HONEYWELL AQ2504B4 Aquatrol Boiler Control Panel for 4 Zone Pumps or Valves. The AQ2504B family of Aquatrol Boiler Controls provides simplified, energy-efficient control of single-temperature, residential hydronic heating systems. It works with the AQ1000T communicating thermostats to convert a single zone heating system into a room-by-room comfort control system, or upgrades a basic relay-logic zoning system to intelligent "zone of greatest demand" control for increased energy efficiency and reduced boiler cycling.

Features:

• Factory configured for control of up to four zones plus domestic hot water.

• Expandable up to 16 zones with expansion zoning modules (sold separately).

• Single stage boiler control synchronized to zone-of-greatest-demand.

• Reduced boiler short-cycling.

• Integral Domestic Hot Water control.

• Installer selectable DHW Priority.

• Installer selectable DHW Priority Override.

• Replacement Parts: AQ1574V4 4-zone valve with end switch expansion module. AQ10X38 24 Vac 38 VA transformer, AQ12C10 outdoor sensor, AQ12C11 supply/return sensor.