McDonnell & Miller 157S-R Controller R-22 Contractor Reliability: Simple 3-wire terminal

Contractor Reliability: Simple 3-wire terminal interface reduces field installation time and simplifies Series 14 troubleshooting

Once the pressure rises above the differential setting

Durable Construction: Engineered to withstand the rigors of industrial mechanical rooms and frequent cycling

This unit features a power-open/power-close mechanism driven by a 24V motor

McDonnell & Miller 157S-R Controller R-22 Contractor Reliability: Simple 3-wire terminalThe McDonnell & Miller 157S R (Part Number 176220) is a heavy duty, float operated combination low water cut off and pump controller designed specifically for steam boilers with an integral water column. This model serves as the upgraded direct replacement for the McDonnell & Miller 157 R, transitioning from older mercury switch technology to reliable, bimetal snap acting switches for enhanced safety and modern compliance. Built with a corrosion