Carrier was founded in 1915 by Willis Carrier, the engineer credited with inventing modern air conditioning, and the name now covers central air conditioners, gas furnaces, heat pumps and ductless systems. In Novato, San Anselmo and Larkspur we see the whole range, from a single-stage AC paired with an older furnace to a communicating Infinity system. Whatever the model, most Carrier repairs come down to one failed part, an airflow problem or a control fault.
Single-stage, two-stage or Infinity?
The equipment level changes what the technician looks for first.
- Single-stage systems run at full output or not at all, under an ordinary thermostat. Parts are mostly standard: capacitors, contactors, fan motors, igniters and flame sensors.
- Two-stage systems run on a low stage most of the time and switch to high on hot or cold days. A thermostat that is not wired or set up for staging is a common reason they feel weak.
- Infinity systems use variable-speed technology and a communicating wall control. The control logs faults and component readings, so diagnosis starts there; some boards, drives and motors are specific to the model and may need to be ordered.
When the house will not cool on a hot afternoon
Inland Marin can be cool in the morning and hot by mid-afternoon, and that is when a marginal Carrier AC gives up. The usual reasons, roughly in the order we check them:
- Airflow. A dirty filter or indoor coil starves the system; the coil can freeze and cooling drops away.
- The outdoor coil. Leaves, dust and plant growth pack the fins, and the unit cannot shed heat when it is hottest.
- Electrical parts. A weak run capacitor or a pitted contactor can let the unit start in the morning and fail in the afternoon heat.
- Refrigerant. A low charge always means a leak somewhere; the leak is found before refrigerant is added.
- The compressor. Tested last, and condemned only after its start circuit and windings have been checked.
Our AC not cooling page lists what you can check yourself before calling.
Uneven rooms and leaky ducts
Inconsistent heating or cooling in a Carrier system often has nothing to do with the equipment. A thermostat in the wrong spot, a closed or broken damper, or a duct that has come apart in the crawlspace leaves some rooms short while others are fine. We compare the air temperature and flow at the registers with what the equipment is producing; when the loss is in the ducts, duct repair is the fix, not a bigger system.
Carrier furnaces, heat pumps and ductless units
On furnaces, the questions are ignition, flame sensing, venting and the limit switches. On heat pumps, the defrost control, the reversing valve and any backup heat are added to the cooling checks; see heat pump services. Carrier ductless units get filter, coil and drain cleaning, a sensor check and a look at the flare joints where leaks begin.
Keeping the warranty useful
Carrier’s parts coverage depends on the model, the install date and whether the system was registered after installation. Keep your invoices and service records together; they help if a claim comes up. We install factory certified parts that carry the manufacturer’s warranty, and our own work carries a labor warranty. We are independent and not affiliated with Carrier, so what we recommend is based on the system in front of us.
Local notes
A Carrier AC in a Novato or San Anselmo home can sit idle through weeks of cool weather and then run hard through a hot spell, which is when weak capacitors and dirty coils show up. A yearly maintenance visit in spring catches most of them, and maintenance plans add priority scheduling and repair discounts.