ST621TX INSTRUCTION MANUAL
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CONTROL MENU
By selecting the Control menu, the
installer can change the control
method used by the programmable
thermostat - either ON/OFF or Pulse
Width Modulation (PWM). The default
setting is ON / OFF.
On entering the menu, scroll to select the preferred option (ON/OFF or PWM control), and confirm
the choice using the OK button. Use the Arrow key to return to the Menu Option display.
PWM mode
should only be selected by the Engineer carrying out the installation or other qualified person.
RADIO CONTROLLED CLOCK
The ST621TX time and day of the week settings are updated automatically every day (at 12:00 AM or
2:00 AM) by the use of a very accurate internal Radio Controlled Clock.
The RCC status indicator will be displayed for 10 minutes during clock
updates. The indicator will flash during the time update process, after which
the indicator will be displayed for 5 minutes before turning off.
The time and date will also be automatically updated when the ST621TX is
powered up, or after the Reset Button is pressed.
If for any reason the ST621TX fails to automatically update the time
setting, then the data stored in the internal memory will be used. The clock
settings can also be changed manually if required – manual settings will be
overwritten at the next successful automatic update.