PALMETTO, Fla. — Quest Controls Inc.’s Model 400 Controller is designed to work as a stand-alone HVAC control system or work in conjunction with the TELSEC® ESB2 Environmental Controller to provide a comprehensive monitoring and control system for telecom/broadband facilities. Multiple HVAC units can be grouped by the area they serve to provide lead/lag/standby functionality per zone. 

HVAC systems with economizers can take advantage of Quest’s patented economizer control algorithm to maximize the amount of time outside air can be used to maintain the temperature in each zone. One outside air sensor can be shared with all Model 400 units. The Model 400 Controller provides the necessary redundancy for critical facilities while providing optimization that reduces the energy consumption of the HVAC equipment. Up to 16 Model 400 HVAC Controllers can be networked to the TELSEC® ESB2.


Model 400 HVAC Controller Features

  • Can be configured to control most HVAC systems such as single stage, two stage, or heat pump systems.
  • Designed to work with existing HVAC economizer control modules or take direct control of the outside air damper.
  • Supports variable speed control of the supply air fan.
  • Powered from the HVAC’s 24VAC transformers.
  • Additional 24VDC power source supported.
  • Networkable to the ESB2 or any Modbus RTU controller.
  • Works in stand-alone mode if communications are lost.
  • LCD shows the current operating mode and temperature readings.
  • Five button keypad for navigation to other status screens.
  • Default settings and configuration are settable through password-protected screens.
  • All settings can be modified remotely through Modbus RTU.
  • Built-in zone temperature for ease of installation.
  • Additional zone sensor can be added for controlling based upon the average or high of the two sensors.


For more information, visit