OEM Lennox 2-Stage Heat Exchanger Assembly — 13X33

The genuine OEM Lennox 13X33 two-stage heat exchanger assembly (superseding 614580-25 and related to 612989-04) transfers combustion heat into your home's air supply while keeping flue gases sealed and separated. Designed for Lennox two-stage furnaces, it supports both low- and high-fire heating operation, restoring the efficiency and quiet, even comfort those systems are built to deliver.

Common failure symptoms: Look for cracks or corrosion on the exchanger, a flickering or distorted burner flame across either firing stage, soot deposits, unusual odors during heating, and repeated high-limit trips that lead to short cycling. Since a damaged exchanger can leak carbon monoxide into the airstream, any of these symptoms calls for immediate replacement.

Why OEM matters: Two-stage heat exchangers are precisely engineered to handle variable firing rates, so an exact-match part is essential for both performance and safety. The authentic Lennox 13X33 assembly matches the original alloy, gauge, and geometry to seal correctly, stage heat properly, and maintain your warranty coverage. Aftermarket substitutes can disrupt staging and compromise safety. Choose OEM Lennox for accurate fit and dependable multi-stage heating.