How to Troubleshoot Common AC Issues Before Calling a Pro

Simple checks you can do before scheduling a service call

When your air conditioner starts acting up — weak airflow, strange sounds, warm air coming from the vents — it’s easy to panic. But not every AC issue requires a technician right away.

Sometimes, a few quick checks can save you time, money, and stress.

Here are the most common AC problems homeowners can safely troubleshoot on their own before calling in the pros at Sea Coast Air Conditioning.

1. Poor Airflow

Weak or reduced airflow is one of the most common complaints. Before assuming the worst, check these simple things:

✔ Check Your Air Filter

A clogged filter restricts airflow and forces your system to work harder.
If it’s dirty, replace it — this solves the problem in most cases.

✔ Make Sure Vents Are Open & Unobstructed

Walk through the home and confirm that no vents are closed or blocked by furniture, drapes, or rugs.

✔ Inspect the Outdoor Unit

If the condenser is covered in leaves, grass, or debris, airflow to the system drops.
Carefully clear away any buildup on or around the unit.

2. Warm Air Blowing From the Vents

This issue often has a simple explanation.

✔ Check the Thermostat Settings

Make sure the system is set to Cool and the fan is set to Auto, not On.

✔ Look for a Tripped Breaker

Your indoor or outdoor unit may have lost power.
Reset the breaker if needed — but don’t reset it repeatedly. If it keeps tripping, stop and call a professional.

✔ Inspect the Outdoor Unit

If the fan isn’t spinning or the unit isn’t running at all, it may be a capacitor or electrical issue that needs a technician.

3. Strange Noises

Hissing, clanking, grinding, or rattling sounds are your AC’s way of calling for help — but some noises can come from minor issues.

✔ Rattling or Vibrating

This may be something as simple as a loose panel or debris stuck in the fan.
Check for loose screws on the exterior panels and tighten if necessary.

✔ Buzzing Sounds

Often caused by debris, a dirty condenser coil, or a failing fan motor.
You can safely remove debris, but if the noise persists, call a pro.

✔ Grinding or Screeching

Turn the system off immediately — these noises usually indicate a mechanical problem like a worn-out belt or motor.

4. Water Leaking Around Your AC

Not all leaks mean disaster.

✔ Check the Drain Line

A clogged drain line is the #1 cause of indoor water leaks.
You can try clearing it using a shop vac on the outside drain line.

✔ Inspect the Filter Again

A clogged filter can cause the coil to freeze and thaw, creating leaks.

If leaks continue, turn the system off and call a technician — running a leaking AC can cause major damage.

5. AC Won’t Turn On at All

Before assuming the unit is dead:

✔ Verify the Thermostat Has Power

If it’s battery-operated, replace the batteries.
If it’s wired, make sure the screen isn’t blank or frozen.

✔ Check All Breakers

There may be a separate disconnect for the outdoor unit.

✔ Inspect the Safety Switch

If your system has a float switch, a full drain pan will shut the AC off to prevent water damage.
Clearing the drain may fix the issue.

When to Stop Troubleshooting and Call a Professional

While homeowner troubleshooting is helpful, there are times when it’s best to step aside and let a licensed technician handle it, especially if you notice:

• Burning smells
• Ice forming on refrigerant lines
• Constant breaker tripping
• Warm air after all basic checks
• Loud grinding or screeching noises
• Weak airflow that doesn’t improve

These issues usually require specialized tools and training and can worsen if ignored.

Need Help? Sea Coast Air Conditioning Is Here for You.

If your system still isn’t running right after these simple checks, our expert team is ready to help.