How do I set up a backup heat source on my Honeywell T6 Pro thermostat?

Navigate to ISU settings, select 'Aux/E terminal control', change settings from Drive both Aux & E together (0) to independent setting (1). Ensure compatibility with model.

From the official Honeywell Home T6 Pro Th6320u2008 manual, page 9

Have a follow-up question?

Answers from the official manual.

Common questions