The short answer
The symptom usually points to the cause: buzzing often means a failed capacitor, warm air can mean a frozen coil or refrigerant leak, and water indoors usually means a clogged drain. We confirm the cause with testing, explain it and repair it once you approve.
Air conditioning trouble in Menlo Park usually announces itself in one of a few ways: a strange noise, warm air from the registers, water where it should not be, or a system that refuses to start. Each symptom narrows the list of likely causes, and understanding that list helps you decide how urgent the problem is and what to tell a technician. ExpertFlow HVAC Repair Service sends technicians about nine miles north from Los Altos to repair cooling systems across the 94025 area, from add-on central systems in older homes to heat pumps and ductless units in newer construction. Rather than a generic overview, this page is organized by symptom, so you can match what you are seeing at home with the likely cause and the kind of repair it usually involves.
Noises and what they usually mean
Sounds from an air conditioner are often the first sign of trouble, and different sounds point in different directions. A loud hum or buzz from the outdoor unit with the fan sitting still often indicates a failed capacitor or a seized fan motor. Rapid clicking at startup can be a failing contactor or a control problem. Rattling suggests loose panels, debris inside the unit or a fan blade that has worked loose.
A high-pitched squeal or screech from the indoor blower or outdoor fan is often a bearing that is wearing out. Hissing near the refrigerant lines can indicate a leak. Any grinding or banging from the compressor itself warrants turning the system off until it is checked, because running it can cause further damage.
Warm air from the vents
When the blower runs but the air is not cool, the problem is usually in the refrigerant circuit or the outdoor unit. Check first whether the outdoor fan and compressor are running. If they are not, the cause is often electrical: a tripped breaker, a failed capacitor or contactor, or a thermostat that is not sending the cooling signal.
If the outdoor unit is running but the air is still warm, look for ice on the copper line near the outdoor unit or on the indoor coil. Ice typically means restricted airflow from a dirty filter or coil, or low refrigerant caused by a leak. Turn the system to fan only or off to let the ice melt, then call for service.
Water, smells and short cycling
A few other symptoms come up regularly in local homes, and each has a familiar set of causes.
- Water around the furnace or air handler: a clogged condensate drain, a cracked drain pan or a failed condensate pump.
- A musty smell when cooling starts: moisture and biological growth on the coil or in the drain pan.
- A burning or electrical smell: overheating wiring or motor, which calls for shutting the system off right away.
- Short cycling, where the system starts and stops every few minutes: an oversized unit, a thermostat in a poor location, low refrigerant or a safety switch tripping.
- High electric bills with weak cooling: a dirty outdoor coil, failing components or ducts leaking into the attic or crawlspace.
How we diagnose and repair
We confirm the cause rather than relying on symptoms alone. That means measuring voltage and current draw, testing capacitors and contactors, reading refrigerant pressures and temperatures, checking airflow and inspecting the drain system. In older Menlo Park homes we also look at the ducts, since leaks into an attic or crawlspace can make a healthy system seem weak.
Once we know the cause, we explain it in plain terms and describe the repair. Work begins only after you approve it. If a refrigerant leak is involved, we locate and repair it rather than simply adding refrigerant, because a recharge alone does not last.
When repair stops making sense
Repair is the right answer most of the time. It may not be when an older system needs a compressor, has a major coil leak, or still runs on R-22 refrigerant, which is no longer produced. In those cases we lay out the cost of repair against the option of replacing, and if your furnace is aging too, we can explain how a heat pump would cover both cooling and heating. Air District rules do not require replacing working equipment, so you decide on your own timeline.
We repair air conditioners in East Palo Alto, Atherton, Palo Alto, Mountain View and Los Altos Hills as well as Menlo Park.
More services in Menlo Park
- Heating Repair in Menlo Park
- Heat Pump Installation in Menlo Park
- AC Installation in Menlo Park
- Furnace Repair in Menlo Park
