Honeywell AQ25A Series Technical Reference Booklet page 153

AQ25400B "Add-A-Temperature"
Expansion Control Panel
PRODUCT DESCRIPTION
The AQ25400B "Add-A-Temperature" Expansion Control
Panel provides additional zoning capacity for an existing
hydronic installation controlled by an AQ2000 Series Boiler
Control Panel such as an AQ250 Relay Boiler Control, an
AQ25A Programmable Boiler Control, an AQ251 Reset Boiler
Control, or an AQ252 Universal Injection/Mixing Boiler Reset
Control. The AQ254, which can control up to 16 zones of
heating in addition to the zones connected to the Master
AQ2000 Series boiler control, maintains the water
temperature in a secondary loop of a hydronic system by
mixing higher temperature water from the primary (boiler) loop
with cooler water returning from the heat emitters in the
secondary loop that is being controlled by the AQ254.
The mixing action is accomplished by one of three outputs on
the AQ254's Control Module:
• a line voltage injection pump,
• a 24 Vac floating action motorized mixing valve, or
• a 0-10 Vdc (or 2-10 Vdc) modulating output (for a
motorized mixing valve or variable speed pump). The
floating action mixing valve can be either a rotary or globe
style design.
FEATURES
The AQ25400B has the following features:
• Controls one mixed temperature loop.
• Outdoor temperature compensation (reset), or Load
reset based on indoor temperature feedback, or none.
• Zone synchronization through Zone of Greatest
Demand control.
• Customizable control settings allow for greater level of
control and comfort.
• Use of variable speed injection pump or motorized
mixing valve for mixed temperature loop control.
________________________________________________
IMPORTANT
To ensure correct installation and proper operation of
the control, perform the 6 installation steps in the
order numbered in the "Contents" below.
Specifications ...................................................................
1 Installation Preparation ..................................................
2 Wiring Procedure ...........................................................
3 Program and Configure the Expansion Control Panel ...
4 Test and Check Out the Installation ............................... 11
5 Purge Air from all System and Zone Piping .................. 12
6 Document and Keep a record of all System Settings .... 12
Troubleshooting ................................................................ 13
Appendix .......................................................................... 14
Home Page and System Status Page .................... 14
Installer Programming Menu .................................. 15
PRODUCT DATA
Contents
2
3
5
9
69-1987-02