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HVAC Troubleshooting Guide

Diagnose common heating and cooling problems

Try These First (Most Common Fixes)

✓ Check Your Thermostat

  • • Is it set to HEAT or COOL mode?
  • • Is the temperature set higher than room temperature?
  • • Are the batteries dead? Replace them.
  • • Is it plugged in and switched on?
  • • Try adjusting the temperature 3-5 degrees higher/lower

✓ Check Your Breaker Box

  • • Look for tripped breakers (handle in middle position)
  • • Flip the breaker OFF, then back ON
  • • Check your HVAC system breaker specifically
  • • If it trips again, there's an electrical issue—call us
  • • Don't ignore repeated breaker trips

✓ Replace Your Air Filter

  • • A dirty filter restricts airflow
  • • Check your filter monthly during heavy use
  • • Filters are usually near your furnace or returns
  • • Size is printed on the filter (typically 16x25x1 or 20x25x1)
  • • Replacement cost: $15-30

✓ Check for Blocked Vents

  • • Make sure furniture isn't blocking return/supply vents
  • • Check that dampers aren't closed in ductwork
  • • Vacuum around floor/wall vents to remove dust
  • • Ensure outdoor AC unit isn't blocked by plants/debris
  • • Poor airflow prevents proper heating/cooling

Common HVAC Problems & Solutions

AC Not Cooling

Common

Likely Causes:

  • • Dirty air filter reducing airflow
  • • Low refrigerant levels (leak)
  • • Frozen evaporator coils
  • • Faulty compressor or capacitor

What to Do:

Replace filter first. If still not cooling after 30 minutes, call us. Don't run the system continuously—it can cause more damage.

Furnace Won't Start

Common

Likely Causes:

  • • Thermostat not set to HEAT or batteries dead
  • • Tripped breaker or blown fuse
  • • Pilot light out (in older furnaces)
  • • Gas valve shut off
  • • Ignitor failed

What to Do:

Check thermostat, breaker, and gas valve. If you smell gas, leave the house and call us immediately. Don't attempt to relight the pilot yourself.

Strange Noises from System

Attention Needed

Types of Noises & What They Mean:

  • • Rattling: Loose parts or ductwork
  • • Squealing: Belt slipping or bearing issues
  • • Grinding: Compressor or motor problem
  • • Banging: Refrigerant backflow (serious)
  • • Humming: Usually normal, but loud = problem

What to Do:

Note what type of noise and when it occurs. Call us for diagnosis. Strange noises indicate problems that worsen over time.

Weak Airflow from Vents

Common

Likely Causes:

  • • Dirty air filter (most common)
  • • Clogged return vents or ducts
  • • Ductwork not sealed (leaking)
  • • Blower fan failing
  • • Dampers partially closed

What to Do:

Replace filter first—this fixes 80% of weak airflow issues. Check all vents are open and unblocked. If still weak, call for inspection.

High Energy Bills

Attention Needed

Likely Causes:

  • • Old, inefficient system
  • • Poor insulation or air leaks
  • • Dirty filters or coils
  • • Faulty thermostat
  • • System running constantly

What to Do:

Schedule maintenance tune-up. We'll identify efficiency problems. Upgrading to a high-efficiency system can save 10-40% annually.

Water Leaking from Unit

Urgent

Likely Causes:

  • • Clogged drain line (AC)
  • • Refrigerant leak
  • • Frozen evaporator coil
  • • Cracked condensate pan

What to Do:

Turn off AC immediately. Water damage can occur. Place towels under unit. Call us for same-day service. Don't wait—water damage gets expensive fast.

System Cycling On/Off Frequently

Attention Needed

Likely Causes:

  • • Undersized system for home
  • • Dirty filter restricting airflow
  • • Faulty thermostat
  • • Refrigerant leak (slow)
  • • Compressor issue

What to Do:

Check and replace filter first. Short cycling reduces system lifespan and efficiency. Schedule maintenance to diagnose root cause.

When to Call a Professional

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Safety Issues

Burning smell, gas smell, carbon monoxide alarm triggered—leave home and call immediately

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Complete System Failure

No heat/cooling, breaker keeps tripping, refrigerant leak visible

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Water Damage Risk

Water pooling under unit or leaking from indoors—can cause expensive damage

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After DIY Attempts Fail

You've tried basic fixes (filter, breaker, thermostat) and problem persists

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Annual Maintenance

Schedule spring and fall tune-ups to prevent problems before they start

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System Over 15 Years Old

Get a professional evaluation—replacement may be more economical than repairs

Still Having Problems?

Our expert technicians can diagnose and fix any HVAC issue. Available 24/7 for emergencies.

Call Now: 503-770-4822 Emergency Service