The most common cause of this problem is overpressure.
Overpressure happens because the diaphragm in the room pressure monitors is very thin since it is made to sense small changes in the low-pressure range. Therefore, it is not recommended to blow or suck on a port in any way. When installing tubes for pressure monitors, make sure that inlets are away from exhausts, ducts, fans, doors, air conditioning units, etc.
For the room monitor and pressure range you have selected you will want to check what the proof pressure is for that model. If the pressure seems stuck at one pressure you will want to try to zero, the monitor.
If the room pressure monitor is stuck at some pressure that is outside of a specified range, and you cannot restore the factory settings and you have tried to zero the instrument without success, then you can send the unit in for repair.
Here is the link for the RMA request form: https://www.setra.com/support/service