McDonnell & Miller 157S-R Controller R-22 This switch is typically used

This switch is typically used as a pneumatic-electric interface to energize electric heat coils or fan motors in VAV boxes when a specific pneumatic branch pressure is reached

calibrated gate that reacts to minute changes in pressure

ensuring the airtight seal necessary to maintain precise inches of water column (WC) for the draft inducer

tailored for specific vertical coil configurations

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

McDonnell & Miller 157S-R Controller R-22 This switch is typically usedThe 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