The first useful question about a Carrier system in Menlo Park, Atherton or Portola Valley is which line it belongs to. Carrier sells its air conditioners, heat pumps and furnaces in three lines, Comfort, Performance and Infinity, and the difference between them lies mostly in how the compressor and the blower run. That decides where a fault is likely to be and how it gets diagnosed.
What Carrier makes
Central air conditioners, heat pumps, gas furnaces, fan coils, ductless systems, packaged units, thermostats and indoor air quality equipment. Carrier also pairs heat pumps with gas furnaces in hybrid systems that switch between the two heat sources.
Which Carrier do you have?
| Line | How it usually runs | What we test first |
|---|---|---|
| Comfort | Single-stage: fully on or fully off | Capacitor, contactor, fan motor, filter and coil |
| Performance | Single-stage or two-stage | Staging signals and wiring, then the electrical parts |
| Infinity | Two-stage or variable-speed, with a communicating wall control | The control’s fault history, then sensors, drive and data wiring |
The model number on the outdoor unit’s data plate tells us the line and the version, so read it to us when you call.
Greenspeed: the top of the range
The top Infinity equipment uses Greenspeed Intelligence, Carrier’s name for a variable-speed compressor driven by an inverter. It runs at low speed for long stretches, pulls more moisture out of the air than a single-stage unit and avoids the hard starts that wear one out. An inverter-driven compressor also has no run capacitor, so the most common repair on Comfort equipment does not apply. When a Greenspeed system fails, the cause is more often a sensor, the drive electronics or a fault on the data wiring, and the wall control’s stored history usually points the way. Replacement boards and motors on these systems must be the right match and set up after fitting.
Older Carriers and refrigerant
Many homes here have had a Carrier for a long time. The data plate also lists the refrigerant, and that matters as much as the age:
- R-22, on older units, is no longer made or imported in the US, so every recharge draws on a shrinking supply.
- R-410A is what most current home systems use.
- Carrier’s newest equipment uses a newer, lower-impact refrigerant, so a new outdoor unit is normally installed with a matching indoor coil rather than connected to the old one.
Refrigerant is not used up. A system that needs more every season has a leak, and it should be found before anything is added. Indoor coils with copper tubing can develop pinhole leaks over the years, and the outdoor coil can be damaged by debris, a trimmer or a rub point.
Warranty and what to have ready
Carrier coverage depends on the line, the install date and whether the equipment was registered, and it covers parts, not the labor to fit them. When you call, have the model and serial numbers of the outdoor unit and the furnace or fan coil, the install date if you know it, and what the thermostat or furnace board is showing. Keep the installation invoice and registration confirmation with them. Our warranty page has the full list.
Repair or replace
On Comfort equipment, capacitors, contactors and fan motors are quick repairs. On an Infinity system, a sensor or a board is usually worth fixing while the system is young. A major leak or a failed compressor on an older R-22 Carrier is where replacement makes more sense. If you do replace, the lines differ in staging, noise and efficiency; we explain what each would change in your house and give you the options, parts and labor in writing.
Local notes
Summer highs in Menlo Park often sit in the low 80s, so two-stage and variable-speed equipment spends most days at low output while a single-stage Comfort unit cycles on and off more often. In Atherton’s larger homes, an Infinity system may run several zones with motorized dampers, and a room that never cools can be a stuck damper or a zone sensor rather than the equipment. Portola Valley’s hot afternoons push outdoor units hardest in late summer, which is when a tired capacitor on a Comfort unit tends to give up. A spring visit under an HVAC maintenance plan catches most of these early.