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Los Altos Hills AC Repair

The short answer

AC problems in Los Altos Hills homes often involve zone dampers, control boards or one of several systems rather than a single unit. We test each system and zone separately, fix the failed part, and check that the controls coordinate correctly.

When a home in Los Altos Hills loses cooling, it is often only part of the house. One zone stops responding, the upstairs system short-cycles while the main floor is fine, or a damper sticks and sends all the air to rooms nobody is using. Larger homes with multiple systems and zone controls have more moving pieces, and repairing them well means understanding how those pieces talk to each other. ReliableAir HVAC Services repairs air conditioning throughout ZIP 94022, about 11 miles west of our San Jose base. Here is what tends to fail in foothill homes and how we track it down.

Zoning faults that look like equipment failures

In a zoned house, each thermostat signals a central zone panel, which opens and closes motorized dampers in the ducts and tells the air conditioner how much to run. If a damper motor fails in the closed position, that area gets no air even though the outdoor unit is humming along. If a damper fails open, cool air spills into rooms that do not need it, and the zone that called for cooling never catches up.

We test each damper motor, check the zone panel's inputs and outputs, and confirm the bypass or static pressure control is working. A zoning problem caught early also protects the equipment, because a system that runs against closed dampers can freeze its coil or overheat its blower.

  • One area stays warm while others are comfortable
  • Air whistles loudly at certain registers
  • The system starts and stops every few minutes
  • Thermostats show a call for cooling but nothing changes in that zone

Outdoor units on hillside pads

Condensers at the edge of a wooded slope take a beating. Leaves, pine needles and dry grass blow into the coil; rodents look for shelter in the cabinet and chew low-voltage wire; and soil movement can tilt a pad until the unit vibrates or a line set rubs. We inspect the wiring, the coil surfaces and the base, and clean or correct what we find.

Electrical failures follow close behind. Weak capacitors, burned contactors and loose connections are the usual parts. We test each under load and look for the cause, such as high head pressure from a dirty coil, that may have shortened the part's life.

Long line sets and refrigerant charge

On large properties the outdoor equipment may be some distance from the air handler. Longer refrigerant lines hold more refrigerant and have more joints, so a small leak can take a while to show up as poor cooling. When a system is undercharged, we locate the leak first, using pressure testing and electronic detection, then repair it and charge by weight and measured superheat or subcooling. Topping off refrigerant without finding the leak is not a repair.

Air handlers in attics and crawlspaces

Hillside homes put air handlers in some unusual places: a crawlspace under a cantilevered wing, a tight attic above a vaulted room, or a mechanical closet on a lower level. Wherever the unit is, two things commonly cause trouble. The first is the condensate drain, which can clog and shut the system off through its safety switch or, in worse cases, overflow into the ceiling. The second is the blower, which can lose speed when its motor or capacitor weakens. We clear and test drains, verify float switches, and check blower amperage and airflow.

Deciding what to fix

In a home with three systems, it is normal for them to be at different ages. We look at each one on its own merits. A newer system with a failed part is an easy repair decision; a much older unit using R-22 refrigerant with a leaking coil deserves a frank conversation. If you do replace one, a heat pump is worth considering, since it also heats and aligns with the Bay Area Air District's direction for furnaces manufactured from 2029. The Air District rules do not require replacing equipment that still works.

Our AC repair technicians also cover Palo Alto, Los Altos, Mountain View, Cupertino and Sunnyvale.

More services in Los Altos Hills

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What to expect

How a visit goes

  1. Test, then talk

    Readings come first. You hear the cause of the problem and see the evidence before any part is replaced.

  2. Options, not pressure

    When repair and replacement are both reasonable, we lay out each path and let you choose the one that fits your home and plans.

  3. Respect for the house

    Shoe covers, drop cloths and a cleared work area. Attics, closets and side yards are left the way we found them.

FAQ

Common questions

Why is only one part of my house not cooling?

In zoned homes, a failed damper motor or zone control is a common cause. In homes with several systems, one unit may have failed while the others still run. We test each zone and system separately.

Can rodents damage my air conditioner?

Yes. Rodents sometimes nest in outdoor units and chew low-voltage wiring, which can stop the system from starting. We inspect and repair wiring and can suggest ways to discourage nesting.

My AC drain overflowed. What should I do?

Turn the system off and catch any dripping water. A clogged condensate line is the usual cause. We clear the line and verify that the safety float switch works.

Is it worth repairing an older R-22 system?

Electrical and mechanical repairs often are. Refrigerant leaks are harder because R-22 is no longer manufactured, so we compare repair costs with replacement options.

How do you find a refrigerant leak on a long line set?

We pressure-test the system and use electronic leak detection along the lines and at each fitting, coil and valve until the leak is located.

Tell us what your system is doing

Describe the noise, smell, error code or temperature problem, and we will set up a visit to find the cause and talk through your options.

(669) 666-6071
Call (669) 666-6071 Request Service