McDonnell & Miller 63-M-HD Head Mechanism 30067439-890 it is technically best practice

it is technically best practice to install it in a position where gravity doesn't compete with the internal spring

this unit provides a stable 240V secondary output

Technicians often specify the 013U-8063 for its robust limit-stop functionality

For cooling (open on temperature drop)

or condenser fan failure

McDonnell & Miller 63-M-HD Head Mechanism 30067439-890 it is technically best practiceThe McDonnell & Miller 63 M HD Head Mechanism (Part Number 143200) is a heavy duty replacement head mechanism designed for the Series 63 Low Water Cut Off. Engineered for both hot water and steam boilers, this manual reset mechanical control ensures critical safety by interrupting the electrical circuit to the burner in 15 psi steam or 50 psi water applications. It features a robust float operated design and includes the No. 2 M switch, providing