HVAC Repair Issues and Fixes
Your HVAC system is the heart of your home’s comfort. But like any major appliance, it’s bound to run into trouble from time to time. From poor airflow to strange smells and sounds, many common HVAC problems are easier to troubleshoot than you might think—especially if you have a helpful guide.
In this updated post, we’ll walk through the most frequent HVAC issues, how to troubleshoot them, and what steps you can take to prevent future breakdowns.
HVAC Maintenance & Repair Checklist: Common HVAC Issues & Solutions
1. Poor Airflow
Common HVAC issue: Weak airflow or no air coming from vents
Possible causes:
Clogged air filter
Leaky or obstructed ducts
Malfunctioning blower motor
Fix:
Replace the air filter every 1–3 months
Check vents for obstructions and furniture blockages
Schedule a duct inspection and airflow assessment
Poor airflow is one of the most common HVAC issues and often leads to reduced system efficiency and higher energy costs. It also affects indoor air quality.
2. HVAC System Not Heating or Cooling
Common HVAC dysfunction: No warm or cool air from system
Possible causes:
Thermostat settings or malfunction
Tripped breaker or power switch off
Furnace ignition or AC compressor issue
Fix:
Double-check the thermostat and replace batteries
Ensure power switch is on and breaker hasn’t tripped
If furnace or AC still won’t start, call for professional diagnostics
This is a frequently searched common HVAC problem, especially during seasonal transitions. With regular maintenance, this can easily be avoided.
3. Strange Noises
Common HVAC problem: Squealing, banging, humming, or rattling
Possible causes:
Loose parts
Dirty burners or motor bearings
Failing blower motor or fan blade
Fix:
Describe the sound and location to a technician
Turn the system off to prevent further damage
Schedule a service call to identify the source
4. Unusual Smells
Common issue: Burning, musty, or rotten egg odor from vents
Possible causes:
Dust or debris buildup
Mold growth in ducts
Electrical issue or overheating parts
Gas leak (in the case of rotten egg smell)
Fix:
Turn off the HVAC system immediately if you smell gas
Schedule a duct cleaning or mold inspection
Have an HVAC pro check wiring and electrical connections
5. Short Cycling
Problem: HVAC system turns on and off rapidly
Possible causes:
Clogged air filter
Incorrect thermostat placement
Oversized system
Fix:
Replace the air filter
Relocate the thermostat if it’s near heat sources
Have your system evaluated to ensure correct sizing
Short cycling reduces system lifespan and often indicates deeper HVAC problems that need professional attention. If not, your system needs to work harder.
6. HVAC System Won’t Turn On
Checklist to troubleshoot:
Check thermostat batteries and settings
Flip HVAC switch to ON
Reset circuit breaker
Make sure furnace or AC door is securely shut
If the system still won’t turn on, call Miller’s Heating & Air for expert troubleshooting.
7. Leaks or Moisture Around Unit
Common HVAC issue: Water pooling around furnace or indoor AC unit
Possible causes:
Blocked condensate drain
Cracked drain pan
Frozen evaporator coils
Fix:
Clear the drain line with vinegar or call a technician
Replace the drain pan if damaged
Have coils professionally inspected and defrosted
8. Ignition or Pilot Light Issues (Gas Furnace)
Gas furnace troubleshooting tip:
Symptoms:
Furnace won’t ignite
No heat
Possible causes:
Pilot light out
Cracked or dirty igniter
Gas supply or valve issue
Fix:
Relight the pilot (if applicable)
Call a professional for any ignition component issues
When it comes to how to fix a furnace, anything gas-related should always be handled by an expert.
Preventative HVAC Maintenance Tips
Regular HVAC maintenance prevents costly repairs and improves overall system performance. Seasonal tune-ups also help extend system lifespan.
HVAC maintenance checklist:
Replace filters every 1–3 months to help prevent clogged filters. You can check out our filter shop for replacements.
Schedule annual inspections
Keep vents and returns clean and unblocked
Clean outdoor AC units and remove debris
Seal ductwork leaks
Test carbon monoxide and smoke detectors
When to Call a Professional
Some HVAC issues are easy DIY fixes, but others can be dangerous or complex. Call a pro if you notice:
Repeated breaker trips
Burning smells or unusual sounds
Gas furnace ignition issues
Frozen coils or leaking refrigerant
For reliable HVAC repair in Vancouver or Portland, contact Miller’s Heating & Air.
Schedule a consultation with our team today and take the first step toward a more comfortable, energy-efficient future.
