This 100 cubic inch block is a single unit

The heavy-duty construction of these tools ensures they withstand high-torque applications in residential and industrial heating environments

While the standard 200RB5T3 is uni-directional

and LGB boiler series (sizes 85-125)

McDonnell & Miller 351800 Hook-Up 30067439-890 This 100 cubic inch blockThe McDonnell & Miller 351800 Hook Up (Model SA259 24) is a critical upper quick hook up fitting designed for seamless integration with Series 47 and Series 47 2 mechanical water feeders. This professional grade component also serves as a direct replacement part for Series 42S A, 42A, and 64 A low water cut offs (LWCO). By utilizing this specific boiler control fitting, technicians can ensure precise water level monitoring without the intensive labor