ensuring that the system shuts down quickly if the C554A cadmium sulfide flame detector fails to sense a flame

If your multimeter reads below 1

As a genuine OEM York furnace part

Do I need to disassemble the SA-19S before brazing it into the line

Johnson Controls KIT14A-613 Flange Kit Els PW 29614 ensuring that the system shutsInstall the Johnson Controls KIT14A 613 Flange Kit to ensure a high pressure, leak free connection for your 2" water valves. This companion flange kit is engineered for heavy duty commercial applications, specifically designed for use with Johnson Controls V43, V46, and V47 series pressure actuated water regulating valves. As a veteran grade OEM valve repair kit, it includes two rugged cast iron flanges with standard NPT (National Pipe Thread)