The Lennox 16U03 – 619598-03 Cold End Header Box Kit is a genuine OEM replacement component designed to restore proper combustion airflow and condensate management in compatible Lennox gas furnaces. Installed at the cold end of the heat exchanger, this header box (collector box) plays a critical role in directing flue gases and collecting condensate generated during high-efficiency furnace operation.

Manufactured to original Lennox specifications, this cold end header box kit ensures a precise fit, dependable sealing, and long-term durability under normal residential heating conditions. Replacing a cracked, leaking, or deteriorated header box helps prevent pressure switch faults, condensate leaks, and reduced furnace efficiency. This OEM kit is engineered to match factory performance standards, making it the correct choice for professional HVAC repairs and maintenance.

Using genuine Lennox replacement parts helps maintain system reliability, supports proper furnace operation, and ensures compatibility with the original heat exchanger and inducer assembly.

 

Product Overview:

The Lennox 16U03 Cold End Header Box Kit is designed to collect and route combustion byproducts and condensate from the heat exchanger in high-efficiency Lennox furnaces. It restores proper airflow balance and condensate drainage, helping the furnace operate safely and efficiently. This kit is intended as a direct replacement for the original factory-installed header box.

 

Specifications:

Manufacturer: Lennox
Part Number: 619598-03
Catalog Number: 16U03
Product Type: Cold End Header Box / Collector Box Kit
Application: Gas furnace combustion air and condensate management
OEM Status: Genuine Lennox factory replacement part

 

Additional Notes: 

• Designed for direct-fit replacement on compatible Lennox furnace models
• Supports proper pressure switch operation and condensate drainage
• Professional installation is recommended
• Always verify furnace model and serial number compatibility before ordering