it is best practice to verify if the 24V coil is pre-installed

as these cause ignition failure

use a manometer to verify the actual draft

Always inspect the burner area when replacing a damaged ignitor harness

Reznor 120153 Orifice 321042-401 it is best practice toThe Reznor 120153 Orifice is a precision engineered #20 burner orifice designed specifically for maintaining consistent gas flow and combustion efficiency in industrial heating systems. As an authentic Reznor replacement part, this 1 2" burner nozzle features a durable steel body with an NPT connection, ensuring a leak proof seal and long term reliability under high thermal stress. For contractors servicing Reznor unit heaters or duct furnaces,