Choosing components is easy. If you need outdoor temperature compensation or an indoor display of outdoor temperature choose a reset (AQ251) control. The type of equipment - pumps or valves; with or without end switches; the number of zones. Remember an AQ1000 thermostat for each zone
Control Panel Features:

• Line or low-voltage output
• 1-stage zoning
• Zone synchronization
• Boiler short cycling protection
• Boiler post purge
• Freeze protection
• Pump/valve exercise
• Integral domestic hot water management and priority (override) protection - does not use a zone
• Automated test feature for quick start-up and simple troubleshooting
  Reset Features:
• Customizable control settings and schedules allow for greater level of control and comfort
• Outdoor temperature compensation (reset)
• Allows outdoor temperature to be displayed on all thermostats
• Central set-back schedules available
• Automated purge feature for quick start-up and simple troubleshooting
  Expansion Panel Features:
• Armchair programmable (can be programmed at your desk and taken to the job site ready to install)
• R-C transformer and B-B data bus terminal connections and network communication for easy expansion
• Status LCDs for easy diagnostics
• Use with 2-wire "polarity insensitive" communicating thermostats