Honeywell AQ251 Series Product Information Sheet
AQ251 Series
Boiler Reset Control Panels
FEATURES
The AQ251 Series has the following features:
• Outdoor temperature compensation (reset), or Load
reset based on indoor temperature feedback, or none
• Domestic hot water (DHW) priority and priority
override protection.
• Customizable control settings and schedules allow for
greater level of control and comfort.
• Central set-back schedules available.
• Zoning Control for up to four, single-stage zones or
two, two-stage zones as shipped; can be expanded to
a total of 16 zones with AQ255 or AQ257 expansion
zoning panels, and up to 64 zones by using up to three
AQ254 Add-a-Temperature expansion panels and
additional expansion zoning modules.
• Use with digital non-communicating thermostats or
AQ1000 2-wire polarity insensitive communicating
thermostats.
PRODUCT DESCRIPTION
The AQ251 Series of AQUATROL® Boiler Reset Controls
provides simplified, energy-efficient outdoor temperature
compensated control of a high-temperature boiler loop in
residential hydronic heating systems. The AQ251 easily
converts a single-zone heating system into a room-by-room
comfort control system. The boiler controls of the AQ251 can
ensure ample supply of hot water for both space heating and
priority generation of domestic hot water for bathing, dishes
and laundry.
Contents
Specifications ................................................................... 2
1 Installation Preparation .................................................. 3
2 Mounting ........................................................................ 5
3 Wiring Procedure .......................................................... 6
4 Program and Configure the Control Panel .................... 14
5 Test and Check Out the Installation ............................... 18
6 Purge Air from all System and Zone Piping .................. 19
7 Document and Keep a record of all System Settings .... 19
Troubleshooting ................................................................ 20
Appendix .......................................................................... 23
User Menu ........................................................................ 23
Installer Menu ................................................................... 30
• When using non-communicating thermostats, the
following features are not available:
• Outdoor temperature is not displayed on the
thermostat.
• Time clock on AQ1000TP2 will not synchronize
with the Control Module.
• Central programming, vacancy and setback
schedules of AQ1000 from AQ panel are not
enabled.
• AQ panel will not display individual zone
temperatures.
• Individual zone freeze protection.
• Allows display of outdoor temperature on all AQ1000
thermostats when used with an AQ12C10 outdoor
sensor (included).
• Intuitive programming interface (can be programmed at
your shop and taken to the job site “ready-to-install”).
• Pump/valve exercise.
• Line or low-voltage output for zoning equipment
(pumps or valves).
• Integral 38 VA transformer with self resetting electronic
fuse.
• Automated test and purge feature for quick start-up
and simplified troubleshooting.
• Two hour power supply module (super capacitor)
retains day and time settings during power outage and
a non-volatile EPROM memory retains program
settings during power outage.
PRODUCT DATA
69-1974-07
AQ251 SERIES BOILER RESET CONTROL PANELS
SPECIFICATIONS
The AQ251 Control Panels and corresponding attached
equipment are listed in Table 1.
Table 1. AQ251 Series Control Panel Models.
Corresponding
Control Panel
AQ25110B AQ15100B none
AQ25142B AQ15100B AQ15540B
AQ25144B AQ15100B AQ15740B
Application: Controls one boiler, as well as domestic hot
water (DHW) management and zoning operation in a
hydronic zoning system.
Power and Electrical Ratings:
Power Supply: 120 Vac / 60Hz
Auxiliary Pump Contact Rating: 120 to 240 Vac, 5A, 1/3
HP
Auxiliary Low Voltage Contact Rating: 24 Vac, 0.5A,
12VA
Boiler (T-T) Contact Rating: 24 Vac, 0.5A, 12VA
Boiler Pump (C1-C2) Output Rating: 120 Vac 5A, 1/3HP
DHW Pump/Valve Output Rating: 120 Vac 5A, 1/3HP
B–B Communication Bus Terminals: Low voltage,
Class II, 2-wire polarity-insensitive, digital
communicating link to other Control or Zoning modules
Electrical Connections (Line Voltage): Wire-clamp
screw terminals; maximum 2 x 14 AWG each on line
voltage terminals
Environmental Ratings:
Control and Zoning Panel Temperature Rating: 32°F to
130°F (0°C to 55°C)
Operating Humidity Range (% RH): 5 to 90% RH, non-
condensing
Temperature Ratings:
Boiler Design Temperature: 80°F to 210°F (26°C to
99°C)
Boiler Differential: 2°F to 41°F (1°C to 23°C), or Auto
Boiler High Limit Control Temperature: OFF, 120°F to
225°F (OFF, 49°C to 107°C)
Boiler Low Limit Control Temperature: OFF, 60°F to
180°F (OFF, 15°C to 82°C)
Control Module
Corresponding
Zoning Module
Outdoor Low Design Control Temperature: -60°F to
32°F (-51°C to 0°C)
Boiler Minimum Return Control Temperature: OFF,
80°F to 180°F (OFF, 27°C to 82°C)
Sensor Temperature Rating: -58°F to 230°F (-50°C to
110°C)
Warm Weather Shut Down (WWSD) Temperature:
OFF, 35°F to 100°F (OFF, 1°C to 38°C)
Cold Weather Shut Down (CWSD) Temperature: OFF,
32°F to 100°F (OFF, 0°C to 38°C)
Inputs/Outputs:
Auxiliary (Demand) Input: External dry contacts
connection only
DHW Demand Input: External dry contacts connection
only
R–C Input (on Control and Zoning Modules): 24 Vac
Class II
R–C Output (on transformer): 38 VA, 24 Vac Class II
Heat Demand Input External dry contacts connection
only
Modulating Output: 0-10 or 2-10 Vdc for variable speed
pump or modulating boiler
Mixing Valve Output (floating, open/close) (dry relay):
24 Vac, 12 VA
Interface and Timings:
User Interface (Setting, Programming): LCD Display
and a 7-button keypad
Setback Program: 7 day, up to 2 setback periods/day.
DHW Valve Open: 0-230 seconds, before boiler loop
pump is energized.
DHW Purge: Yes/No; selects whether purge is applied
after a DHW demand is served
Boiler Heat Post Purge:
(factory default is 30 seconds)
Pump/Valve exercise: 30 seconds per 2 weeks of space
heating inactivity
Thermostat Compatibility: Digital thermostats and/or
AQ1000 Series 2-wire communicating thermostats
Supply/Return Loop Sensor: 10K ohm NTC thermistor at
77°F (25°C) ± 0.5°F (±0.3°C). Lead length: 10 ft. (3.0 m);
up to 500 ft. (150 m) using 18 AWG or larger wire,
beta=3892.
Off, 10 seconds to 30 minutes
ORDERING INFORMATION
When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the
TRADELINE® Catalog or price sheets for complete ordering number. If you have additional questions, need further information,
or would like to comment on our products or services, please write or phone:
1. Your local Honeywell Environmental and Combustion Controls Sales Office (check white pages of your phone directory).
2. Honeywell Customer Care
1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386
3. http://customer.honeywell.com or http://customer.honeywell.ca
International Sales and Service Offices in all principal cities of the world. Manufacturing in Belgium, Canada, China, Czech
Republic, Germany, Hungary, Italy, Mexico, Netherlands, United Kingdom, and United States.
69-1974—07 2
AQ251 SERIES BOILER RESET CONTROL PANELS
WARNING
Outdoor Sensor: 10K ohm NTC thermistor at 77°F (25°C) ±
0.5°F (±0.3°C). Lead length: 15 ft. (4.6 m); up to 500 ft. (150
m) using 18 AWG or larger wire, beta=3892
Dimensions (HxWxD): 8 x 16 1/2 x 3 3/8 in. (20.3 x 42 x
8.5 cm) approximate
1 INSTALLATION PREPARATION
NOTES: Throughout these instructions, the following
terminology conventions are used:
• AQ251 refers to all of the AQ25142B, AQ25144B and
AQ25110B Control Panels. Where there are specific
instructions or details relating to the “-42B”, “-44B”, or
“-10B” Control Panels, the full model number (i.e.
AQ25144B) is used;
• Control Panel refers to an assembled product, consisting of a transformer, Control Module and Zoning
Module, all contained within an AQ2000 panel enclosure;
• AQ255 refers to all of the AQ25542B, AQ25542B,
AQ25582B and AQ25742B Expansion Zoning Panels,
and AQ257 refers to the AQ25744B Expansion Zoning Panel. Where there are specific instructions or
details relating to the “-42B”, “-82B”, “-42B”, or
“-44B” Expansion Zoning Panels, the full model number (i.e. AQ25744B) is used;
• Expansion Zoning Panel refers to an assembled
product, consisting of a Zoning Module and—if applicable—a transformer, contained within an AQ2000
panel enclosure; Expansion Zoning Panels are available in either 4-zone or 8-zone configurations. See
Table 1 in “AQ2000 Series Expansion Zoning Panels”
(form no. 69-1981) for specific models.
• AQ151 refers to the AQ15100B Control Module within an AQ251 Series Control Panel.
• Control Module refers to the component within an
AQ251 Series Control Panel that performs the “master control operations”. See Table 1 for specific models.
• Zoning Module refers to the component within the
AQ251 Series Control Panel that controls zoning
operations;
• AQ155 refers to the AQ15540B Zoning Module and
AQ157 refers to the AQ15740B Zoning Module.
When Installing this Product…
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a
hazardous condition.
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable for
the application.
3. Installers must be trained, experienced, and licensed
service technicians.
4. Follow local codes for installation and application.
5. After installation is complete, check out the product
operation as printed in these instructions.
Risk of electrical shock.
Can cause severe injury, property damage or death.
Disconnect power supply before installation and before
servicing.
Weight: 4.9 lb. (2.3 kg)
Approvals: Canadian Standards Association: Certified, File
No. LR76030
Check That You Have All the Necessary Equipment For a Successful Installation
• AQ2000 Series components:
— AQ251 Control Panel
— AQ Expansion Zoning Panels (if more than four space-
heating zones in the system)
— Digital Thermostats (one for every space-heating zone
being controlled)
• Boiler supply and return temperature sensors and
secondary loop sensor (included with the AQ251 Control
Panel)
• Outdoor temperature sensor (included with AQ251 Control
Panel)
• Low voltage thermostat wire
• Zoning equipment (zone valves or pumps)
Read All Instructions Carefully Before Proceeding
The AQ251 Control Panels are a part of a totally new series of
hydronic controls. And although they - and other AQ2000
system components - are very easy to install and operate, they
are different than other hydronic controls that you have
previously installed. So take a moment to read through this
quick installation guide before
Failure to follow them could damage the product or cause a
hazardous condition.
beginning the installation.
Familiarize Yourself With the AQ251 Control Panel Layout
Refer to Fig. 1. All AQ251 Control Panels consist of three
functional components:
1. AQ10X38 transformer (power supply module), which
connects to 120 Vac power and supplies 24 Vac power to
the Control Module and Zoning Modules
2. AQ15100B boiler/DHW Control Module, which controls
the boiler and domestic hot water (DHW) functions, as
well as coordinating the overall operation of the hydronic
system.
3. One of two different 4-zone Zoning Modules:
• AQ15740B (part of the AQ25144B Control Panel) for
zoning with 24 Vac zone valves with
• AQ15540B (part of the AQ25142B Control Panel) for
zoning with either line voltage circulators or 24 Vac
zone valves without
AQ251 Control Panels can control a maximum of 16 zones by
connecting additional Expansion Zoning Panels to the AQ251
Control Panel. Each Expansion Zoning Panel is configured with
its own bank of DIP switches, located in the left-most section of
each Zoning Module.
end switches.
end switches
3 69-1974—07
AQ251 SERIES BOILER RESET CONTROL PANELS
Menu
Home
OK
M27736A
Zone 1
Zone 2
Zone 3
Zone 4
LOW
VOLTAGE
(24 V)
LINE
VOLTAGE
(120 V)
ZONING MODULE
TRANSFORMER
CONTROL MODULE
FOR THE AQ25142B TERMINALS CAN BE LINE VOLTAGE (IF USED WITH PUMPS) OR LOW VOLTAGE (IF USED WITH ZONE VALVES)
1
1
Menu
Home
OK
M27737A
Zone 1
Zone 2
Zone 3
Zone 4
CONTACTS
SYMBOL
In general, the top terminals of the AQ2000 Series
components carry low voltage (24 Vac) power and the bottom
terminals carry line voltage (120 Vac) power. This is illustrated
in Fig. 1. The only exception to this is the AQ15540B Zoning
Module when used with low voltage zone valves (without end
switches). In this case, the bottom terminals of the Transformer
and Control Module carry line voltage (120 Vac), but the
bottom terminals of the Zoning Module will carry low voltage
(24 Vac) power.
The powered terminals on the bottom of the AQ2000 Series
Control Modules and Zoning Modules are connected internally,
as shown in Fig. 2. The voltage supplied to the N and L
terminals is also available at the adjacent terminal pairs when
the hot ( ) relays are switched.
Fig. 1. AQ251 Control Panel layout (AQ25142B shown).
Fig. 2. Internal wiring for AQ2000 Series components line voltage relays.
69-1974—07 4
2 MOUNTING
M23733A
WIRE
CHANNEL
PLUGS
WIRE
CHANNEL
PLUGS
AQ251 SERIES BOILER RESET CONTROL PANELS
This section describes how to mount the Control Panel,
Expansion Zoning Panels, and the Thermostats.
Mount AQ251 Control Panel
Mount the control panel on the wall:
1. Use the template supplied with the AQ251 Series
Control Panel to mark mounting holes for panels
2. Install two top screws, mount the panel, and install the
two lower screws.
Mount Expansion Zoning Panel(s)
If there are Expansion Zoning Panels to install, mount them to
the wall now:
1. Remove wire channel plugs from the AQ251 Control
Panel and any Expansion Zoning Panels (see Fig. 3).
2. Mount Expansion Zoning Panel on the right-hand end of
the AQ251 Control Panel. Install two top screws of the
Expansion Zoning Panel, ensuring it is level with the
adjoining Control Panel, and install two lower screws.
3. Reverse wire channel plugs and re-insert them into their
slot, to form a wiring channel between the Control Panel
and the Expansion Zoning Panel (see Fig. 3) and to
connect the two panels together.
4. Repeat steps 1–3 for any additional Expansion Zoning
Panels.
Fig. 3. Orientation of wire channel plugs for creating pass-through wire channel and
for joining Control Panel to Expansion Zoning Panels.
Mount and Wire Thermostats in the Zones
Install the thermostats on the walls in the zones that are to be
controlled by the AQ251 Control Panel.
When using AQ1000 thermostats refer to the installation
instructions (form #69-2005) included with the AQ1000
thermostats.
If not done already, run low voltage thermostat wire (24 gauge
or heavier) from the thermostats back to the Zoning Modules
connected to the AQ251 Control Panel.
NOTES: If not otherwise specified, low voltage wiring should
be run with 18 gauge thermostat wire and line voltage
wiring should be run with 14 gauge wire.
AQUATROL® line voltage screw terminals are only
approved for use with 22 to 12 gauge copper
conductors.
Several wiring diagrams are included in this
document. For additional information, refer to
http:// customer.honeywell.com or your local
distributor.
5 69-1974—07
AQ251 SERIES BOILER RESET CONTROL PANELS
M27738A
Menu
Home
OK
Zone 1
Zone 2
Zone 3
Zone 4
STEP 1 STEP 2 STEP 3
STEP 4STEP 5STEP 6
TO EXPANSION ZONING MODULES
(IF INSTALLED)
3 WIRING PROCEDURE
The AQ251 Control Panel is pre-wired at the factory, making for
faster installation:
• For all models, the low voltage output terminals located at
the top of the transformer are wired to the R and C input
terminals of the Control Module.
• For those Control Panel models that come with Zoning
Modules included, (all but the AQ25110B), the transformer’s
low voltage outputs are also wired to the R and C inputs of
the Zoning Module. The B-B “Exp. Bus” terminals of the
Control Module are wired to the B-B “Exp. Bus IN” terminals
of the Zoning Module.
Beginning with the top left of Fig. 4 and moving clockwise
around the panel, wire components to the AQ251 Control
Panel and Expansion Zoning Panels (if installed) in the
following six steps:
• “Step 1 – Transformer Wiring”
• “Step 2 – Control Panel Wiring”
• “Step 3 – Thermostats Wiring” on page 9
• “Step 4 – Zoning Equipment Wiring” on page 9
• “Step 5 – Line Voltage System Outputs” on page 12
• “Step 6 – Connection to Line Voltage Power” on page 13
Fig. 4. Wiring sequence.
Step 1 – Transformer Wiring
Factory pre-wiring of the Control Panels is shown as dotted
lines in Fig. 4.
In addition to the pre-wiring, run low voltage jumper wires from
available R and C terminals on the secondary of the
transformer to the R and C terminals of any Expansion Zoning
Panel.
TO SETPOINT LOAD
TO AUXILIARY INPUT
TO BOILER SUPPLY SENSOR
IN FROM “R” TERMINAL ON
TRANSFORMER MODULE
(FACTORY-WIRED)
IN FROM “C” TERMINAL
ON TRANSFORMER MODULE
(FACTORY-WIRED)
TO BOILER RETURN SENSOR
TO OUTDOOR SENSOR
SWITCH (OPTIONAL)
TO DHW AQUASTAT
(OPTIONAL)
Step 2 – Control Panel Wiring
Wire the Temperature Sensors, System Demands, Low
Voltage Outputs, and Communication Bus (Refer to Fig. 5 for
wiring terminals on the top of the AQ251):
• “Temperature Sensor Wiring” on page 7
• “System Demands Wiring” on page 7
• “Low Voltage Outputs Wiring” on page 8
• “Communication Bus Wiring” on page 8
TO LOW VOLTAGE AUXILIARY
DEVICE (OPTIONAL)
TO B-B “EXP.BUS IN”
TO MODULATING INPUT
ON BOILER
TO “T-T” TERMINALS ON
BOILER AQUASTAT
TERMINALS ON CONNECTED
ZONING MODULE
M27739A
Fig. 5. Low voltage wiring for the AQ15100B Control Module.
69-1974—07 6
Temperature Sensor Wiring
M13763
M13775
Connect the lead wires of each sensor to the corresponding
terminals on top of the AQ151 Control Module. See Fig. 5 on
page 6.
The Boiler Supply, Return and Secondary loop sensors can be
installed either as strap-on sensors or inserted into an
immersion well that is packed with thermally-conductive paste.
BOILER SUPPLY AND RETURN SENSORS.
Both
the Supply and Return Sensors should be installed on the
supply and return piping of the boiler for proper operation of the
AQ251 Control Panel. Even if the AQ251 is connected to a
modulating condensing boiler with its own supply and/or return
sensors, the AQ251’s sensors should still be installed for the
control to operate.
The Boiler Supply water sensor should be installed on the
supply piping close to the exit port of the boiler, using one of
the AQ12C11 strap-on sensors supplied with the AQ251. See
Fig. 6.
The Boiler Return sensor should be installed on the return
piping as close to the entrance port to the boiler as practical,
using the other AQ12C11 strap-on sensor supplied with the
AQ251.
The correct location is one that will measure the temperature of
all combined sources of water returning back to the boiler.
Insulate strap-on sensors with pipe wrap to ensure accurate
boiler temperature sensing.
The Boiler Supply and Return water sensors come with 10 ft.
(3m) of wire to minimize the need for splicing.
AQ251 SERIES BOILER RESET CONTROL PANELS
Fig. 7. Outdoor temperature sensor installation.
IMPORTANT
Do not run sensor wires parallel, or close, to
telephone, Ethernet, or power cables. Cross all
power, Ethernet, and telephone wiring at right angles.
If sensor wires are located in an area with strong
sources of electromagnetic interference, or EMI, (e.g.,
if sensor wires are run in the same electrical chase as
line voltage wiring) use twisted pair, shielded cable, or
run wires in a grounded metal conduit. This is
important, since the calculated temperature - based
on the sensor's resistance reading - can be distorted
by high EMI, potentially causing the AQ251 to not
operate properly. If using shielded cable or conduit,
connect the shield wire to earth ground only
AQ251 panel. Do not
ground the shield or conduit at
any other location or electromagnetic shielding will be
ineffective. If shielded cable is used, Honeywell
recommends the use of shielded cable with a
continuous ground plane, such as foil, with an integral
drain wire for bonding to earth ground.
at the
Fig. 6. Strap-on temperature sensor installation.
OUTDOOR SENSOR
The outdoor sensor should be located:
• in a shady location out of direct sunlight
• at least three feet from dryer, bathroom, or other vents
• above the expected snow line where ice and debris cannot
cover it
• on the north side of the building.
See Fig. 7 for typical placement. Outdoor sensor comes with
10 ft. (3m) of wire to facilitate splicing the sensor on the interior
of the building. Alternatively, if the building is equipped with a
continuous fresh air supply using, for example, an air-to-air
heat exchanger, the outdoor sensor may be installed in the
insulated portion of the ventilation intake duct, taking care not
to expose the sensor to direct or indirect sunlight.
System Demands Wiring
Additional information about settings for the various System
Demands is discussed in Table 6 on page 30.
AUX-IN
If the optional Aux In. contacts (terminals 9 and 10) will be
used, wire them now. These inputs are powered with 24 Vdc
and must connect only
switch).
The Aux-In contact closure sets the system into a specific
state, as determined by the installer setup using the
EQUIPMENT SETUP > AUXILIARY I/O sub-menu (see
Fig. 25 on page 39).
HEAT DEMAND
If the optional Heat Demand (terminals 11 and 12) will be used,
wire them to a system setpoint demand (dry contact closure),
such as a pool or spa Aquastat®.
The HEAT contact closure drives the system to control either at
the Reset temperature or the Setpoint temperature, as
determined by the installer setup using the EQUIPMENT
SETUP > ZONING > HEAT DMND selection (see Fig. 25 on
page 39). Heat Demand priority allows only heat for the first 30
7 69-1974—07
to a dry closure contact (unpowered
AQ251 SERIES BOILER RESET CONTROL PANELS
minutes of a call for heat and then allows the space heating
needs to be added in for the next 30 minutes. This cycle
continues until the call for heat is satisfied.
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.
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
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.
connect all AQ2000 components. Otherwise,
Menu
OK
Home
AQ25142B
Fig. 8. Wiring for communication bus.
69-1974—07 8
DATA BUS
COMMUNICATION
WIRING
Zone 1
Zone 3
Zone 2
Zone 4
AQ25744B
Zone 1
Zone 2
Zone 3
M27740A
Zone 4
AQ251 SERIES BOILER RESET CONTROL PANELS
FROM B-B “EXP. BUS”
TERMINALS ON
CONTROL MODULE
TO B-B “EXP. BUS IN” TERMINALS
ON CONNECTED ZONING MODULE
(IF AN EXPANSION ZONING PANEL
IS CONNECTED)
THERMOSTAT ON ZONE 1 THERMOSTAT ON ZONE 2
THERMOSTAT ON ZONE 3 THERMOSTAT ON ZONE 4
M13776C
A
M27688A
Step 3 – Thermostats Wiring
NOTE: The new AQ2000 panels will work with either digi-
tal (electronic) non-communicating thermostats
or AQ1000 communicating thermostats.
1. Using low voltage thermostat wire, connect one
thermostat from each zone to the corresponding
THERMOSTATS Zone X inputs on top of the Zoning
Module (see Fig. 9).
2. If there are additional zones (on Expansion Zoning
Panels) connected to this Zoning Module, run low
voltage thermostat wiring from the B-B Exp. Bus Out
connection (terminals 13 and 14) of the Zoning Module
to the B-B Exp. Bus. In connection (terminals 3 and 4) on
the Expansion Zoning Panel.
IMPORTANT
Do not run thermostat wires parallel, or close, to
telephone, Ethernet, or power cables. Cross all
power, Ethernet, and telephone wiring at right angles.
If thermostat wires are located in an area with strong
sources of electromagnetic interference, or EMI, (e.g.,
if thermostat wires are run in the same electrical
chase as line voltage wiring) use twisted pair,
shielded cable, or run wires in a grounded metal
conduit.
This is important, because the AQ1000 thermostats
are communicating thermostats which send and
received data via the two wires connecting them to
the Zoning Module. This data can be distorted by the
EMI, potentially causing the AQ251 to not operate
properly.
3. Run low voltage thermostat wiring from the R and C
terminals on the AQ251 Control Panel’s transformer to
the R and C terminals on the Expansion Zoning Panel.
As an alternative, you can run low voltage thermostat
wiring from the R and C terminals on the Zoning Module
to the R and C terminals on the Expansion Zoning Panel.
Step 4 – Zoning Equipment Wiring
Because the Zoning Module of the AQ25142B Control Panel
can be used with either low voltage zone valves (without end
switches) or line voltage pumps or valves, field installed wiring
of the correct voltage needs to be connected to the zoning
equipment terminals on the bottom left portion of the Zoning
Module.
Line Voltage – Circulators or Zone Valves
Refer to Fig. 10. Remove the plastic wiring barrier that is
located in the bottom wiring channel between the AQ15100B
Control Module and the Zoning Module. Run jumper wires from
the N and L terminals on the bottom of the AQ251 Control
Panel’s transformer, through the wiring channel across the
bottom of the Control Panel, and to the corresponding N and L
terminals of the Zoning Module.
FROM LINE VOLTAGE
120V TERMINALS
(N AND L) ON BOTTOM
OF TRANSFORMER
Fig. 10. Wiring an AQ15540B Zoning Module for use
with line voltage circulators.
Low Voltage – Zone Valves With or Without
End Switches
Wire using step 1 for zone valves without end switches, or use
step 2 for zone valves with
1. Low voltage zone valves without
Using Fig. 12 on page 10 as a guide, run jumper wires
from the R and C terminals on the secondary of the
AQ251’s transformer, through the wiring channel across
the top of the Control Panel, and down through the wiring
channel on the right side of the panel and over to the R
and C terminals on the bottom of the Zoning Module.
end switches:
end switches:
M27687
Fig. 9. Connecting AQ1000 thermostats.
IMPORTANT
If low voltage zone valves are used with the
AQ25142B Control Panel, the supplied Low Voltage
Output sticker (shown in Fig. 11) must
be applied
over the line voltage output sticker (see Fig. 10) that is
already attached to the Zoning Module.
Fig. 11. Low voltage output sticker.
9 69-1974—07
AQ251 SERIES BOILER RESET CONTROL PANELS
CAUTION
FROM LOW VOLTAGE
24 VAC TERMINALS
(C AND R) ON TOP
OF TRANSFORMER
M M M M
M27689A
Fig. 12. Wiring an AQ15540B Zoning Module for use
with low voltage zone valves without
end switches.
2. Low voltage zone valves with end switches:
See Fig. 13. 24 Vac power is pre-wired between the
transformer secondary at the top left of the AQ251’s
transformer and the AQ15740B Zoning Module. No field
wiring is required.
M
M
M
M
Fig. 13. Wiring an AQ15740B Zoning Module for use
with low voltage zone valves with
end switches.
M27690A
NOTE: When wiring zone valves with end switches, note
the transformer's VA:
If low voltage zone valves with end switches are
used for zone control, make sure the selected
zone valves do not draw more power (VA) than the
38 VA capacity of the AQ10X38 transformer
supplied with the AQ251 Control Panel. This
integral transformer has enough power to operate
4 motorized zone valves (such as Honeywell
V8043E valves or 4 valves using low-amperage
draw, heat motor actuators, such as Honeywell
MV100 actuators), plus power the electronics of
the AQ251's Control Module and up to 16, AQ1000
thermostats. If zone valves with high-amperagedraw heat-motor actuators are used (such as Taco
500 series zone valves), additional 24 Vac
transformer capacity will need to be wired to the
Zoning Module to power the valves. See
Fig. 14 on page 11 for recommended wiring of
additional low voltage VA capacity to AQ2000
Series Zoning Modules.
Equipment Damage Hazard.
Can damage internal circuitry of Zoning Module.
The ES1 and ES2 terminals of the AQ15740B Zoning
Module are powered terminals and must only
be
connected to a set of dry contacts, such as a zone
valve motor's end switch. If power is applied to these
contacts (for example, by running line voltage through
the zone valves’ end switches to bring on a circulator
feeding those valves), the internal circuitry of the
Zoning Module will be damaged, in which case the
warranty for this product will be voided.
69-1974—07 10
AQ251 SERIES BOILER RESET CONTROL PANELS
THERMOSTATS
ZONE 1 ZONE 2 ZONE 3
ZONE 4
M27741A
THERMOSTATS
ZONE 1 ZONE 2 ZONE 3
ZONE 4
Zone 1
Zone 2
Zone 3
Zone 4
USING AN AQ15740B
VALVE ZONING MODULE
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
1
Zone 1
Zone 2
Zone 3
Zone 4
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
24 VAC
100 VA
TRANSFORMER
115 VAC
115 VAC
24 VAC
100 VA
TRANSFORMER
1
1
USING AN AQ15540B
PUMP ZONING MODULE
Fig. 14. Wiring of additional low voltage VA capacity.
11 69-1974—07
AQ251 SERIES BOILER RESET CONTROL PANELS
ZC
ZR
B1
B2
C1
C2
L1
L2
TT
G
L8148, L7148
R8184A, R7184
BURNER AND
IGNITION
C554
F
F
T
T
BLACK
WHITE
ORANGE
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
L1
(HOT)
L2
1
1
TO AUXILIARY DEVICE
(INSTALLER-DEFINED)
BOILER
PUMP
M27742A
N
L
TO LINE VOLTAGE 120V
TERMINALS (N AND L) ON
BOTTOM OF TRANSFORMER
FROM LINE VOLTAGE 120V
TERMINALS (N AND L) ON
BOTTOM OF TRANSFORMER
TO BOILER
TERMINALS 17-18
ON TOP OF AQ15100B
CONTROL MODULE
Step 5 – Line Voltage System Outputs
Refer to Fig. 15 and follow the steps in this section to wire
these devices to the AQ251 Control Module.
“1. Boiler Pump”
“2. DHW Device”
“3. Line Voltage Rated Aux Output (Aux. pump)” on page 13
1. Boiler Pump
Connect the N and L wires of the boiler loop pump to the N and
switched hot terminals of the line voltage Boiler output, shown
in Fig. 17 on page 13. The ground wire of the pump can be
connected to any of the 8 ground screw terminals located on
the back surface of the Control Panel enclosure.
The boiler pump contacts are made after any one of the
following occur:
• A call for heat has occurred from any heating zone.
• The Heat input is shorted on terminals 11 and 12.
• The DHW input is shorted and
as a valve.
The pump is delayed for the FIRE DELAY programmed in the
EQUIPMENT SETUP > BOILER OPERATION sub-menu (see
Fig. 25 on page 39). The boiler pump and the last zone calling
remain on in order to move heat out of the boiler for the period
of time programmed in the Purge time menu under the fire
delay. Manually adjusting thermostats affects the operation of
this software so it can not be tested manually, you must
observe it under normal operating conditions.
NOTE: If the AQ251 is connected to a modulating
69-1974—07 12
Fig. 15. Line Voltage Connections for AQ251.
the DHW type is configured
condensing boiler, the boiler pump may need to
be connected to the boiler, not
the AQ251.
Confirm this with the boiler’s installation manual.
2. DHW Device
Wire the DHW pump or line voltage zone valve to the N and
switched hot terminals of the DHW output, as shown in
Fig. 17 on page 13.
If using a low voltage zone valve, wire the primary of a spudmounted transformer (115V to 24V) to the DHW line voltage
contacts and connect the low voltage zone valve to the
secondary terminals of this transformer. A spud-mounted
transformer may be located in one of the conduit knockouts on
the bottom of the AQ251 Control Panel.
Alternatively, a 24 Vac zone valve can be connected to the Aux.
pump line voltage-rated dry contacts, which can be configured
to close on a DHW call. This configuration is defined in the
Installer Equipment Setup menu beginning on page 30.
The DHW contacts are made when the DHW inputs on
terminals 13 and 14 are shorted by the controlling Aquastat.
This is a line voltage output designed to go to the DHW pump.
If 24 Vac is needed for a low voltage valve, you can mount a
step-down transformer on the conduit opening and wire the
valve from the transformer. When DHW is enabled, the system
has a 30-minute priority over all calls for heat. After 30 minutes,
calls for heat are added back in to the operation for 30 minutes
and then turned off again. This repeats until the DHW is
satisfied.
Loading...