San Antonio · Float Switch Replacement Repair · Family-Owned Since 1996
A float switch shuts down your AC when the condensate drain backs up — before water can flood your attic and crash through your sheetrock. If yours is tripping, the drain needs cleaning. If you don't have one, you need one.
Typical price
$149–$249
Time to fix
45–75 minutes
Urgency
High — without it, a clogged drain floods your ceiling
When your AC runs, the indoor coil produces a steady stream of condensation. That water drips into a pan and flows out through a 3/4-inch PVC drain line. When that line clogs (algae, dust, biofilm) and the pan fills up, you have two possibilities: the float switch trips and shuts the system off, or you don't have one and the water keeps coming until your bedroom ceiling collapses.
Texas code requires a float switch on any AC installed in an attic or above finished living space. We install them on every job. They're cheap ($25–$80 part), reliable, and they're the single best protection against water damage from a $200 problem turning into a $15,000 ceiling repair.
$149 to install a new float switch where there isn't one. $189 if you also need the drain line flushed (which is usually why the float tripped in the first place). $249 if your secondary drain pan is also rusted out and needs replacement.
What it costs in San Antonio
$149–$249 — Includes new float switch, drain line flush, system test. Required by Texas code on attic installs. Our $59 diagnostic is waived when you approve the repair, so you only pay for the fix itself.
If two or more of these sound familiar, it's probably your float switch replacement.
Here's exactly what a Carnes and Sons tech does at your house — no mystery, no upselling.
There are usually two — one in the primary drain pan, one in the secondary 'safety' pan under the air handler. We check both for proper function.
Vacuum from the outside cleanout to pull the clog through. Sometimes nitrogen purge is faster. We add biocide tablets to prevent re-clogging.
Look for rust, holes, standing water. If the pan is shot, we replace it (drywall ceiling stains below the air handler are almost always from a failed secondary pan).
Install a quality SS2 or condensate overflow switch wired into the 24V control circuit. Test by lifting the float — system should shut off within seconds.
Get Your Float Switch Replacement Diagnosed Today
Tell us what's happening. We'll text you back in minutes — no call center, no robo-calls.
A small device installed at your AC drain that shuts off the system if the drain backs up. Required by Texas code on any attic install. Prevents the kind of water damage that ruins ceilings and costs $10,000+ to repair.
Most often it's the float switch tripping because the condensate drain is partially clogged. The float is doing its job. The fix is flushing the drain line and (if water came back) installing a fresh float switch.
$149–$249 in San Antonio. Includes new float switch, drain line flush, and full system test. Compare to a $15,000 ceiling collapse — easiest decision you'll make this year.
If you're handy with PVC plumbing and 24V low-voltage wiring, yes. Most homeowners shouldn't — the wiring has to be in series with the thermostat 24V circuit, and wrong wiring just bypasses the protection.
Annually as part of a tune-up. More often in homes with pets, smokers, or dirty filters. Biocide tablets in the drain pan slow regrowth.
Older attic installs sometimes skipped it. Texas code now requires one. We can add a secondary pan with float switch on most installs for $349–$549.
Most are wired only into the cooling circuit — they trip on AC drain overflow. We can wire them to shut off both modes if you want.
Once a year: with the AC running, gently lift the float arm. The unit should shut off within a few seconds. If it doesn't, the switch is bad or wired wrong.
We're based in Stone Oak and roll trucks across San Antonio and the surrounding Hill Country every day.
License TACLB29435E · Family-Owned Since 1996
Cities & neighborhoods we serve
San Antonio · Stone Oak · Alamo Heights · Hollywood Park · Hill Country Village · Shavano Park · Castle Hills · Leon Valley · Helotes · Boerne · Fair Oaks Ranch · Bulverde · Timberwood Park · Garden Ridge · Schertz · Cibolo · Selma · Universal City · Live Oak · Converse · Windcrest · New Braunfels
No call center. The owner or one of his sons picks up.
(210) 600-5091