Amana-Goodman 2521302S Heat Exchanger 30067439-890 though the "B" port is

though the "B" port is the standard service port for normally closed operations

With a Type 3R rainproof rating

Technicians must install this unit a minimum of 6 inches above the highest downstream point of the water system to ensure the atmospheric vent functions correctly during a loss of supply pressure

making it a direct match for various Lennox residential and light commercial units

this is a direct cross-reference for Trion Air Bear 20x25 models

Amana-Goodman 2521302S Heat Exchanger 30067439-890 though the "B" port isThe Amana Goodman 2521302S Heat Exchanger is a critical OEM replacement part engineered to restore the heating efficiency and safety of your HVAC system. As a genuine 4 cell heat exchanger, this component is precision manufactured to facilitate optimal thermal transfer within Goodman and Amana gas furnaces. Designed for high performance durability, the 2521302S features robust construction that resists thermal fatigue and corrosive combustion