Calibrating Airflow on a Xenta 102-AX (or MR-VAV-AX) using the M/STAT

Issue

  • Step-by-step instructions for calibrating airflow on a Xenta 102-AX (or I/NET MR-VAV-AX) using the M/STAT.
  • Test and air balance procedure for balancing airflow

Product Line

TAC I/NET, TAC Vista, SmartStruxure Solution

Environment

  • Xenta 102-AX
  • MR-VAV-AX
  • M/STAT

Cause

The preferred method for calibrating airflow in Xenta 102-AX or MR-VAV-AX is through the plug-in.  However, this is not always an option, especially when the responsibility for calibrating is given to a third party test and balance company.  Pocket references exist for navigating through the M/STAT menu, but there aren't clear step-by-step instructions to tell exactly how to perform the calibration.

Resolution

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  1. Connect M/STAT
    • Plug the M/STAT into the jack on the thermostat. The initial display shows the set temperature.
  1. Enter Password
    • Press the Service button. This prompts you to enter the service mode password. Default password is 183. Use the +/- keys to set each digit and the enter key to submit. If the password is incorrect, the display will blink.
  1. Airflow Parameters
    • If the password is correct, the first menu option – Unit Parameters (UP) – is displayed. Hit the select button down twice until Airflow Parameters (AP) is displayed. Press enter.
  1. Cooling Low Flow Setpoint
    • The first option is Cooling Low Flow Setpoint (CLF). Press enter to view the setpoint (divided by 1000). Record this value. Press the service key to escape out of the menu.
  1. Cooling High Flow Setpoint
    • Navigate to Cooling High Flow Setpoint (CHF). Press enter to view the value (divided by 1000). Record this value. Press the service key to escape out of the menu.
  1. Reset Factory Calibration
    • Navigate to Factory Calibration Settings (FCS) and press enter. Use the change keys to display “YES” and press the enter key. This will set the box back to default settings. This is a good idea to do prior to every calibration. Press the service key to escape out of the menu.
  1. Calibrate Low Airflow
    • Navigate to Calibrate Low Airflow (CPL). Press enter and the current airflow is displayed. Wait for the airflow to reach the CLF and level out. Once the value is steady at setpoint, press the enter key only once. The display does not change.
  1. Enter Actual Low Airflow
    • Measure the actual airflow. Use the change keys to set the display value to the measured value. Press the enter key.
  1. Choose One or Two-Point
    • Now Calibrate High Airflow (CPH) is displayed. If one-point (offset only) calibration is desired, press the service key to escape out of this mode and calibration is complete. If two-point (gain and offset) calibration is desired, press enter to continue to the next step.
  1. Calibrate High Airflow
    • The current airflow is displayed again. Wait for it to rise to meet the CHF and level out. Once the value is steady at setpoint, press the enter key only once. The display does not change.
  1. Enter Actual High Airflow
    • Measure the actual airflow. Use the change keys to set the display value to the measured value. Press the enter key. CPH is displayed again, this time as a general menu item.
  1. Escape Service Mode
    • Press the service key to escape out of the menu. If you are finished configuring the box, escape all the way back out of the service menu before disconnecting the M/STAT. Disconnecting in configuration mode can leave the stat displaying “00” or other incorrect numbers.