SOS-1 – FLOAT SWITCH

DiversiTech Asurity solid-state condensate overflow safety switch. It clamps onto a 3/4″ PVC drain line and senses a near-full pipe without cutting into it, then opens the 24 VAC circuit to the compressor contactor so the coil stops making condensate. It latches: the yellow LED stays on and the compressor stays off until the blockage is cleared and power is cycled. Wire it into the thermostat Y circuit only.

Specifications published by the manufacturer. Source: manufacturer documentation.

Specs

• ManufacturerDiversiTech (Asurity)
• TypeSolid-state condensate overflow safety switch, no moving parts
• ContactsNormally closed; opens the compressor contactor circuit on detection
• Power24 VAC control circuit, Class 2 wiring
• Current capacityContactor coils requiring up to 1.25 A
• Application3/4" SCH 40 or PSI-200 PVC drain lines
• IndicatorYellow LED indicates moisture detected
• ResetLatching - remove power, clear the obstruction, re-apply power
• WiringIn series between thermostat Y and the compressor contactor

Cross-reference numbers

This part replaces the following OEM and aftermarket numbers:

• STANDEXSS3
• CS-3

Not sure if your number matches? Call (214) 340-9421 or bring the old part in — bench-testing is free.

What does a condensate float switch do?

It is a normally closed switch in the 24 volt control circuit that opens when water rises. The primary switch goes in the drain line at a tee or in the primary pan. The secondary sits in the emergency pan under an attic air handler. When it opens, the system stops making condensate before the pan overflows into your ceiling.

My AC quit in the middle of a hot week. Could this be it?

Very possibly, and on a Dallas attic unit it is one of the first things to check. Our cooling season runs most of the year, drains grow algae, and a slow trap or a flat run of PVC is all it takes. If the thermostat went blank, the switch is probably breaking R. If the blower runs and the outdoor unit does nothing, it is probably breaking Y.

Should mine break R or Y?

Breaking R shuts the system down and blanks the thermostat, so the problem gets noticed immediately and the coil stops sweating. Breaking Y stops the compressor but leaves the blower running, which in DFW humidity can re-evaporate pan water right back into the house. Most people here are better off breaking R. If you have more than one float switch, wire them in series.

Can I bypass it until I get the drain cleared?

No. Clear the drain. A jumper across a float switch is how a stained ceiling turns into a drywall job.