Honeywell Fema DWR Serie Montage- Und Bedienungsanleitung Seite 53

2. Pressure Monitors with Adjustable Switching Differential DWR...-203 / -303 (not for DGM)
In general:
Fig. 8. Wiring diagram
With rising pressure
3–1 opens, 3–2 closes
With falling pressure
3–2 opens, 3–1 closes
MU2B-0264GE51 R0220G 53