RectorSeal Safe-T-Switch 97637 Condensate Overflow Switch, Easy Access, Condensate Drain Shut Off System, Magnetic Reed Switch, HVAC, Includes 3/4" Adapter

This is a typical safety switch and is used to shut off an A/C unit when the evaporator condensate drain is clogged. The Rectorseal brand is a common brand. It is usually installed on the secondary drain port on the indoor evaporator coil or the air handler. It has a float that opens a switch so you wire it in series to the yellow thermostat wire (24 volt wire) to shut off the outdoor compressor if it senses the evaporator pan is overflowing. I like to pressure fit the PVC connection so you can remove it from the coil instead of glueing it in place. The pipe size is 3/4". I would use a different type float switch (clamp-on type) on the emergency drain pan under the furnace or air handler. I think it is better used close to the evaporator because a condensate leak will leak through a furnace and ruin a main circuit board or even a blower motor before a lower emergency pan float switch shuts off the air conditioner. Remember it is for 24 volt circuits. Install it "inline" or in series on the thermostat wire that energizes the compressor- usually the yellow"Y" wire. This means the blower (G(reen))wire will still run. Make sure you install it level with the evaporator on the secondary drain port which is slightly HIGHER then the main drain port on a evaporator which should already have a white PVC pipe connected. Do not disable this safety- fix the clogged pipe - use a wet vacuum on the condensate drain pipe outside that usually works. You can also cut the drainline near the indoor coil and use pressurized nitrogen to blow out a clog then use a 3/4" PVC coupling to reconnect the drainline. Make sure to clear the pipe going into the coil as well. All air handlers should have a PVC ptrap on the drain pipe this keeps the blower from drawing air in through that drainline and possibly keeping the drain from draining. On a regular gas furnace the indoor coil is on the "positive" side of the blower so it doesn't need the p-trap -(it blows a little air outward through that drainline). Sometimes the secondary drain port on the evaporator has a plug or a plastic knockout I carefully use a drill bit to drill through the knockout without damaging the threads. This threaded connection just needs to be hand tightened plus maybe a 1/2 turn don't overtight these drain connections on the coil as the pan is usually plastic and can crack. Use tfe paste or teflon tape on the threads. You should be able to lift the float assembly out of the elbow to clean it when needed. The quality of this product is good and it is a simple product. You can easily test it like any switch using a volt meter while the outdoor compressor is running it should have 24 volts between either of the wire leads to ground. With the switch open (overflow position) one lead would read 24 volts and the other lead 0 volts to ground- that is while thermostat is "calling for" the compressor to run. Some service techs install this on the 24 volt red wire which will switch off all the 24 volts to the thermostat just have to trace the 24 volt wiring to know. A furnace or airhandler in an attic should always have a emergency drain pan under it on the floor and that pan should always stay dry except if there is a problem. Shut off the unit if that emergency pan has water in it until the leak is fixed. This switch is used mostly if the unit is in a closet or in the garage or basement and can be used along with the emergency pan. Almost all Air conditioner drains clog up eventually. A heat pump doesn't produce condensate in the indoor section in the heating (winter) mode just in the A/C (summer) mode.

Perfect replacement for a faulty AC unit that loved to trigger an alarm at 2am. I picked up two of these to future proof any issues. A simple snip and splice of the wires and we are back up and running. Perfect for our need and a great value considering the alternative is a 2am alarm.

THe perfect replacement for my air handler drain. It funtions as advertised.

great price and simple to understand . saved over 60.00 if done by a/c tech

This switch installs easily and works perfectly.

tengo instalado varios y al parecer todo va bien,parece confiable

Perfect! It got my AC up and running again! I had the Nest E195 error and it was a defective float and not just a clogged line.

Replaced existing float switch with ease