Condensate Leak in the Attic in Mountain View

Condensate Leak in the Attic in Mountain View

A lot of Mountain View housing, especially the 1940s through 60s homes around Old Mountain View, was built with heat only and no central AC. As warming summers and daytime remote work changed the math, owners added cooling, often a condenser-and-coil tied onto the existing furnace in the attic. Those retrofit coils produce condensate the original system never had to handle, and the drain that came with them is sometimes an afterthought. That is where the leak starts.

Mountain View summers stay mild, design cooling around 88 degrees with a real marine layer most mornings, so AC runtime is moderate. That works against you on condensate the way it does elsewhere. A drain that only sees water in short bursts can hide a partial clog for weeks, then overflow the emergency pan the first hot stretch. On a retrofit install the float switch and secondary pan may have been added correctly, or may have been skipped to save time. We find out which.

The fix is almost always a single part. A clogged line gets cleared and flushed. A missing float or a failed condensate pump is cheap. The expensive case is the one that ran unseen and soaked the ceiling. We diagnose the real cause before quoting, and on retrofit coils we pay extra attention to whether the drain was done right in the first place. The $75 diagnostic gets credited toward the repair if it runs over $200.

Common causes

Retrofit coil with an undersized or poorly routed drain. AC added onto an old furnace sometimes got a drain line that was easy to run rather than correct. We trace the whole run, confirm it is properly trapped and pitched, and re-route or re-trap it when the original install cut corners.

Primary drain line clogged with biofilm. Moderate runtime still grows algae in the line, and the clog sits until a hot stretch overflows it. We vacuum at the termination, flush from the coil, and verify a clean continuous run.

Condensate pump failure on a low attic handler. Where the attic coil cannot drain by gravity, a small pump moves the water. A stuck float or dead motor sends the reservoir over the top. We test the pump by filling it and confirming it switches on and discharges, then replace it if it is done.

Missing float switch on a retrofit install. Fast AC add-ons sometimes skipped the safety float entirely. With no switch, a clog has nothing to stop it before the ceiling. We check for one, test it, and write the cost of adding it into the estimate when it is absent. It is the cheapest part on the system.

Cracked or improperly seated primary pan. A coil pan that cracks or was never seated level lets water bypass the drain. We inspect it directly and re-seat or replace it so the water actually reaches the drain.

How we diagnose it

• Determine whether the attic coil is a retrofit and how its drain was originally routed, including trap, slope, and termination.
• Find whether the unit drains by gravity or through a pump, and test the pump if there is one.
• Confirm a float switch is present and actually shuts the system down when triggered.
• Vacuum and flush the primary line, then watch for a clean run at the termination.
• Inspect the primary and secondary pans for cracks and proper seating.

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

Condensate Leak in the Attic in Mountain View: common questions

Nearby and related

Condensate Leak in the Attic near Mountain View: Palo Alto · Los Altos · Sunnyvale .

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