USEFUL INFORMATION
BATTERY STATUS
The ST620 checks the battery voltage frequently during normal operation .If the battery
voltage is sensed as being low, the low battery indicator will be displayed on the screen.
Although the programmable thermostat will continue to operate normally at this stage, you
should replace the batteries as soon as possible to prevent the ST620 entering OFF mode.
OFF MODE
The Low Battery indicator will be displayed if battery voltage is detected as “low”, in
this case the thermostat functions normally during low battery except the backlight will be
turned off. The ST620 will enter into OFF mode if the battery voltage falls drastically low, and
all outputs will turn off.
As all functions except sampling the battery voltage are disabled in OFF mode, it is
recommended that you replace the ST620 batteries as soon as possible to restore normal
operation.
If the voltage of the replaced batteries is not high enough (if older batteries have been used)
the unit will remain in OFF mode and will not reset.
BACKLIGHT
The backlight of the ST620 is switched on automatically whenever the Touch Ring is activated, or any of the keys are
pressed. The backlight will remain illuminated for approximately 6 seconds after the last key press, except if you are
changing settings within the Clock, Programme or Temporary Override modes – in this case, the backlight will remain
illuminated for 10 seconds after the last key press.
The backlight will not illuminate if the ST620 battery is low, or if the Slide Switch is in the LOCKED position.
39ST620WBC INSTRUCTION MANUAL
