Onyxx® LX BW437

Configurable Thermostat for FCU

The BW437-FCU-LX is a compact, BACnet® MS/TP thermostat that includes programs for most FCU applications. Configuration is made simple using the menu-driven keypad, or a BACnet monitor, like the freeware Onyxx® LX UI (requires a separate special USB adapter), or even a Niagara host. This application specific, BTL Certified HVAC controller is available with motion, humidity, and CO2 sensing options.


  • Factory-delivered pre-loaded with a powerful low voltage FCU controller application
  • Supports BACnet MS/TP
  • Has 4 AI/BI’s, 3 AO’s, 6 BO’s plus 1 jumper-selectable universal AO/BO
  • Options include Humidity sensor, PIR & CO2 sensing.
  • Certified as a B-ASC (BACnet Application Specific Controller)
  • Requires Onyxx LX USB to RS-485 adapter to program with Onyxx LX UI
  • BTL Certified as a B-ASC (BACnet Application Specific Controller) BACnet is a registered trademark of ASHRAE. ASHRAE does not endorse, approve, or test products for compliance with ASHRAE standards. Compliance of listed products to the requirements of ASHRAE Standard 135 is the responsibility of BACnet International. BTL is a registered trademark of BACnet International.
  • To order use part numbers as per table below:
Model Number
Built-In Humidity Sensor
Built-In PIR Motion Sensor
Built-In CO2 NDIR Sensor


This controller is designed to facilitate control and management of equipment typically used in the HVAC industry. It allows powerful yet flexible solutions that can be tailored and sized according to any project needs. It features a very flexible I/O set capable of meeting all terminal equipment control needs in the market.