential air conditioning systems are designed without them.
If your air conditioning doesn’t already have one, you may want to add a float switch. It will give you peace of mind knowing that water won’t spill over the top of the condensate pan. Even if the drain is clogged, the float switch will simply shut off your air conditioning system. Once turned off, your air conditioning system will no longer produce condensation at the evaporator coil.