Every time I turn on my Sentry Xpress prior to programming, I get an E-1 in the display. This

E1 is the software version of your Sentry Xpress 4.0 controller. It is not an error code. Earlier versions of the controller did not show the software version on start up. Controllers that show this on start up have Add Hold Time, Change Target Temperature, Alarm, and Thermocouple Offset. These features are new with the 4.0 version.