Lennox 12J31 – 613139-08A Indoor Coil is an OEM evaporator coil designed for reliable heat transfer and long-term performance in compatible Lennox HVAC systems. This indoor coil features a precision-engineered copper tube and aluminum fin construction, optimized for efficient refrigerant flow and consistent thermal exchange. With a compact 24 x 40.5 inch profile and high fin density, it is well-suited for residential and light commercial applications where space efficiency and performance are critical.

Manufactured by Lennox, this coil meets original factory specifications and is intended as a direct replacement, ensuring proper fit, airflow characteristics, and system efficiency when installed according to manufacturer guidelines.

 

Overview:

This indoor coil is built to support stable cooling performance and proper moisture removal from conditioned air. The 3/8 inch tubing and 3R15 FPI fin design help balance airflow resistance with heat transfer efficiency, contributing to dependable system operation across varying load conditions.

 

Key features:

OEM Lennox indoor evaporator coil
Part number 613139-08A (Lennox catalog 12J31)
Copper tube and aluminum fin construction
24 x 40.5 inch coil dimensions
3/8 inch tubing
3R15 FPI fin configuration
Designed for proper fit and airflow in compatible Lennox systems

 

Typical applications:

Residential split systems
Light commercial HVAC systems
Replacement of damaged or leaking indoor coils in approved Lennox equipment

 

Important notes:

This is a factory OEM component
Compatibility should be verified by model and serial number before ordering
Professional installation is recommended to ensure correct refrigerant charging and system performance