A boxed or cased evaporator coil is an indoor heat-exchanger assembly installed in a factory cabinet. It is commonly matched with a gas furnace and outdoor air conditioner or heat pump.

A boxed coil is a type of evaporator-coil assembly supplied in a cabinet. Depending on system operation, a heat-pump indoor coil can function as an evaporator during cooling and as a condenser during heating.

A cased coil is commonly installed with a compatible furnace in an approved upflow, downflow or horizontal configuration, depending on the specific coil and furnace application.

No. The indoor coil, outdoor unit, metering device and other components should be selected as an approved matched system according to manufacturer application data and current certification requirements.

Correct matching affects system capacity, efficiency, refrigerant performance and reliability. The exact indoor coil and outdoor equipment combination should be verified before installation.

The metering device controls refrigerant flow into the indoor coil. Depending on the equipment, it may be a thermostatic expansion valve, electronic expansion valve or another approved device.

A thermostatic expansion valve, or TXV, meters refrigerant into the evaporator coil based on operating conditions. The required metering device depends on the approved equipment combination.

Refrigerant compatibility depends on the exact model. Newer equipment may be designed for refrigerants such as R-32 or R-454B, while existing systems may use R-410A or other refrigerants. Always follow the equipment listing and manufacturer documentation.

Do not assume coils are interchangeable across refrigerants. The indoor coil, metering device and complete system must be listed and approved for the specific refrigerant and application.

Coil selection is based on the approved outdoor-unit match, furnace or air-handler application, system capacity, airflow, cabinet dimensions, refrigerant and manufacturer engineering data.

Yes. Proper airflow across the indoor coil is essential for capacity, temperature control, humidity removal and system operation. Duct restrictions or incorrect blower setup can reduce performance.

During cooling, moisture in the indoor air can condense on the cold coil. The condensate pan and drain system must manage that water correctly.

Potential causes include inadequate airflow, dirty filters or coils, blower problems, refrigerant-system issues, metering problems and other faults. A frozen coil should be professionally diagnosed.

Refrigerant leaks can result from corrosion, vibration, physical damage, manufacturing defects or other deterioration. The location and severity of a leak should be evaluated before deciding between repair and replacement.

Sometimes. The existing outdoor unit, refrigerant, furnace or air handler, metering device, system age and approved equipment match must be evaluated first.

Yes. Advanced Service Company LLC installs compatible indoor coils as part of qualifying HVAC replacements, furnace-and-AC systems, heat-pump systems and complete HVAC installations.

Yes. Advanced Service Company LLC diagnoses qualifying coil, refrigerant, airflow and condensate problems on central HVAC systems.

FREE estimates are available for qualifying new HVAC systems and system change-outs. Major evaporator-coil failures may also qualify for a second-opinion evaluation.

The best choice depends on system age, refrigerant, efficiency, warranty, outdoor-unit condition, furnace or air-handler condition, repair cost and equipment compatibility.

Advanced Service Company LLC serves North Alabama, including Somerville, Decatur, Huntsville, Athens, Madison, Hartselle, Priceville and surrounding communities.