The Trane XE90 is a high-efficiency furnace that reduces fuel waste by using up to 90 percent of stored fuel, and may require a thermostat restart to fix heating issues that occur while in use. A restart is the first step in attempting to resolve common furnace issues, and can fix minor problems that prevent the furnace from operating normally. Persistent problems with the Trane XE90 require professional repair, and is available depending on the validity of your appliance's warranty.
Slide the furnace's thermostat to the OFF position to disable the furnace. The thermostat is usually on an interior wall of the home. Wait for the furnace to stop running before continuing, as turning off an active furnace may take a few minutes for all parts to come to a complete halt.
Locate the furnace in your home's basement or utility room, and carefully pull off the furnace's door cover to access the blower.
Flip the manual reset switch to the down position near the blower motor on the right side of the furnace to restart it. Place the door cover back onto the furnace.
Slide the thermostat's switch to "HEAT" to restart the furnace. Once activated, the furnace automatically switches on and begins to heat your home.