I saved these instructions from another post. With apologies to the original poster of this info who deserves the credit for this:
How to bypass the BCV thermostat
TO CHANGE AC THERMOSTAT SETTINGS THE THERMOSTAT HAS TO BE PUT INTO "SERVICE MODE" IT IS SIMPLE TO DO BY PRESSING THE FOLLOWING KEYS ON THE FRONT OF THE THERMOSTAT.
EXECUTE THE FOLLOWING SEQUENCE:
1. PRESS (AND KEEP PRESSED) THE F/C KEY
2. PRESS (AND RELEASE) THE OFF/AUTO KEY
3. PRESS (AND RELEASE) THE DISPLAY KEY.
4. RELEASE THE F/C KEY.
UPON SUCCESSFULLY COMPLETING THIS SEQUENCE, THE LCD WILL DISPLAY PAR (PARAMETER) AND THE PARAMETER NUMBER.
1. PRESS THE UP ARROW KEY AND SCROLL UNTIL # 6 APPEARS. (NEW MODELS # 24)
2. PRESS THE OFF/AUTO KEY
3. THE CURRENT LOW TEMPERATURE IS DISPLAYED.
4. PRESS THE DOWN ARROW KEY AND SCROLL UNTIL THE DESIRED ROOM
TEMPERATURE APPEARS
5. PRESS THE F/C KEY