ENV-VST-C ViewStat Thermostat (Enhanced UI) Firmware v3.01/3.04

Last Updated: Sep 28, 2018


Prerequisites: Firmware v3.01/v3.04 or greater

Upgrade Instructions: Via NetLinx studio, perform an Axcess device firmware transfer for 2 tsk files.


  1. Perform a device query to verify that the device is online.
  2. Select loader.tsk and then the device number. Send the file. The thermostat will not reboot.
  3. Repeat step 2, sending wapp.tsk to the thermostat. Perform a hard boot to the thermostat when the transfer is complete. The thermostat will show the new revision in the online tree.


Firmware Revision History


  • All Celsius temperature displays (whether readings or setpoints) are in whole-degrees only
  • Temperature set point adjustment stops whenever a minimum or maximum is reached
  • When the thermostat has an out-of-range value, the thermostat will display the currently measured value
  • Filter change reminder counts down in calendar days. For example, if the user sets the filter change reminder for 90 days, once 90 days have passed since it was set, the filter change reminder will come on.
  • Thermostat is able to humidify any time the system is not cooling, The thermostat will not humidify if dehumidification is operating.
  • The thermostat should be able to dehumidify at any time, and not dehumidify if humidification is operating
  • Thermostat uses the current day's weather to determine and display the current weather on the main and current conditions screens
  • WAKE command will cause the backlight brightness to change to its active setting AND display the main screen
  • Comfort recovery will function in Auto, Heat, or Cool mode. The comfort recovery message will show if current weather is disabled.
  • Default fan speed is set to "Low" (corresponding to G1), and the default fan button lock-out will be "Yes"
  • When button lock-out is active on Mode and Fan Speed, the setting text will indicate that this is a locked-out setting
  • Diagnostic mode to assist with installation and debugging
  • Improved dual-stage heat pump operation (heating mode)
  • The thermostat now provides channel feedback codes for each on-board relay
  • A new weather condition added to the FK command: DUST
  • Change operating mode from main screen to select Mode, Fan, or Program
  • Page-Specific Help Screens


Programming Information


  • Command: FILTER <DAYS>
  • Response: None
  • Command: ?FILTER
  • Response: FILTER <DAYS>
  • Where:
  • DAYS: number of days until the filter change reminder activates. Range is 0 to 180.
  • Note: When the FILTER command is sent to the thermostat with <DAYS> greater than zero, the filter change reminder will be automatically turned off (implying that channel 160 will also be OFF). If the FILTER command is sent to the thermostat with <DAYS> set to zero, the filter change reminder will immediately come on showing the icon on the screen and setting channel 160 to ON.



  • Command: MESSAGE <DISP | CLEAR> [<TEXT>]
  • Response: None
  • Where:
  • DISP : indicates that a message should be displayed with TEXT
  • CLEAR : indicates that the message should be cleared from the screen and operation returns to normal
  • TEXT : a string with the contents of the message
  • Note: When the user clears the message screen using the Mode/Select button, the thermostat will send SEND_COMMAND 'MESSAGE CLEAR' so that the master knows the message was cleared by the user.
  • Examples:
  • SEND_COMMAND 'MESSAGE DISP "Welcome to the Plaza Hotel"'
  • If the backlight is inactive when the message is sent, it should appear turning on the display and showing the message. The backlight shall remain on for the duration of the traditional backlight timing settings and then dim. The message shall remain until the user presses a navigation button to remove the message.



  • Command: ?PG D<DAY> SP<DaySP>
  • Response: PG D<DAY> SP<DaySP> HT<HeatSP> C<CoolSP> HM<HSP> DM<DSP> T<TIME>
  • Command: PG D<DAY> SP<DaySP> HT<HeatSP> C<CoolSP> HM<HSP> DM<DSP> [T<TIME>]
  • Response: None
  • <TIME> will be the hour and minutes using a 24-hour clock, with no colon in between the hours and minutes (e.g. 0900 or 2315). It is left as an option on the PG command (not optional on the PG response), in order to support backwards compatibility. If T<TIME> is not provided, the thermostat will leave the time setting for that day and setpoint at its currently set value.



  • Command: FK <KY1> <KY2> <KY3> <KY4> <KY5> [<KYC>]
  • Response: None
  • Where:
  • KYx: is the weather condition expected for day x, where x=C is the current weather condition, x=1 is the current day's forecast, x=2 is the next day's forecast, etc.
  • Examples:
    • 5-day weather condition forecast
    • 5-day weather condition forecast with current weather condition.
  • KYC has been added as an optional field to support backwards compatibility with the existing firmware. If a FK command is received without the KYC field, the thermostat should use the current day's forecast (KY1) as the current weather that is shown on the main and current conditions screen. This is identical to the behavior currently implemented in firmware.
  • If a FK command is received with the KYC field, the thermostat should use the KYC value to populate the current weather on the main and current conditions screens.



  • Command: PRESSURE <VAL>
  • Response: None
  • Where:
  • VAL: the barometric pressure. There is no unit conversion in the thermostat, so this value should correspond to the currently used unit of measure.
  • Examples:



  • Command: ?EXTERNAL_TEMP
  • Response: EXTERNAL_TEMP-<TEMP>
  • <TEMP> will be the external temperature in degrees, based on the format set in the device (Celsius or Fahrenheit). If the external sensor is set to Off, the value of <TEMP> should be OFF.



  • Command: MD MPH H<HSP> C<CSP>
  • Response: None
  • Where:
  • HSP: heat setpoint to maintain in degrees in scale set on thermostat
  • CSP: cool setpoint to maintain in degrees in scale set on thermostat
  • Examples:
  • SEND_COMMAND 'MD MPH H72 C75' Permanent Hold, heat setpoint 72F, cool setpoint 75F