When an air conditioner in Novato, San Rafael, San Anselmo, Larkspur or Sausalito stops cooling, the cause is usually on a short list: a clogged filter or another airflow problem, a failed capacitor or contactor, a dirty outdoor coil, a blocked condensate drain, or a refrigerant leak. From the living room they all look the same - warm air at the vents - and each needs a different fix. A proper AC repair visit measures before it replaces anything, so you do not pay for refrigerant when the real fault is a worn electrical part.
What we check, in order
- Thermostat and power. Is the thermostat actually calling for cooling, and does power reach both the indoor and the outdoor unit? A tripped breaker, a pulled disconnect or a loose thermostat wire stops the whole system.
- Airflow. A dirty filter, closed registers, a dusty evaporator coil or a slow blower starve the indoor coil of air. The system then looks low on refrigerant when it is not, so we measure the temperature drop across the coil before anyone connects gauges.
- Electrical parts under load. Run capacitors, contactors and fan motors fail far more often than compressors. We test them while the unit runs and check the amp draw of each motor.
- The outdoor coil. The condenser has to release the heat taken out of the house. Leaves, dust and spider webs pack the fins and the system falls behind on warm afternoons.
- Refrigerant. Only after the airflow and electrical checks do we read pressures and temperatures. A low charge means a leak somewhere, and topping it up without finding the leak only buys time. Our technicians are EPA-certified to handle refrigerant.
- Drain and safety switches. A clogged condensate line can trip a float switch and shut the system down, or leak into a ceiling or a closet.
Symptoms and what they usually mean
| What you notice | Likely cause | What it usually takes |
|---|---|---|
| Outdoor unit hums, fan does not spin | Failed run capacitor or seized fan motor | Capacitor or motor replacement |
| Air from the vents is only slightly cool | Dirty filter or coil, low charge | Cleaning, airflow fix or leak search |
| Ice on the copper line or indoor coil | Restricted airflow or low refrigerant | Thaw, then fix the airflow or the leak |
| Starts and stops every few minutes | Thermostat, overheating or electrical fault | Testing before any part is changed |
| Water around the indoor unit | Clogged condensate drain or cracked pan | Drain clearing and float switch check |
| New rattling, screeching or banging | Loose panel, worn motor bearing, compressor trouble | Inspection; switch off if the noise is loud |
| Breaker trips when the AC starts | Shorted motor, compressor or wiring | Electrical diagnosis |
Our problem guides go deeper on AC not cooling, AC blowing warm air, frozen AC coils, refrigerant leaks, short cycling and strange noises.
Why Marin air conditioners fail on the first hot day
Fog and bay breezes keep much of Marin cool, so a central AC may run only a few weeks a year. Inland - in Novato, San Anselmo and the north side of San Rafael - summer afternoons get noticeably hotter, and that is when a system that sat for months suddenly runs for hours. A capacitor that had been weakening, a drain line clogged with algae, or an outdoor coil buried under last fall’s leaves all show up at once.
Near the water the wear is different. In Sausalito and along the bay side of San Rafael and Larkspur, salt air corrodes outdoor coil fins and electrical terminals, so we look closely at the condenser and its connections. On hillside lots, outdoor units are often squeezed into narrow side yards or onto decks where air cannot move freely around the coil.
Safe checks before you call
- Set the thermostat to Cool, a few degrees below room temperature, and replace its batteries if it uses them.
- Pull the filter. If it is grey and matted, put in a new one.
- Open the supply registers and move furniture away from the return grille.
- Check the breakers for the furnace or air handler and for the outdoor unit.
- If you see ice, switch the system off and let it thaw for a few hours.
If a breaker trips again after you reset it, leave the system off and call. Repeated restarts can damage the compressor.
Pricing, parts and brands
You get an itemized price after the diagnosis, before any work begins, with no hidden fees. We explain what failed and recommend only the repairs you need. Repairs use factory certified parts; the parts keep the manufacturer’s warranty and our work carries a labor warranty. We work on all major brands, including Carrier, Trane, Lennox, Rheem, Goodman and Daikin.
Repair or replace?
One failed part on a system that otherwise cools well is almost always worth repairing. Replacement becomes a fair question when an older system needs a compressor or an indoor coil, when it still runs on R-22 refrigerant (no longer produced, so service gets harder every year), or when it has needed several repairs in a few seasons. If that is where you are, read about AC installation or a heat pump, which cools and heats with one system. A spring maintenance visit catches most of the problems above before the warm weather, and the town pages for Novato and San Rafael cover local details.