The word REMINDER indicates there is an excessive air leak somewhere. If you have not put your mask on, put the mask on your face and start breathing. If it is happening while you have your mask on your face, please disconnect all parts to the Z1/Z2 including your mask and tubing (battery from the PowerShell, PowerShell from the machine, and unplug it from the wall). Reassemble the parts to the Z1/Z2.

REMINDER will only appear on the Z2 if you have turned off the Auto Start/Stop function. Otherwise the Z2 will stop when your mask is removed.