Assessing Coil Condition
The condition of a unit's coils is a primary indicator of its health, efficiency, and past maintenance. Every HVAC and refrigeration unit has two coil sections:
The Condenser Coil: This is the outdoor coil, typically visible without opening the unit. Its job is to release heat.
The Evaporator Coil: This is the indoor coil, located inside the unit and requiring a panel to be removed for inspection. Its job is to absorb heat.
Coil Inspection Checklist
The following points apply to both condenser and evaporator coils and are critical to a proper assessment.
What to Look For
- Cleanliness Look for dirt, leaves, or cottonwood buildup on condenser coils. On evaporator coils, check for a blanket of dust. A layer of grime acts as an insulator, reducing efficiency and forcing the unit to work harder.
- Fin Condition The delicate metal fins should be straight. Bent or crushed fins block airflow, which is just as damaging to efficiency as a dirty coil.
Common Problems & Red Flags
- Visible Damage Dents or holes from hail, rocks, or vandalism are immediate red flags, as they can cause costly refrigerant leaks.
- Corrosion Coils that are white, crusty, or flaky to the touch are severely corroded. This indicates the coil is nearing the end of its life and could fail at any moment, leading to a major repair or unit replacement.
Pro Tip: Indoor Air Quality
A dirty evaporator (indoor) coil is especially problematic. It not only hurts efficiency but can also lead to poor indoor air quality inside the building. This is a critical checkpoint.