I/A Series MNL-VAV controller continues to display a small air flow value (CFM or L/S) even when airflow is not present (zero flow conditions). This condition is typically seen as small CFM readings on graphics screens when air is not present (AHU off condition).
TAC IA Series
MNL-V1RV3-2, MNL-V2RV3-2, or MNL-V3RV3
The I/A Series MNL-V1, V2, V3 and controller platforms were recently redesigned to incorporate the latest Echelon FT 5000 Neuron Smart transceiver. With no air flow, when the fan system is not running, minor fluctuations in duct pressure could result in false air flow readings from the MNL-V1RV3-2, MNL-V2RV3-2, and MNL-V3RV3.
Use the MNL Firmware Updater Utility to update the MNL-V1RV3-2, MNL-V2RV3-2, or MNL-V3RV3 controller firmware to version 4.3B5. A velocity pressure reading below 0.005 in. WC (1.25 Pa) will be processed within the controller as no or zero flow. Controllers within these date code ranges should be updated with the utility detailed below.
- MNL-V1 and MNL-V3 starting with date codes of 1208
- MNL-V2 starting with date codes of 1212
Note: The MNL VAV control range of 0.05 to 2.00 in. WC (12.5 to 498.2 Pa) is not affected. When air flow control below 0.05 in. WC is required, the I/A Series MNB VAV controllers, with a control range of 0.004 to 1.5 in. WC (1.0 to 373.6 Pa), should be used.
MNL Firmware Updater Utility
The MNL Firmware Updater 4_3B5.zip can be downloaded from The Exchange Download Center. The zip file contains these instructions and the “MNL Updater Setup.exe”. Executing “MNL Updater Setup.exe” will place the latest firmware into C:\Program Files\Schneider Electric\MNL Firmware Updater\bin and add the installer to the Start Menu item under Schneider Electric.
- MNL-V1RV3-2, MNL-V2RV3-2, and MNL-V3RV3 controller firmware version 4.3B5
- MNL-5 controller firmware version 4.3A5
If the MNL Firmware Updater had previously been installed, the MNL-V1RV3.NDL, MNL-V2RV3.NDL, and MNL-V3RV3.NDL files located in "C:\Program Files\Schneider Electric\MNL Firmware Updater\bin" will be replaced.