AC Repair Rochester NY: When an air conditioner quits without warning, the cause is often simpler than it feels in the moment—power issues, thermostat settings, safety switches, or airflow problems can stop a system fast. If you’re in Rochester or the areas we serve around Rochester, a quick check can sometimes get you cooling again in minutes.
If the quick checks don’t help—or the system shuts off again—this guide will help you identify the likely cause and know when it’s time to call MGM Heating & Cooling for 24/7 emergency service.
Before You Start: Safety First
If you smell burning, hear loud buzzing/grinding, see smoke, or your breaker trips repeatedly, shut the system off and call for service. Some AC components can be dangerous to handle without proper tools, and repeated restarts can lead to bigger failures.
5-Minute Quick Checks (Safe DIY)
- Thermostat settings: Set to COOL, Fan to AUTO, and lower the setpoint 2–3 degrees below room temperature.
- Power: Check the breaker panel for AC/air handler and outdoor unit circuits.
- Airflow: Replace a dirty filter and make sure supply/return vents aren’t blocked.
- Water/drain: Look around the indoor unit for water near the drain pan.
- Outdoor unit: Confirm it has power and isn’t packed with debris.
If you need fast help, go straight to Cooling & AC service (installation, repair, maintenance, and air quality) here:Emergency? Call (585) 490-5084 — 24/7 response available.
1) Tripped Breaker or Outdoor Disconnect
A power surge, storm, or overloaded circuit can trip a breaker and make your AC appear completely dead. Many homes have separate circuits for the indoor equipment and the outdoor condenser, so one can trip while the other looks normal.
What you can do:
- Reset a tripped breaker once.
- If you know where your outdoor disconnect is and it’s safe to access, confirm it’s on.
Call a pro if: the breaker trips again quickly. Repeated trips usually mean an underlying electrical problem that should be diagnosed, not “forced” back on.
2) Thermostat Problems (Mode, Batteries, or Calibration)
Sometimes the system is fine—but the thermostat isn’t sending a cooling call. This can happen after a power outage, when batteries die, or when settings get changed.
What you can do:
- Confirm COOL mode and a lower setpoint.
- Replace thermostat batteries (if applicable).
- Make sure the thermostat display is stable and responsive.
Call a pro if: the thermostat is blank or the system won’t respond after confirming correct settings.
3) Clogged Condensate Drain (Safety Float Switch Shutoff)
Your AC pulls humidity from the air and drains that moisture away. When the drain line clogs, water can back up into the drain pan and trigger a float switch that shuts the system down to prevent water damage.
Clues this is the issue:
- The AC stopped suddenly (often on humid days).
- You notice water near the indoor unit or a damp area by the drain pan.
- The system may run briefly, then shut off again.
Best move: turn the system off and schedule service if there’s standing water, a recurring shutoff, or you can’t confirm the drain is clear.
4) Dirty Filter → Low Airflow → Frozen Coil
A dirty filter can reduce airflow so much that the evaporator coil becomes too cold and starts freezing. Once ice builds up, cooling performance drops and the system may stop or run without actually cooling.
What you can do:
- Replace the filter.
- Turn cooling OFF and let the system thaw (fan-only can help thaw faster).
Call a pro if: it freezes again. A repeat freeze-up often means deeper airflow issues or refrigerant-related problems.
5) Frozen Coil from Low Refrigerant (Possible Leak)
If refrigerant is low, the coil can freeze and the system may stop cooling or shut down. Refrigerant doesn’t “get used up,” so low refrigerant typically indicates a leak that should be found and fixed.
Signs:
- Ice on the copper line or indoor coil area.
- Weak cooling, then shutdown.
- Sometimes hissing near refrigerant lines.
What to do: shut off cooling and schedule a diagnostic. Avoid quick “top-offs” without leak detection.
6) Capacitor/Contactor or Other Start Components (Outdoor Unit Won’t Run)
If the indoor blower runs but the outdoor unit doesn’t, a common culprit is a failed start component. On hot days, these parts are under more stress and failures can feel sudden.
Symptoms:
- Clicking at the outdoor unit but no startup.
- Humming without the fan turning.
- Warm air indoors even though the thermostat is calling for cooling.
Important: don’t open the outdoor unit or try DIY electrical repairs. This is a job for a trained tech.
Want to see real installs we’ve completed in the Rochester area? View this Fujitsu mini-split + Amana central AC installation project.
7) Outdoor Unit Overheating (Dirty Coil, Blocked Airflow, Fan Issues)
When the outdoor coil is clogged with debris (cottonwood, grass clippings, leaves), the system can overheat and shut down for protection or run inefficiently.
What you can do:
- Clear debris around the unit and keep airflow space open.
- Don’t pressure-wash delicate fins unless you know what you’re doing.
Call a pro if: the outdoor fan isn’t running normally, the unit short-cycles (turns on/off frequently), or cooling is inconsistent.
When to Call MGM Heating & Cooling (Don’t Wait)
Call if:
- The breaker trips more than once.
- You see ice, water leaks, or repeated shutdowns.
- The outdoor unit won’t run, or you hear abnormal noises.
- The system runs but blows warm air.
If your AC suddenly stopped working, the cause is often a simple power, thermostat, drainage, or airflow issue—but repeated shutdowns and warm air can signal a bigger problem. When in doubt, turning the system off and getting a professional diagnosis can prevent more expensive damage.
Want to see real results from our team? Browse our HVAC project portfolio in Rochester and surrounding areas.
Need help now? Call MGM Heating & Cooling at (585) 490-5084 for 24/7 emergency AC repair in Greater Rochester or request service through our Cooling page.
