AC Not Cooling in Hillsborough

AC Not Cooling in Hillsborough

Hillsborough estates sit on big sloped lots under heavy tree cover, and most run more than one cooling system across the floors. The shade and elevation keep the cooling load light, rarely past the mid-80s. Because of that, a failed system can go unnoticed for a while. The shaded side of the house holds its temperature on its own, so you only catch the problem when one floor or wing climbs.

The terrain drives most of what we find here. Condensers set into hillside grade and ringed by trees pull leaves and needles into the coil until it cannot shed heat. Condensate lines that have to run downhill along the slope clog and back up, and a backed-up drain trips the float switch and shuts the system off. Those are the failures we see far more often in Hillsborough than in a flat-lot town, and both are clearable in a visit.

A warm floor here does not mean a failed system. We find which system serves it, clear the local obstruction if there is one, and separate a mechanical fault from a controls fault before quoting. A fouled coil, a clogged drain, a bad capacitor, or a leak on one circuit are all single-part repairs, and each goes on a written estimate with a price first.

Common causes

Debris-clogged condenser coil. Hillside lots under tree cover drop leaves and needles into the outdoor coil until it cannot reject heat, and that system loses cooling. We clean the coil thoroughly and check the fan motor, and we talk through placement or screening if one unit keeps fouling.

Backed-up condensate tripping a safety shutoff. Condensate lines that follow the downhill grade clog and back up, and the float switch shuts the system down so it stops cooling entirely. On these sloped lots it is one of the more common no-cool calls. We clear the line, test the float, and reroute the drain where the slope is the real culprit.

Failed capacitor or contactor on one system. With several systems per home, a bad capacitor or corroded contactor takes one wing or floor offline while the others run. We test the electrical components on the affected condenser and replace the failed part, usually same visit.

Stuck zoning damper. A zone damper that hangs closed starves a floor of cooled air even though the equipment runs. We check the damper actuators and zone board and restore airflow to the affected zone.

Refrigerant leak on one circuit. Weak cooling on a single system usually means it is low on refrigerant. We pressure-test that circuit, find the leak, and give you honest repair-versus-replace numbers for that system based on its age.

Frozen evaporator coil from low airflow. A clogged filter or restricted return ices the indoor coil and the system blows warm. We thaw it, fix the airflow restriction, and confirm the zone cools again.

How we diagnose it

• Determine which of the home's systems is affected and which floors or wings it serves.
• Inspect and clean the outdoor coil, which fouls fast under hillside tree cover.
• Check the condensate line and float switch, since downhill drain runs clog and shut systems off on these lots.
• Test the affected condenser's capacitor, contactor, and compressor start.
• Read refrigerant pressures on the affected circuit and check zoning dampers and the zone board for a stuck zone.

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

AC Not Cooling in Hillsborough: common questions

Nearby and related

AC Not Cooling near Hillsborough: Menlo Park · Palo Alto .

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