AC Not Cooling in Los Gatos

AC Not Cooling in Los Gatos

An AC that runs but will not cool is rarely a dead system. The compressor and blower usually outlast everything else. What fails first is a capacitor, a contactor, the refrigerant charge after a slow leak, or airflow that drops until the coil freezes solid. We measure the system's actual performance with gauges before we call a cause, because the wrong guess here is expensive.

Los Gatos makes the diagnosis trickier than most cities. The hillside homes carry a heavy afternoon cooling load. A west-facing master on an upper floor can be calling for cooling hard at 4 PM while the shaded lower level is still comfortable. When one zone never cools, the system is not always broken. Sometimes a single-zone setup is simply losing the afternoon fight against sun and elevation. Other times a real part has failed on top of it. We separate the two so you fix the right thing.

Downtown is a different world. Many of the older homes have no central AC at all, just wall units or a window unit doing the work. When those quit, the conversation is usually about adding proper cooling without tearing into plaster, not repairing a system that was never really there. We will tell you which situation you are in before any work.

Common causes

Failed run capacitor. The most common reason an AC runs but blows warm. The capacitor starts the compressor and fan motors, and heat wears it out. We meter it on the spot, and if it is weak we swap it from the truck, usually $150 to $250, and the system cools again the same visit.

Low refrigerant from a leak. Low charge means the coil cannot absorb heat, so the air comes out warm. Refrigerant is not consumed, so a low system is a leaking system. We locate the leak instead of topping it off and walking away. On older R-22 hillside installs a confirmed leak usually tips the math toward replacement, and we show you the numbers.

Single-zone system losing the afternoon load. On a larger hillside home, one zone trying to cool a west-facing upper floor and a shaded lower floor at the same time will lose every afternoon. That reads as an AC that cannot keep up but tests out mechanically fine. The fix is usually zoning or a supplemental ductless head for the worst rooms, and we lay out the cost at the estimate so you can weigh it.

Frozen evaporator coil. Weak airflow from a clogged filter or a restricted return ices the indoor coil, and once it is a block of ice the vents blow warm. We thaw it and trace the airflow restriction to its cause rather than just changing the filter and hoping. We confirm it is fixed before we leave.

Dirty condenser coil. Hillside units collect leaf litter, dust, and oak debris in the coil. A fouled coil cannot dump heat outdoors and the house stays warm while the system runs. Cleaning the coil is cheap to rule out first and often restores most of the lost capacity on its own.

Worn contactor. The contactor switches the outdoor unit on. When its contacts pit and stick, the condenser may never start while the indoor fan keeps pushing warm air. We test it and replace it from stock when the readings call for it.

How we diagnose it

• Refrigerant pressures and subcooling with gauges to confirm whether the charge is actually low or the issue is elsewhere.
• Capacitor and contactor tested electrically before anything goes on the estimate.
• Temperature split room by room and floor by floor, which on a hillside home tells us if this is a failed part or a zone losing the afternoon sun load.
• Evaporator coil and filter checked for icing and airflow restriction.
• Condenser coil inspected for oak and leaf debris common on wooded hillside lots.

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

AC Not Cooling in Los Gatos: common questions

Nearby and related

AC Not Cooling near Los Gatos: Saratoga · San Jose · Cupertino .

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