Honeywell AQ25A Series Technical Reference Booklet page 74

AQ251 SERIES BOILER RESET CONTROL PANELS
DOMESTIC HOT WATER
Wire the DHW (terminals 13 and 14) to the Aquastat or
thermostat on the domestic hot water tank.
DHW priority allows only DHW heat for the first 30 minutes of a
call for DHW and then allows the space heating needs to be
added in for the next 30 minutes. This cycle continues until the
call for DHW is satisfied.
NOTE: If the AQ251 is connected to a modulating
condensing boiler with built-in DHW management, the
DHW tank's Aquastat should be connected to the
AQ251's DHW (terminals 13 and 14). The AQ251's
Aux. Out (terminals 19 and 20) should be wired to the
boiler's DHW input terminals to the AQ251. In this
case, the Aux Out contacts should be programmed (in
Installer Mode settings) to close when there's a call
for DHW [EQUIPMENT SETUP>AUXILIARY IO>
AUX.OUT>DHW]
Low Voltage Outputs Wiring
10 VDC
The 10 Vdc terminals (15 and 16) of the AQ251 produce a
modulating (0-10 Vdc or 2-10 Vdc) signal that can drive a
modulating boiler's combustion fan to maintain a constant
supply temperature from the boiler (generally equal to the
Boiler High Limit setting in the EQUIPMENT SETUP > BOILER
SETTINGS sub-menu).
Boiler Signal: If the AQ251 panel is configured to send a
0-10V or 2-10V signal to a modulating/condensing
boiler, connect the AQ251's modulating output terminals
(15 and 16) to the modulating signal input on the boiler
control.
BOILER
Wire the Boiler dry contact output (terminals 17 and 18) to the
T-T terminals on the boiler Aquastat or the boiler's control
panel. See Fig. 15 on page 12 for wiring connections to a
typical boiler Aquastat.
69-1974—04
DATA BUS
COMMUNICATION
WIRING
Menu
OK
Zone 1
Home
AQ25142B
Fig. 8. Wiring for communication bus.
8
These contacts are made any time the system has a request
for boiler operation, unless the water supply temperature is
above the target temp at that time, at which time the system
primary boiler pump would come on.
AUX-OUT
If the Auxiliary Out low voltage output will be used, wire it now
to the device that will be switched when the Auxiliary Out's dry
contacts close. Wire the hot leg of the device through the Aux.
Out connection (terminals 19 and 20).
The Aux-Out relay contacts close to correspond with an action
as determined by the installer setup using the EQUIPMENT
SETUP > AUXILIARY I/O sub-menu (see Fig. 25 on page 39).
NOTE: The Aux. Out contacts are rated for low voltage
devices only.
Communication Bus Wiring
All AQ2000 components communicate with each other on the
AQUATROL network using communication bus wiring. This
wiring must connect all AQ2000 components. Otherwise,
features that depend on this networked communication (e.g.,
zone synchronization, outdoor temperature displayed on
thermostats, etc.) will not function.
The communication bus wiring is polarity insensitive. The
installer does not need to worry about a +ve or –ve orientation
of the wires. If there are two wires connected between the B-B
Bus Exp. In on one module and B-B Bus Exp. Out on another
module, there will be communication. See example in Fig. 8 for
how this wiring is to be installed.
The communication bus connections for AQ251 Control
Panels are pre-wired at the factory. If connecting an Expansion
Zoning Panel to an AQ25110B, wire the Control Panel's B-B
"Exp.Bus" terminals (21-22) to the B-B "Exp. Bus IN" terminals
(3-4) of the Expansion Zoning Panel.
Zone 2 Zone 3 Zone 4
Zone 1
Zone 2 Zone 3 Zone 4
AQ25744B
M27740A