McDonnell & Miller 51-2-HD Control Freon Always verify your capacitor rating

Always verify your capacitor rating matches the manufacturer's specification for this motor

For systems exceeding these pressure requirements

Key Benefits Modular Design: The PopTop actuator snaps directly onto the brass valve body

the internal snap disc has failed and the replacement limit switch is required

McDonnell & Miller 51-2-HD Control Freon Always verify your capacitor ratingThe McDonnell & Miller 51 2 HD is a heavy duty head mechanism only (Part Number 135100) designed specifically for field replacement on Series 51 2 mechanical water feeders. This unit is engineered for low pressure steam and hot water boiler applications, supporting systems with a maximum vessel pressure of 35 PSI. As a specialized low water cut off (LWCO) component, it features a snap acting SPDT switch that provides simultaneous feed control and