The AQ255 and AQ257 family of AQUATROL Expansion Zoning panels work with AQ2000 Boiler Control Panels and AQ1000 Communicating Thermostats to control up to 4 space heating zones (or 8, for the AQ25582B Panel). Can be combined with additional expansion zoning panels and an AQ2000 control panel for a total of 16 space heating zones.

  • AQ255 for zoning with pumps or zone valves without end switches.
  • Auto test function to test zones at system start up. It allows for operator controlled testing of zones; includes pause/restart capability.
  • LED lights for visual diagnostic of zone operation.
  • Allows zoning with either "Normally Open" or "Normally Closed" zone valves.
  • Adjacent zoning panels can operate different zone equipment - one panel may control 4 pumps while another may control 4 zone valves.
  • Easily switch from zone valves to pumps with same zoning module - just flip one DIP switch. Ensure correct voltage is applied to all zone equipment on a panel (120 Vac for pumps, 24 Vac for valves)
  • R-C transformer and B-B data bus terminal connections (network communication) for easy expansion.
  • Zones can be set to energize a group pump via Aux Out dry contacts on main control panel (AQ250, AQ25A, AQ251, AQ252) or expansion control panel (AQ254).
  • Zone synchronization through Zone of Greatest Demand control.
  • 38 VA Transformer with self resetting electronic fuse.
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Manuals (1)
Thermostat Compatibility:
AQ1000 Series 2-wire
Most Digital Thermostats
User Interface:
DIP Switch
RC Input:
24 Vac Class II
Zone Output Contact:
120 Vac/250 Vac 5A 1/3 HP
Control Temp Range (F):
32 F to 130 F
Operating Humidity:
5 to 90% RH non-condensing
9-1/2" wide x 8" high x 3 3/8" deep
Zoning Devices Controlled:
2-wire valves
Zone pumps
Electric Connection:
Wire-clamp screw terminals
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