Unplug the oven power cord. Turn off the gas supply. Wait at least 30 minutes for any built-up gas to dissipate before working on the oven.
Open the oven door. Slide the oven racks out and set them aside.
Remove the screws at the back of the oven floor. Lift the oven floor out through the front of the XL44.
Remove the screw holding the oven igniter to the gas assembly in the right rear corner of the oven. Unplug the electrical harness leading from the igniter.
Position the new igniter onto the gas harness. Plug the electrical connector into its socket. Install the screw that holds the igniter in place.
Replace the oven floor. Install the two screws at the back to hold it in place.