Condensate Overflow Safety Switch is easily installed in the drain line to detect downstream clogs and interrupt the thermostat circuit to shut off the unit before flooding occurs. The switch can also be installed to activate audible and/or visual alarm circuitry. The FSF comes complete with a 1" × 3/4" reducing bushing and a 3/4" plug for auxiliary drain pan outlets. The switch/holder assembly is easily removed to enable cleaning of any clog in the line. float level switches for low pressure system, named as Condensate Overflow Safety Switch installed in the drain line to detect downstream clogs.