The Setra Model 241 is an adjustable low differential pressure switch built to monitor air, non-combustible gases, and non-corrosive gases. It reads differential pressure, gauge pressure, or vacuum (negative pressure), and switches a contact once the reading crosses your set point – useful anywhere you need a simple go/no-go pressure signal rather than a continuous 4-20mA output.
We see this used a lot on HVAC systems, air handling units, and cleanrooms, as well as in building automation setups for air filter monitoring, ventilation and fan flow control, and general fluid or gas flow control. It’s also commonly used for equipment protection – overheat protection on heating coils, or frost protection on cooling circuits.
In actual application, the unit comes complete with an L-shaped metal mounting bracket, two plastic connecting pipes, a 2-metre PVC hose, and mounting screws, so there’s not much extra to source. One thing worth flagging: for best accuracy it should be mounted vertically. If you need to mount it horizontally with the cover facing up, the switching point shifts about 20 Pa higher than the marked scale, so that’s worth accounting for during commissioning.
Before we quote this, we would normally check which pressure range you need (20-200Pa, 40-400Pa, 200-1000Pa, or 500-2500Pa), the mounting orientation, and the electrical load on the switch contact. Hope this helps.
