Installer's Guide Upflow/Horizontal and Downflow/ Horizontal, Gas-Fired, Direct Vent, Variable Speed Inducer, Modulating, Condensing, Communicating Furnaces *UHM and *DHM Models (*First letter may be A or T)
Installer's Guide - Variable Speed, 2-Stage Upflow/Horizontal and Downflow/Horizontal, Gas-Fired Furnaces "Fan Assisted Combustion System" Models: *UD2-A9V/*DD2-A9V (* may be A or T).
Installer's Guide Variable Speed, 2-Stage Communicating or 24V Upflow/Horizontal and Downflow/Horizontal, Gas Fired Furnaces Models: *UD2-ACV, *DD2-ACV (* may be A or T)