McDonnell & Miller 51HD Head AssemblyThe McDonnell & Miller 51HD head assembly is engineered for reliable boiler performance. This head assembly (model 134900) serves as a dependable replacement part for compatible heating system controls. Designed to fit standard McDonnell & Miller boiler control configurations, the 51HD delivers precise operation, steady fuel and water management, and durable service life. Use this part to maintain efficiency, reduce downtime, and extend the life of

secure mounting in various assemblies

Rugged durability to withstand demanding environments and long service life

Honeywell RP471A1002 Pneumatic Relay delivers precise snap-action control for electronic and pneumatic systems

Media: Steam and water

Power Rating: 10 VA

and performance of your HVAC system

ensuring dependable operation in demanding environments

Built for lasting durability

Easy installation: Standard wiring connections for quick setup

Serves as a reliable interconnect cable for data

Use this part to ensure optimal ignition performance

Power rating: 300 W per bracket delivers robust