"Paired" means the Pacbrake Wireless System and mobile device have detected each other, where "connected" means the Pacbrake Wireless System and the mobile device and synchronized, ready to communicate.
Approximately 10 meters (30 feet), unobstructed direct line-of-sight.
Your phone's Bluetooth must be turned "on", Wireless Controls need to be powered (vehicle ignition power "on"), and both devices need a reasonably unobstructed path in order to pair/connect.
If issues are experienced consult your phone's manual to ensure Bluetooth is enabled, check that the Wireless Controls ground and power connections are secure and that the Wireless Controller has some clearance between its surroundings. (Metal objects fully shrouding the Wireless Controls plastic enclosure can interfere with communication).
Due to changes in air temperature and atmospheric pressure, gauge pressure readings will vary. In cases of large variation, the system can be recalibrated by continuously holding drain button for 60 seconds.