AC Leaking Water in San Ramon

AC Leaking Water in San Ramon

San Ramon gets real summer heat, 95-plus is common in July and August, so AC here carries a heavy load and runs for hours at a stretch. A system working that hard pulls a lot of moisture out of the air, and that water has to drain somewhere. When the drain path fails, the leak shows up fast, and in two-story homes it often shows up as a stain on a ceiling below an attic air handler.

This is our home city, the shop is at Bishop Ranch, so we see a lot of these. The reassuring part stays true: water around the unit is almost never a dead system. It's the condensate side failing while the compressor and coil keep doing their job. That's why people miss it. The AC still cools while it quietly leaks.

A lot of San Ramon's 1980s and 90s tract homes are now at the age where original pans rust and drain lines have two decades of buildup in them. Newer subdivisions more often run dual-zone equipment, which means more drain runs that can fail. Either way the fix is a part, not a replacement, and we put it in writing first.

Common causes

Clogged primary condensate line. Heavy summer runtime plus twenty years of buildup plugs the drain line. The pan overflows and, on an attic unit, drips down to the ceiling below. We clear and flush the line, confirm the secondary drain and float switch, and add a cleanout if the install lacks one.

Float switch missing or stuck. The float switch shuts the system down before the pan overflows. Older tract installs often skipped it, and on a dual-zone system a float can stick on the zone you run less. We test by filling the pan and add or replace the switch so a clog stops the system instead of soaking the ceiling.

Rusted or cracked drain pan. On the 1980s and 90s systems that make up a lot of our San Ramon work, the secondary pan rusts through after 20-plus years. Water bypasses the drain entirely. We dry, run, and confirm the leak originates at the pan before replacing it.

Frozen evaporator coil melting off. A dirty filter or a low refrigerant charge ices the coil during a long hot afternoon, then it melts and overwhelms the pan after the system cycles off. We check filter and airflow and read the charge before assuming the drain is the only fault.

Condensate pump failure. Some San Ramon installs, especially where the unit sits below the drain point, rely on a condensate pump. When the pump dies the reservoir overflows. We test the float in the pump and the check valve, and replace the pump if it's failed.

How we diagnose it

• Trace the leak to its source at the air handler, particularly on attic units where the ceiling stain is offset from the equipment.
• Clear and flush the primary condensate line, and add a cleanout tee for future service.
• Test the float safety switch by filling the pan, and add or replace it as needed.
• Inspect both drain pans for rust-through and cracks on older tract-home systems.
• Check the filter, coil, refrigerant charge, and any condensate pump to rule out a frozen coil or pump failure.

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

AC Leaking Water in San Ramon: common questions

Nearby and related

AC Leaking Water near San Ramon: Danville · Alamo · Dublin · Pleasanton .

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