OFF MODE
The low battery indicator will be displayed if battery voltage is detected as
"low", in this case, the thermostat functions normally during battery low except
the backlight is 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 replaced batteries voltage is not high enough (treat as older batteries),
maybe the unit is still in OFF mode and can't 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.
21ST620 INSTRUCTION MANUAL
SLIDE SWITCH
The Slide Switch has two positions: UNLOCKED and LOCKED.
In the LOCKED position, the Touch Lock indicator will be visible on the LCD, and it will not be
possible to change the ST620 settings. If you are unable to change any thermostat settings, check that
the Slide Switch is in the UNLOCKED position.
RESET BUTTON
The Reset Button is provided as a way to restore the thermostat to its default factory settings. Pressing
this button will delete any previously entered settings.
ENERGY TIP
One way to set and use your room thermostat is to find the lowest temperature setting that you are
comfortable with, and then leave it set at this temperature. You can do this by setting the room
thermostat to a low temperature, (for example 17 °C) and then increasing the setting by one degree
each day until you are comfortable with the room temperature - you won’t have to adjust the
thermostat further, as adjustment above this setting will waste energy - a 1 °C increase in temperature
is equal to 3% of your heating costs.
