The National Controls BOX-A1210-CHNF is a furnace control unit and flame safeguard device for monitoring a gas or oil-fired furnace. It includes a safety shut-off valve that will turn off the gas or oil supply in the event of a malfunction. It also features a low-temperature controller, high-limit switch, fan control, manual and automatic reset relays, and other various functions. Additionally, it is designed to control the flame actuation, lockout control, and blower motor with a single knob. This control can accommodate various burner systems, with difficulty levels ranging from easy to complicated.