AC Leaking Water in San Jose

AC Leaking Water in San Jose

San Jose summers run hot, regularly into the 90s for long stretches, so AC here works for months at a time. A system that runs that hard pulls a lot of humidity out of the air, and all of that water has to go somewhere. When the drain path fails, you don't get a slow coastal drip. You get a steady leak that shows up fast as a brown ring on the ceiling below an attic air handler.

The good news is the same as everywhere: water around the unit almost never means the AC is dead. It means the condensate side has a problem, the pan or the drain line or the safety switch. The compressor and coil are usually fine. We see this most in two-story homes where the air handler sits in the attic, because gravity works against a long horizontal drain run up there.

San Jose's housing mix matters here. Older Eichlers and homes on ductless mini-splits leak from a different spot, the indoor head's drain or a condensate pump, while ducted homes leak from attic pans and primary drains. We diagnose to the equipment in front of us, whatever it turns out to be.

Common causes

Clogged primary drain on an attic air handler. The high-volume San Jose summer failure. A heavy cooling load means lots of condensate, and a plugged primary line backs up into the pan and over the edge onto the ceiling. We clear and flush the line, confirm the secondary drain and float switch work, and add a cleanout if there isn't one.

Float switch missing or stuck. The float switch should cut the system off before the pan overflows. On older attic installs it's often absent, and on newer ones the float can stick. We test it by filling the pan, and replace or add it so a clog becomes a no-cool call instead of ceiling damage.

Ductless mini-split drain or condensate pump failure. On a mini-split, the wall head drains through a small line, sometimes assisted by a condensate pump. A kinked line or a dead pump leaks down the wall. We clear the line or replace the pump, and re-secure the drain run so it stops happening.

Frozen evaporator coil melting off. A dirty filter or low refrigerant charge ices the coil while the system runs all afternoon. After dark it melts and overwhelms the pan. We check filter and airflow first, then read the charge on gauges before touching the drain, because the drain isn't the real fault here.

Cracked or corroded drain pan. On 20-plus-year systems the secondary pan rusts through. Water bypasses the drain completely. We dry everything, run the system, and confirm the leak originates at the pan before replacing it.

How we diagnose it

• Trace the leak to its source at the air handler, especially on attic units where the stain appears a room away from the equipment.
• Clear and flush the primary condensate line, and add a cleanout tee if access is poor.
• Test the float safety switch by filling the pan, and add or replace it as needed.
• On mini-splits, check the head drain line and condensate pump for clogs or failure.
• Read refrigerant charge and check the filter to rule out a frozen coil as the water source.

$75 diagnostic, credited toward any repair over $200. You get a written quote before any work begins.

AC Leaking Water in San Jose: common questions

Nearby and related

AC Leaking Water near San Jose: Santa Clara · Milpitas · Cupertino .

This is usually a ac repair in San Jose job. See our ac repair overview or the San Jose service area.