TC3XX Thermostat Operation After Power off / loss

TC3XX Thermostat Operation After Power off / loss


TC3XX thermostat is off when power is restored after a power loss

Product Line

Field Devices


  • TC300
  • TC303
  • TC353


The default operation mode when the TC3xx thermostat is powered up is in OFF mode.


An internal system setting (parameter 03) allows the possibility to alter the behaviour of the thermostat upon power restoration.

  • 00 = Restores with previous status 
  • 01 = Restores with power off.  (this is the factory default setting)
  • 02 = Restores with power on.
  • Once power is restored, the thermostat will remember all parameters (** with the exception of the TC303-3A2DPMS and TC303-3AADPMS) that were in place before the power failure.

The following specification numbers allow the thermostat’s restored state to be configured: -

TC303-3A2L TC303-3A4L TC303-3A2DLS * TC353-3A2DLS
TC303-3A4 * TC353-3A2L TC303-3A2DLMS * TC353-3A4DLS
TC303-3A2LM * TC353-3A4L TC303-3A4DLMS ** TC303-3A2DPMS
      ** TC303-3A4DPMS

For guidance and instruction on how to perform the adjustment of internal system parameters, please contact your local/regional support team.

* The TC353-3A2L, TC353-3A4L, TC353-3A2DLS and TC353-3A4DLS have been discontinued. Refer to PA-00686 - Product ObsolescenceNoticefor EMEA and APAC for further details.

** The TC303-3A2DPMS and TC303-3A4DPMS temperature set point will revert back to the default value after power is restored. This is as per designed.

Please note: internal system parameters MUST ONLY be changed by a trained Schneider Electric or an approved Partner technician.Incorrect setting of such internal system parameters may result in either undesired operation of the thermostat or irreversible damage.

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