AC Leaking Water in Mountain View

AC Leaking Water in Mountain View

AC leaking water almost never means the system is dead. It means water the unit is supposed to drain away is going somewhere it should not. Your evaporator coil pulls moisture out of the air every time it runs, and that water collects in a pan and exits through a drain line. When the line clogs or the pan cracks, the water backs up and shows up below the unit.

Mountain View has a particular version of this. A good share of the older Old Mountain View housing started out heat-only, and AC got retrofitted later by adding a coil and condenser to the existing furnace. When that furnace and coil sit in the attic or a hallway closet, the condensate drain is often a long, low-slope run that was the easiest path during the retrofit, not the best draining one. Over a few years it silts up with algae and dust, the pan overflows, and the first sign is a brown ring on the ceiling.

These systems run intermittently in the Peninsula climate, so a slow clog can sit unnoticed for weeks before you see anything. The fix is almost always a single part or a clean-out, not a new system.

Common causes

Clogged condensate drain line. This is the most common cause we find. Algae and dust build up in the drain line and water backs up into the pan and over the edge. We clear the line with a vacuum at the termination and flush it, then confirm flow by pouring water through the pan. On retrofitted Mountain View attic units we often add or correct the trap so it stops re-clogging.

Overflowing or rusted-through drain pan. Older retrofit coils sit on a metal pan that eventually rusts, or a secondary plastic pan that cracks. Water pools and drips through the ceiling. We inspect both pans, and if the primary pan is corroded we price a coil-and-pan service on the estimate rather than patching rust that will fail again.

Float switch missing or failed. An attic air handler should have a float switch that shuts the system off before an overflow reaches your ceiling. On a lot of older retrofits there is no switch at all, or the one installed has stuck. We test it, and if there isn't one we recommend adding it. It is a cheap part that prevents an expensive drywall repair.

Frozen coil that melts after shutdown. If the system is low on refrigerant or airflow is choked by a dirty filter, the coil ices up while running, then dumps a flood of water when it shuts off. We check refrigerant charge with gauges and inspect the filter and blower. The leak is a symptom here. The real fix is the charge or airflow problem behind it.

Disconnected or sloped-wrong drain line. Retrofit drain lines added during an AC conversion sometimes lose their downhill slope as framing settles, or a fitting works loose in the attic. Water exits the joint instead of the drain. We trace the full run, re-slope or re-secure it, and verify it drains under a load test.

How we diagnose it

• Locate the air handler (attic or closet) and inspect both the primary and secondary drain pans for standing water, rust, and cracks.
• Pour water through the pan to confirm the drain line actually carries it away, then clear and flush the line if it backs up.
• Test the float switch, or note its absence, and confirm it cuts the system off when the pan fills.
• Check the filter, blower, and refrigerant charge to rule out a frozen coil as the source of the water.
• Put the findings and the fix on a written estimate before any work, with the $75 diagnostic credited toward repairs over $200.

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

AC Leaking Water in Mountain View: common questions

Nearby and related

AC Leaking Water 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.