Honeywell AQ254 Series User manual

PRODUCT DATA
68-0306-07
AQ250 Series
Hydronic Control Panels
PRODUCT DESCRIPTION
The AQ250 easily converts 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. The boiler control of the AQ250
can ensure ample supply of hot water for both space
heating and priority generation of domestic hot water for
bathing, dishes and laundry.
FEATURES
The AQ250 Series Hydronic Control Panels have the
following features:
• 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.
• Controls one boiler loop.
• Zone synchronization through Zone of Greatest
Demand control.
• Domestic hot water (DHW) priority and priority
override protection.
• Use with digital non-communicating thermostats or
AQ1000 2-wire polarity insensitive communicating
thermostats.
• Automated test feature for quick start-up and
simplified troubleshooting.
• Boiler freeze protection (in the event of network
communication failure).
• Boiler short cycling protection, post purge, and shock
prevention from cold water returning to boiler.
• Line or low-voltage output for zoning equipment
(pumps or valves).
• Integral 38 VA transformer with self resetting
electronic fuse.
IMPORTANT
To ensure correct installation and proper operation
of the control, perform the 7 installation steps in
the order numbered starting with “Installation
Preparation” on page 3.
• When using non-communicating thermostats, the
following features are not available:
• Outdoor temperature is not displayed on the
thermostat.
• Individual zone freeze protection.

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 2
SPECIFICATIONS
The AQ250 Control Panels and corresponding attached
equipment are listed in Table 1.
Table 1. AQ250 Series Control Panel Models.
Application: Controls one boiler loop 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: 120/250 Vac, 5A,
1/3 HP
Boiler (T-T) Contact Rating: 24 Vac, 0.5A, 12 VA
Boiler Pump Output Rating: 120 Vac, 5A, 1/3 HP
DHW Pump/Valve Output Rating: 120 Vac, 5A, 1/3 HP
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:
Return Minimum Control Temperature: 140°F
(60°C); This is the temperature at which the bypass
pump (Aux. Pump contacts) is activated.
Sensor Temperature Rating:
-58°F to 230°F (-50°C to 110°C)
Inputs/Outputs:
DHW Demand Input: External dry contacts
connection only
Heat Demand (Thermostat R-W) 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
Interface and Timings:
User Interface: DIP Switch settings
Boiler Heat Post Purge: 30 seconds; not adjustable
Pump/Valve exercise: 30 seconds per 2 weeks of
space heating inactivity; not adjustable
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.
Dimensions (HxWxD):
8.0 x 13 x 3.3 in. (20.3 x 32.9 x 8.5 cm) approximate
Weight: 4.9 lb. (2.2 kg)
Approvals: Canadian Standards Association: Certified,
File No. LR76030
Control Panel
Corresponding
Control Module
Corresponding
Zoning Module
AQ25042B AQ15000B AQ15540B
AQ25044B AQ15000B AQ15740B

AQ250 SERIES HYDRONIC CONTROL PANELS
368-0306—07
1 INSTALLATION PREPARATION
NOTES: Throughout these instructions, the following
terminology conventions are used:
— AQ150 refers to the AQ15000B Control Module;
— AQ155 refers to the AQ15540B Zoning Module.
— AQ157 refers to the AQ15740B Zoning Module.
— AQ250 is used when the information applies to
both the AQ25042B and AQ25044B Control Pan-
els. Where there are specific instructions or details
relating to the “-42B” or “-44B” Control Panels, the
full model number (i.e. AQ25044B) is used;
— AQ255 refers to all of the AQ25542B, AQ25582B
and AQ25742B Expansion Zoning Panels
— 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;
— Control Module refers to the component within an
AQ2000 Series Control Panel that performs the
master control operations. See Table 1 on page 2
for specific models.
— Control Panel refers to an assembled product, con-
sisting of a transformer, Control Module and Zon-
ing Module, all contained within an AQ2000 panel
enclosure;
— Expansion Zoning Panel refers to an assembled
product, consisting of a Zoning Module and, if
applicable, a transformer, contained within an
AQ2000 panel enclosure. Zoning Modules are
available in either 4-zone or 8-zone configurations.
Refer to literature Form No. 69-1981 for more
information on these products.
— Zoning Module refers to the component within an
AQ2000 Series Control Panel or Zoning Expansion
Panel.
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.
WARNING
Risk of electrical shock.
Can cause severe injury, property damage or
death.
Disconnect power supply before installation and
before servicing.
Check That You Have All the
Necessary Equipment For a
Successful Installation
• AQ2000 Series components:
— AQ250 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 (included
with the AQ250 Control Panel)
• Low voltage thermostat wire
• Zoning equipment (zone valves or pumps)
Read All Instructions Carefully
Before Proceeding
The AQ250 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
beginning the installation. Failure to follow them could
damage the product or cause a hazardous condition.
Familiarize Yourself With the
AQ250 Control Panel Layout
Refer to Fig. 1 on page 4. All AQ250 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. AQ15000B boiler / DHW Control Module, which
controls the boiler and domestic hot water (DHW)
functions as well as coordinating the overall opera-
tion of the hydronic system.
3. One of two different 4-zone Zoning Modules:
• AQ15740B (part of the AQ25044B Control
Panel) for zoning with 24 Vac zone valves with
end switches.
• AQ15540B (part of the AQ25042B Control
Panel) for zoning with either line voltage
circulators or 24 Vac zone valves without end
switches.
AQ250 Control Panels can control a maximum of 16 zones
by connecting additional Expansion Zoning Panels to the
AQ250 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. To expand
the capacity of an AQ250 Control Panel beyond 16 zones,
an AQ254 Add-A-Temperature Expansion Control Panel is
required. The hydronic system can be expanded by 16
zones for each AQ254 connected to the AQ2000 network.
A maximum of three (3) AQ254 Panels may be connected
to an existing AQ2000 Control Panel for a maximum of 64
zones connected on the AQUATROL® network
NOTE: If an AQ254 Add-A-Temperature Expansion Con-
trol Panel is used for controlling the temperature
in a mixed loop, it can reset the mixed loop tem-

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 4
perature using LOAD reset, but not OUTDOOR
reset, as the AQ250 panel does not have input ter-
minals for an outdoor sensor.
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 two exceptions to this are:
1. AQ15740B Zoning Module for use with zone valves
with end switches.
2. AQ15540B Zoning Module when used with low volt-
age zone valves without end switches.
For these the two exceptions, 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. AQ250 Control Panel layout (AQ25044B shown).
Fig. 2. Internal wiring for AQ2000 Series components line voltage relays.
Zone 1 Zone 2 Zone 3 Zone 4
ZR Boiler DHW Aux
M29032A
LOW VOLTAG
(24 V)
LOW VOLTAG
(24 V)
ZONING MODULE
CONTROL MODULE
TRANSFORMER
LINE VOLTAGE
(120 V)
M29033
A
Zone 1 Zone 2 Zone 3 Zone 4
CONTACTS
SYMBOL
ZR Boiler DHW Aux

AQ250 SERIES HYDRONIC CONTROL PANELS
568-0306—07
2MOUNTING
This section describes how to mount the Control Panel,
Expansion Zoning Panels, and the Thermostats.
Mount AQ250 Control Panel
Mount the control panel on the wall:
1. Use the template supplied with the AQ250 Series
Control Panel to mark the four mounting holes for
the panel.
2. Install two top screws, mount the panel, and install
the two lower screws.
Mount Expansion Zoning Panels
If there are Expansion Zoning Panels to install, mount
them to the wall now:
1. Remove wire channel plugs from the AQ250 Control
Panel and any Expansion Zoning Panels (see
Fig. 3 on page 5).
2. Mount Expansion Zoning Panel on the right-hand
end of the AQ250 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 Con-
trol Panel and the Expansion Zoning Panel (see
Fig. 3 on page 5) and to connect the two panels
together.
4. For any additional Expansion Zoning Panels, repeat
steps 1–3
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 AQ250 Control Panel.
When using AQ1000 thermostats refer to the installation
instructions 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 AQ250 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.resideo.com or your local
distributor.
M23733A
WIRE
CHANNEL
PLUGS
WIRE
CHANNEL
PLUGS

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 6
3 WIRING PROCEDURE
The AQ250 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 secondary are wired to the R
and C input terminals of the Control Module, as well as the
R and C inputs of the Zoning Module. The B-B Exp. Bus
terminals (13 and 14) 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 on page 6 and moving
clockwise around the panel, wire components to the
AQ250 Control Panel and Expansion Zoning Panels (if
installed) in the following six steps:
• “Step 1 – Transformer Wiring” on page 6
• “Step 2 – Control Panel Wiring” on page 6
•“Step3–Thermostats Wiring” on page 8
• “Step 4 – Zoning Equipment Wiring” on page 8
•“Step 5 – Line Voltage System Outputs” on page 10
• “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.
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 AQ250):
• “Temperature Sensor Wiring”
• “System Demands Wiring” on page 7
• “Low Voltage Outputs Wiring” on page 7
• “Communication Bus Wiring” on page 7
Fig. 5. Low voltage wiring for the AQ1520M0 Control
Module.
Temperature Sensor Wiring
Connect the lead wires of each sensor to the
corresponding terminals on top of the AQ15000B Control
Module. See Fig. 5.
M29034
A
STEP 1 STEP 2 STEP 3
STEP 4
STEP 5STEP 6
TO EXPANSION ZONING MODULES
(IF INSTALLED)
ZR Boi l er DHW Aux.
ZR Boiler DHW Aux
TO BOILER SUPPLY SENSOR TO BOILER RETURN SENSOR
TO SETPOINT LOAD (OPTIONAL)
TO DHW AQUASTAT
IN FROM “R” TERMINAL ON TRANSFORMER MODULE (FACTORY-WIRED)
IN FROM “C” TERMINAL ON TRANSFORMER MODULE (FACTORY-WIRED)
TO “T-T” TERMINALS ON BOILER AQUASTAT
TO B-B “EXP.BUS IN” TERMINALS ON CONNECTED ZONING MODULE
M29035A

AQ250 SERIES HYDRONIC CONTROL PANELS
768-0306—07
The Boiler Supply and Return 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 AQ250 Control Panel. Even if the AQ250
is connected to a modulating condensing boiler with its
own supply and/or return sensors, the AQ250’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
AQ250. See Fig. 6 on page 7.
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 AQ250. 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.
Fig. 6. Strap-on 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 because the calculated
temperature - based on the sensor's resistance
reading - can be distorted by high EMI, potentially
causing the AQ250 to not operate properly.
If using shielded cable or conduit, connect the
shield wire to earth ground only at the AQ250
panel. Do not ground the shield or conduit at any
other location or electromagnetic shielding will be
ineffective. If shielded cable is used, Resideo
recommends the use of shielded cable with a
continuous ground plane, such as foil, with an
integral drain wire for bonding to earth ground.
System Demands Wiring
HEAT DEMAND
Wire the Heat Demand (terminals 7 and 8) to a system
setpoint demand (dry contact closure), such as a pool or
spa Aquastat®.
DOMESTIC HOT WATER (OPTIONAL)
If used, wire the DHW (terminals 9 and 10) 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 AQ250 is connected to a modulating con-
densing boiler with built-in DHW management,
the DHW tank’s Aquastat should be connected to
the AQ250's DHW (terminals 9 and 10). In this
case, the Aux Out contacts should be pro-
grammed (in Installer Mode settings) to close
when there's a call for DHW [EQUIPMENT
SETUP>AUXILIARY IO>AUX.OUT>
DHW]
Low Voltage Outputs Wiring
BOILER
Wire the Boiler dry contact output (terminals 11 and 12) to
the T-T terminals on the boiler Aquastat or the boiler's
control panel. See Fig. 14 on page 11 for wiring
connections to a typical boiler Aquastat.
It is not necessary to use the T-T terminals if connecting to
a Triple Aquastat, since the signal to the Aquastat is
received from the ZR/ZC terminals. See Fig. 14 and Fig. 15
beginning on page 11 for line voltage connection to boiler
Aquastats.
These contacts are made any time the system has a
request for boiler operation. When this occurs, the
system’s primary boiler pump comes on.
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) 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. 7 for how this wiring is to be installed.
M13763

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 8
The communication bus connections for AQ250 Control
Panels are pre-wired at the factory.
Fig. 7. Wiring for communication bus.
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. 8).
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 (termi-
nals 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 AQ250 to not operate properly.
3. Run low voltage thermostat wiring from the R and C
output terminals on the secondary of the AQ250
Control Panel’s transformer to the R and C input ter-
minals on the Expansion Zoning Panel. As an alter-
native, 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.
Fig. 8. Connecting thermostats.
Step 4 – Zoning Equipment Wiring
Because the Zoning Module of the AQ25042B Control
Panel can be used with either line voltage pumps or valves,
or low voltage zone valves (with or without end switches),
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. 9. Remove the plastic wiring barrier that is
located in the bottom wiring channel between the
AQ15000B Control Module and the Zoning Module. Run
jumper wires from the N and L terminals on the bottom of
the AQ250 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.
Zone 1 Zone 2 Zone 3 Zone 4
ZR Boiler DHW Aux
Zone 1 Zone 2 Zone 3 Zone 4
DATA BUS
COMMUNICATION
WIRING
M29036A
AQ25744B
AQ25042B
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

AQ250 SERIES HYDRONIC CONTROL PANELS
968-0306—07
Fig. 9. Wiring an AQ15540B Zoning Module for use
with line voltage circulators.
Low Voltage – Zone Valves With or
Without End Switches
IMPORTANT
If low voltage zone valves are used with the
AQ25042B Control Panel, the supplied Low
Voltage Output sticker (shown in Fig. 10) must be
applied over the line voltage output sticker (see
Fig. 9) that is already attached to the Zoning
Module.
Fig. 10. Low voltage output sticker.
WIRING ZONE VALVES WITHOUT END SWITCHES
— Using Fig. 11 on page 9 as a guide, run jumper
wires from the R and C terminals on the secondary
of the AQ250’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.
Fig. 11. Wiring an AQ15540B Zoning Module for use
with low voltage zone valves without end switches.
WIRING ZONE VALVES WITH END SWITCHES:
— See Fig. 12. 24 Vac power is pre-wired between the
transformer secondary at the top left of the
AQ250’s transformer and the AQ15740B Zoning
Module. No field wiring is required.
Fig. 12. Wiring an AQ15740B Zoning Module for use
with low voltage zone valves with end switches.
CAUTION
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.
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 sup-
plied with the AQ250 Control Panel. This integral
transformer has enough power to operate 4
motorized zone valves (such as V8043E valves or
4 valves using low-amperage draw, heat motor
actuators, such as MV100 actuators), plus power
the electronics of the AQ250's Control Module
and up to 16 AQ1000 thermostats. If zone valves
with high-amperage draw, 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. 13 on page 10 for recommended
wiring of additional low voltage VA capacity to
AQ2000 Series Zoning Modules.
FROM LINE VOLTAGE
120V TERMINALS
(N AND L) ON BOTTOM
OF TRANSFORMER M29037A
M27688A
FROM LOW VOLTAGE
24 VAC TERMINALS
(C AND R) ON TOP
OF TRANSFORMER
MMMM
M27689A
M
M27690A
MMM

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 10
Fig. 13. Wiring of additional low voltage VA capacity.
Step 5 – Line Voltage System
Outputs
See Fig. 14 and Fig. 15 on page 11 for wiring diagrams for
the line voltage outputs.
NOTE: It is not necessary to connect the boiler equip-
ment’s “T-T” terminals to the low voltage BOILER
dry contacts (Terminals 11-12) of the AQ250
when using a Triple Aquastat on the boiler. See
Fig. 15 on page 11.
Follow these steps to wire the devices to the AQ250
Control Module.
“1. Boiler Pump” on page 12
“2. DHW Aquastat Device” on page 12
“3. Line Voltage Rated Aux Output (optional)” on page 12
THERMOSTATS
ZONE 1 ZONE 2 ZONE 3 ZONE 4
M29038A
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

AQ250 SERIES HYDRONIC CONTROL PANELS
11 68-0306—07
Fig. 14. Line Voltage Connections for AQ250.
Fig. 15. Line Voltage Connections for AQ250 using triple function Aquastat.
TO BOILER
TERMINALS 11-12
ON TOP OF AQ15200B
CONTROL MODULE
ZC
ZR
B1
B2
C1C2
L1
L2
TT
G
L8124, L7224
R8184
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
2
1
DO NOT WIRE THE BOILER LOOP CIRCULATOR TO THE AQUASTAT'S C1/C2 TERMINALS; IT MUST BE CONNECTED TO THE BOILER PUMP TERMINALS
ON THE BOTTOM OF THE AQ15000B CONTROL MODULE WHEN MAINTAINING A MINIMUM BOILER TEMPERATURE (WITH A TRIPLE FUNCTION AQUASTAT).
2
BOILER
PUMP
M29039A
FROM LINE
VOLTAGE 120V
TERMINALS
(N AND L) ON
BOTTOM OF
TRANSFORMER
TO AUXILIARY DEVICE
(INSTALLER-DEFINED)
JUMPERED
AT FACTORY
ZC
ZR
B1
B2
C1
C2
L1
L2
T
T
G
L8124, L7224
R8184
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
FOR INSTALLATIONS USING A TRIPLE FUNCTION AQUASTAT, NOTE THAT THE FACTORY-INSTALLED JUMPER BETWEEN THE ZR AND ZC TERMINALS
MUST BE REMOVED. THE ZR AND ZC TERMINALS ON THE AQ15000B CONTROL MODULE MUST BE WIRED TO THE ZR AND ZC TERMINALS,
RESPECTIVELY, OF THE TRIPLE AQUASTAT.
2
TO AUXILIARY DEVICE
(INSTALLER-DEFINED)
BOILER
PUMP
M29040A
NL
TO LINE VOLTAGE 120V
TERMINALS (N AND L) ON
BOTTOM OF TRANSFORMER
TO BOILER TERMINALS
11 AND 12 ON TOP OF
AQ15000B CONTROL MODULE
2

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 12
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. The ground wire of the pump can
be connected to any of the 6 ground screw terminals
located on the back surface of the Control Panel
enclosure.
NOTE: If the AQ250 is connected to a modulating con-
densing boiler, the boiler pump may need to be
connected to the boiler, not the AQ250. Confirm
this with the boiler’s installation manual.
2. DHW Aquastat 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.
If using a low voltage zone valve, wire the primary of a
spud-mounted 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 AQ250 Control Panel.
The DHW contacts are made when the DHW inputs on
terminals 9 and 10 are shorted by the controlling
Aquastat. When DHW Priority 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, if the DHW demand is
still active in the system. This repeats until the DHW is
satisfied.
NOTE: If the AQ250 is connected to a modulating con-
densing boiler, the DHW pump will probably need
to be connected to the boiler, not the AQ250. Con-
firm this with the boiler’s installation manual.
3. Line Voltage Rated Aux Output
(optional)
To connect a line voltage auxiliary device to these
contacts, such as a boiler bypass pump, power the device
from the N and L terminals on the bottom of the Control
Module, running the hot (L) lead through the Aux. Pump
contacts. See Fig. 16 for details. The exact wiring
schematic will depend on what is connected to these dry
contacts.
NOTE: Use of this output is optional. The Aux. pump dry
contacts are line voltage-rated but unpowered. A
low voltage device can be connected to these
contacts, but the wire's insulation must meet
applicable codes for use in line voltage enclo-
sures.
Fig. 16. Wiring of the Aux. pump line voltage rated dry
contacts (example shown is a by-pass pump).
Fig. 17. Wiring for Boiler Pump, and DHW Device.
M29045A
BY-PASS PUMP
M29044A
1
2
DO NOT WIRE THE BOILER LOOP CIRCULATOR TO THE BOILER’S AQUASTAT TERMINALS C1/C2; IT MUST BE CONNECTED TO THE BOILER PUMP
TERMINALS ON THE BOTTOM OF THE AQ15000B CONTROL MODULE WHEN MAINTAINING A MINIMUM BOILER TEMPERATURE (WITH A TRIPLE
FUNCTION AQUASTAT).
FOR INSTALLATIONS USING A TRIPLE FUNCTION AQUASTAT, NOTE THAT THE FACTORY-INSTALLED JUMPER BETWEEN THE ZR AND ZC TERMINALS
OF THE AQ15000B CONTROL MODULE MUST BE REMOVED. THE ZR AND ZC TERMINALS ON THE AQ15000B CONTROL MODULE MUST BE WIRED TO
THE ZR AND ZC TERMINALS, RESPECTIVELY, OF THE TRIPLE AQUASTAT.
1
2
FROM LINE VOLTAGE
120V TERMINALS
(N AND L) ON BOTTOM
OF TRANSFORMER
TO AUXILIARY DEVICE
(INSTALLER-DEFINED)
JUMPERED
AT FACTORY

AQ250 SERIES HYDRONIC CONTROL PANELS
13 68-0306—07
Step 6 – Connection To Line Voltage
Power
Connect the N and L line voltage inputs of the primary on
the AQ250 transformer to the electrical distribution panel
and power up the Control. A service switch should be
installed on the hot (L) lead to the distribution panel.
If multiple Zoning Modules are connected to the AQ250
Control Panel, the line voltage wiring can either be run
directly from the N and L terminals on the primary of the
transformer to each Zoning Module (Fig. 18 on page 13),
or run in a daisy chain from the N and L terminals of one
AQ2000 module to the N and L terminals of the next
AQ2000 module (see Fig. 19 on page 13).
CAUTION
Electrical Shock or Equipment Damage Hazard.
Can shock individuals or short equipment
circuitry.
When line voltage is applied to the AQ250 Control
Panel and the front cover of the Panel is removed,
there is a risk of electrocution. Be careful to avoid
contact with the line voltage (N and L) terminals,
either with your fingers or with metal tools (such as
a screwdriver) when power is applied to the Control
Panel.
Fig. 18. Connections for multiple Zoning Panels - parallel wiring.
Fig. 19. Alternate Connections for multiple Zoning Panels - daisy chain wiring.
Zone 1 Zone 2 Zone 3 Zone 4
Zone 1 Zone 2 Zone 3 Zone 4 Zone 1 Zone 2 Zone 3 Zone 4
M29041A
Menu
Home
OK
Zone 1 Zone 2 Zone 3 Zone 4
Zone 1 Zone 2 Zone 3 Zone 4 Zone 1 Zone 2 Zone 3 Zone 4
M29042A
Menu
Home
OK

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 14
4 CONFIGURE THE CONTROL PANEL
DIP SWITCHES
Only two steps are required to set up the AQ250 Series
Control Panel:
1. Check the DIP switch settings for the Control
Module. (see “AQ250 Control Module DIP Switch
Settings” on page 14)
2. Check the DIP switch settings for each Zoning Mod-
ule. (see “Zoning Module DIP Switch Settings” on
page 15)
AQ250 Control Module DIP Switch
Location
Operation of the AQ250’s Control Module is set by the
positions of its DIP switches, which are located behind the
blank cover in the left most section of the Control Module
(beside the section labeled ZR). See Fig. 20 for location of
these DIP switches.
Zoning Module DIP Switch Location
The AQ15540B (pump Zoning Module) and AQ15740B
(valves with end switches Zoning Module) both have DIP
switches in 8-switch banks and are concealed behind
snap-on covers, as shown in Fig. 20.
Fig. 20. Location of concealed DIP switches for
AQ15000B Control Module and the AQ155/AQ157
Zoning Modules.
DIP Switch Configuration
AQ250 Control Module DIP Switch
Settings
AQ250 Control Panels come from the factory with pre-
defined settings for all DIP switches. These factory default
settings were chosen because they are commonly-used by
hydronics contractors across North America. That means
that most of the settings only need to be checked by the
installing contractor to make sure they’re suitable for the
installation.
Although for many installations, these factory default
values for the Control Module and the Zoning Module(s)
are suitable, Resideo recommends that they be reviewed,
and changed as necessary, to get optimal performance of
the hydronic system controlled by the AQ2000 Series
products.
A chart of the setting options for each DIP switch is
attached to the inside of the DIP switch cover. More
detailed explanations for these settings, including the pre-
set factory defaults for each DIP switch, is shown in
Table 2.
When you finish setting the DIP switches for the Control
Panel, replace the front cover of the AQ250 Control Panel.
NOTE: The snap-on DIP switch cover is designed so it
cannot be removed (exposing the DIP switches)
when the front cover of the AQ250 Control Panel
is in place.
M23731A
AQ15540B

AQ250 SERIES HYDRONIC CONTROL PANELS
15 68-0306—07
Table 2. AQ15000B Control Module DIP switch arrangement
Zoning Module DIP Switch Settings
A chart of the different settings for each DIP switch is
attached to the inside of each DIP switch cover.
Refer to Table 3 on page 16, and check all DIP switch
settings. If necessary, change the switch settings to suit
the desired operation of the hydronic installation.
NOTES:
1. To set DIP switches 1 through 4, which identify
the unique address of each zone on the
AQUATROL network):
Refer to the descriptions in Table 3 for the
correct DIP switch settings for the Pump or
Valve Zoning Module.
Unpredictable zone behavior may occur if
more than one Zoning Module has DIP
switches (1-4) set to the same address.
2. DIP Switch 5 enables or disables Zone
Synchronization:
• The factory setting disables Zone
Synchronization, which is an energy saving
feature of the AQ2000 panels. Zone
Synchronization coordinates zone demands to
start at the same time when the boiler cycle
begins. The AQ2000 functions as activating
valves. The valve logic induces a delay before
activating the boiler pump even when zone
pumps are used. When Zone Synchronization is
not selected, the zone demands are served
whenever they call for heat.
• The Zone Synchronization feature replaces the
pump/valve selection of previous AQ2000
versions.
3. 4. DIP Switch 8 functionality:
• The factory setting enables 1-stage per zone
thermostat. The zoning module operates as four
1-stage zones.
• When using a 2-stage thermostat, set DIP
switch 8 to 2-Stg. The 2-stage selection uses
TH1 and TH2 inputs for 2-stage thermostat
control. For the selected zone, TH1 is the first
stage input from the thermostat and TH2 is the
second stage input. Inputs TH3 and TH4
operate in same manner. The 2-stage selection
reduces the zoning module to a 2 zone module
from a 4 zone module.
• When using digital 2-stage thermostats (non
AQ1000 thermostats), the system set-up
process changes slightly. During system set-up,
create an artificial demand on the zoning
module by increasing the set point on the
thermostat. The artificial demand is required
during the PRI/SEC setup menu to select the
primary and secondary loop for each zone and
stage.
Review the settings of all DIP switches for each Zoning
Module connected to an AQ15000B, to ensure they are
correct before system start-up.
When you finish setting the DIP switches for all the Zoning
Modules, replace the cover of each Expansion Zoning
Panel.
NOTE: The snap-on DIP switch covers are designed so
they cannot be removed (exposing the DIP
switches) when the front cover of the AQ250 Con-
trol Panel is in place.
DIP Switch Switch Description Label and Factory Settings
DHW
1DHW Device: Pump or Valve
2DHW Priority: Off or Priority
3DHW Priority Override: Off or O/Ride (override)
4BOILER POST PURGE LOCATION: OFF = ZONES ONLY; PURGE = DHW
TANK FIRST, THEN ZONES
Aux. 5Aux output: Main = default; Group = group pump
6Aux output: Main = default; Bypass = boiler bypass pump
Mass 7Load Mass: Lo = Low mass (baseboard); Hi = High mass (radiant slab)
8Not used at this time
Test
Diagnostic
Test
Diagnostic
M29043
ON
1234567 8
M23719A
AQ15000B

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 16
Table 3. AQ15540B Zoning Module (Pump Zoning Module) DIP Switch Arrangement.
DIP
Switc
h Switch Description Label and Factory Settings
1
2
3
4
Zone Address: The positions of these 4 DIP switches define the unique address for
each zone on the AQUATROL network. For each group of 4 zones, there can be
only one DIP switch in the right hand (On) position.
The correct DIP switch settings for each zone module are:
•First Zone (1-4) Module: 1 = ON position; 2, 3, and 4 = OFF position
•Second Zone (5-8) Module: 2 = ON position; 1, 3, and 4 = OFF position
•Third Zone (9-12) Module: 3 = ON position; 1, 2, and 4 = OFF position
•Fourth Zone (13-16) Module: 4 = ON position; 1, 2, and 3 = OFF position
5•If set to SYNC, zone synchronization is enabled.
•If set to NOT, zone synchronization is disabled.
6•If zone valves are normally closed (N.C.), set the NC/NO DIP switch to the Off
position.
•If zone valves are normally open (N.O.), set the NC/NO DIP switch to the On
position.
7•If set to Group (ON position), the AUX Pump contacts on the Control Module
are switched when any of the zones on this Zoning Module are active.a
•If set to - (OFF position), the AUX Pump contacts are not affected by activity on
these zones.
aThe AQ15000B Boiler Control Module DIP switch #5 must be set to GROUP position and DIP switch #6 must be set to MAIN position.
8•If set to 2-Stg (ON position), then 2-stage operation is activated on thermostat
inputs. The zoning module operates as two 2-stage zones or 3 zones (one 2-
stage and two 1-stage).
•If set to 1-Stg (OFF position), then operates as four 1-stage zones.
M23720A
AQ15540B
Test
Diagnostic
Test
M34972
ON
12345678

AQ250 SERIES HYDRONIC CONTROL PANELS
17 68-0306—07
5 TEST AND CHECK OUT THE
INSTALLATION
Startup
IMPORTANT
Apply power to the AQ250 Control Panel only after
all of the AQ2000 SERIES components (Control
Panel, thermostats, sensors, Zoning
Modules/Panels) have been connected to the
other equipment in the hydronic heating system
(boiler, zone valves or pumps, DHW, Aquastat, etc.).
When powered, the AQ250 Control Panel begins its start-
up routine, establishing communication with all other
AQ2000 Series components on the AQUATROL network.
Auto Test
This section describes the Auto Test functions of the
Control Module and the Zoning Panel(s).
A) Auto Test– AQ15000B Control Module
Auto Test operation enables the installer to test the system
installation by sequentially activating all of the Control
Module's outputs for 15 seconds each. Each step of the
Auto Test routine may be paused or skipped by pressing
the Test button, which is located above the DIP switches
on the AQ15000B Control Module.
STATUS LEDS
Every status light (ZR, BOILER pump, AUXiliary pump,
DHW pump) will be turned on for 15 seconds when its
corresponding output is energized during Auto Test.
CONTROL MODULE DIAGNOSTIC LED
This LED, which is labeled Diagnostic and is located above
the DIP switches on the AQ15000B Control Module, is
used by the AQ250 to communicate diagnostic data to the
user:
• Constantly ON indicates that the unit is working
properly.
• Constant, fast blinking indicates that the unit is in the
Auto Test mode.
• Constant, slow blinking indicates that Auto Test mode
has been paused.
• Coded blinking is used to communicate an error code
to the user. Refer to the Troubleshooting section of
these instructions for an explanation of these codes.
NOTE: The Diagnostic LED is OFF when the AQ250 Con-
trol Panel is not powered.
If this is the first time the AQ250 has been started:
1. Remove the front cover of the AQ250 by loosening
the 4 captive slot-Phillips screws.
2. Remove the AQ15000B Control Module’s DIP switch
cover (refer to Figure Fig. 20 on page 14 for the DIP
switch cover location)
3. Check to make sure that the LED, labelled Diagnos-
tic, is steadily illuminated (no blinking).
4. To begin the Auto Test, press the Test button until
you feel a click. The AQ250 now begins the Auto Test
routine and the Diagnostic LED on the AQ15000B
Control Module blinks quickly.
5. Pressing the Test button at any time during the Auto
Test routine pauses the routine indefinitely. While
paused, the Diagnostic LED blinks slowly.
6. Pressing the Test button while the Auto Test routine
is paused advances the routine to the start of the
next step in the routine (testing the next output) and
the Auto Test routine resumes its test procedure.
7. When the Auto Test routine is completed, the Diag-
nostic LED returns to a constant ON status (no
blinking).
8. To test each of the zone outputs (pumps or valves)
individually, proceed to “B) Auto Test–
AQ155/AQ157 Zoning Modules” to run the Auto Test
feature for each AQ155 / AQ157 Zoning Module
attached to the AQ15000B Control Module.
SEQUENCE OF OPERATION—AQ15000B CONTROL
MODULE
1. When the Test button is pressed, ALL space heating
zones connected to the Control Module are ener-
gized and remain energized for the duration of the
Auto Test routine
2. At the same time, the Diagnostic LED on the
AQ15000B Control Module begins to blink quickly,
the ZR relay is energized for 15 seconds, then the
relay shuts off.
3. Next, the BOILER relay is energized for 15 seconds,
then shuts off.
4. Next, the AUX relay is energized for 15 seconds, then
shuts off.
5. Next, the DHW relay is energized for 15 seconds,
then shuts off.
6. Next, the Boiler T-T dry contacts are energized for 15
seconds, then re-opened.
7. Then the AQ15000B exits the Auto Test routine and
the Diagnostic LED on the Module returns to steady
illumination (no blinking).
B) Auto Test– AQ155/AQ157 Zoning
Modules
Auto Test operation for Zoning Modules enables the
installer to test all zones wired to the Zoning Module by
sequentially activating the equipment connected to each
zone output (pump or valve) for 15 seconds. Each step of
the Auto Test routine may be paused or skipped by
pressing the Test button.
ZONING MODULE DIAGNOSTIC LED
The LED, which is labeled Diagnostic and is located above
the DIP switches on the AQ155/AQ157 Zoning Modules, is
used for communicating diagnostic data to the Installer.
Refer to “Troubleshooting” on page 19 for a description of
the Diagnostic LED error codes (blinking rates).
NOTE: The Diagnostic LED is OFF when the
AQ155/AQ157 Zoning Module is not powered.
If this is the first time the AQ250 Control Panel has been
started:
1. With the front cover of the AQ250 Control Panel
removed and set aside, remove the AQ Zoning Mod-
ule DIP switch cover (refer to Figure Fig. 20 on
page 14 for the DIP switch cover location).
2. Check to make sure that the LED, labelled Diagnos-
tic, is steadily illuminated (no blinking).

AQ250 SERIES HYDRONIC CONTROL PANELS
68-0306—07 18
3. To begin the Auto Test, press the Test button until
you feel a click. The AQ155/AQ157 Zoning Module
now begins the Auto Test routine, and the Diagnostic
LED on the Zoning Module blinks quickly.
4. Pressing the Test button at any time during the Auto
Test routine pauses the routine indefinitely. While
paused, the Diagnostic LED blinks slowly.
5. Pressing the Test button while the Auto Test routine
is paused advances the routine to the start of the
next step in the routine (testing the next zoning out-
put) and the Auto Test routine resumes its test pro-
cedure.
6. When the Auto Test routine is completed, the Diag-
nostic LED returns to a constant ON status (no
blinking).
7. Replace the DIP switch cover on the Zoning Module.
8. For each AQ155/AQ157 Zoning Module connected
to the AQ250, repeat steps 1-7
SEQUENCE OF OPERATION—AQ155/AQ157 ZONING
MODULES
1. When the Auto Test button is pressed, Zone 1 of the
Zoning Module is energized and the Diagnostic LED
on the AQ155/AQ157 begins to blink quickly.
2. Zone 1 remains energized for 15 seconds, then
shuts off.
3. Next, each of the remaining zones is energized,
sequentially for 15 seconds, starting with Zone 2,
and then shuts off.
4. After Zone 4 has de-energizes, the AQ155/AQ157
exits the Auto Test routine and the Diagnostic LED
on the Module returns to steady illumination (no
blinking).
C) End Auto Test
If no errors are detected in the Control Module or Zoning
Module Auto Test routines, the AQ250 is now ready for
operation. If errors are detected, refer to “Troubleshooting”
on page 19.
Checkout
1. If present, turn down the DHW Aquastat to avoid
interfering with space heating control operation.
2. Turn up the setpoint of one of the AQ1000 zone ther-
mostats.
2.1 The zone valve or pump associated with that
zone turns on.
2.2 The Boiler and T-T relay outputs energize.
NOTE: When a setpoint is changed on an AQ1000
thermostat, the AQ250’s boiler short cycle
protection is disabled in favor of a faster
reaction for the user.
3. Turn down the setpoint of one of the AQ1000 zone
thermostats.
3.1 The zone valve or pump associated with that
zone should turn off.
3.2 The Boiler, and T-T relay outputs should de-
energize.
4. Repeat steps 2 and 3 for all zones to verify each zone
is operating correctly. Thermostats may be exercised
individually or all together to accelerate the check
out process.
5. Turn up the DHW Aquastat to simulate a call for hot
water.
5.1 If the DHW device is a pump, the DHW relay
output energizes immediately, and the Boiler
pump relay remains off.
5.2 If the DHW device is a valve, the Boiler pump
relay energizes after a 15 second delay to allow
the zone valve to fully open.
5.3 Turn up the set point of one of the AQ1000 zone
thermostats.
5.3.1 If the DHW relay is configured to control a
pump, and DHW Priority is selected, the
Boiler and associated zone pumps relays
remain off.
5.3.2 If the DHW relay is configured to control a
valve, and DHW Priority is selected, the
associated zone relays remain off.
5.3.3 If DHW Priority is disabled, space heating
(zone pumps and valves) operates
normally even during a call for DHW.
6. Turn down the DHW Aquastat to end the call for hot
water. Space heating operation should continue (if
DHW priority is disabled) or resume (if DHW PRIOrity
is enabled).

AQ250 SERIES HYDRONIC CONTROL PANELS
19 68-0306—07
6 PURGE AIR FROM ALL SYSTEM AND
ZONE PIPING
Purging air from all zones in the hydronic system is easily
accomplished with the AQ250 by using a modification to
the Auto Test feature (described in “Auto Test” on page 17)
as follows:
• To purge all zones on the AQUATROL network press the
Test button on the AQ15000B Control Module once to
begin the Auto Test routine. Quickly press it again 3
times until the Boiler relay LED illuminates and the
Diagnostic LED of the AQ15000B blinks slowly (which
indicates the Auto Test routine has been paused). The
boiler pump now remains energized for the duration of
the Purge routine (and therefore can be purging all
loops of air) until the Test button is pressed again.
• The Diagnostic LED blinks slowly while in paused
mode. Continue to purge the boiler loop as long as is
needed to remove air from the system.
• Leaving the boiler pump operating, push the Test
button on the Zoning Module for any space heating
zones you wish to purge.
• With the first zone's output energized (the
LED for Zone 1 illuminates), press the Test
button again to pause the Auto Test routine.
• When Zone 1 has been sufficiently purged,
press the Test button again to begin purging
Zone 2.
• Again, press the Test button to pause the Auto
Test routine while purging Zone 2.
• Continue to purge all other space heating
zones in the system.
If additional purging is required for any zone, the Auto Test
procedure can be activated for any individual Zoning
Module by pressing the Test button located above that
Zoning Module’s DIP switches. Refer to “B) Auto Test–
AQ155/AQ157 Zoning Modules” on page 17.
7 DOCUMENT AND KEEP A RECORD
OF ALL SYSTEM SETTINGS
After the AQ250 Series Control Panel and any
AQ255/AQ257 Expansion Zoning Panels have been set up
and the entire hydronic installation is operating properly,
it is important to document all the system settings for
future reference.
Job Records
All AQ2000 Series Panels are shipped with Installation Job
Recordsafor documenting these settings.These should be
filled out completely and saved in the Installing
Contractor’s files.
TROUBLESHOOTING
The following information helps the installer correctly
identify system problems, making troubleshooting much
faster. Table 4 and Table 5 on page 20 describe the
possible error codes that can be communicated on the
diagnostic LEDs of the AQ15000B Control Module and
AQ155/AQ157 Zoning Module.
Communications Loss
Because all AQ2000 Series components communicate
with each other via the dedicated AQUATROL network
when controlling a hydronic system, one possible failure
mode of the AQ250 would be loss of communication
between the AQ15000B Control Module and any
connected Zoning Modules, or between a Zoning Module
and any zone thermostats connected to the AQUATROL
network. In general, the Control Module:
• Periodically tries to re-establish communication with
any lost components on the network.
• Initializes any component that re-establishes its
communication.
CONTROL MODULE REACTION
When the AQ15000B Control Module loses
communication with any number of zones for more than
one minute (as long as there is still at least one zone
communicating on the AQUATROL network), the AQ250
continues to deliver heat to the other non-communicating
zones.
When communication is lost with all zones, the AQ250
enters Freeze Protection mode, in which it fires the boiler
and then activates the Boiler (supply) pump and zone
equipment for a period of 4 minutes every hour. This
should provide sufficient heat to the system to prevent a
building from freezing up until communication is re-
established between the AQ2000 Series components.
ZONING MODULE REACTION
When a Zoning Module loses communication with the
Control Module (as long as there is at least one other
Zoning Module communicating with the Control Module),
the Zoning Module operates its pumps or valves in a
conventional, non-synchronized zoning fashion. That is, it
operates according to the demands from the thermostats,
without zone synchronization or waiting for permission
from the AQ15000B Control Module to operate. This
allows the zones to extract any heat provided by the boiler.
When using AQ1000 thermostats and communication is
lost between a Zoning Module and one of its thermostats,
that zone is invisible to the Control Module, and the
Zoning Module stops serving that zone and the zone’s
pump or valve is de-energized.
The AQ250 provides Zoning Module diagnostic
information via the Diagnostic LED located above the DIP
switches on each Zoning Module.
aFor the AQ250 Series, refer to AQ25042B RelayPLUS
Zone Synchronizing Boiler Control, (form 69-1972) and
AQ25044B RelayPLUS Zone Synchronizing Boiler Con-
trol (form 69-2030)

AQ250 SERIES HYDRONIC CONTROL PANELS
© 2020 Resideo Technologies, Inc. All rights reserved.
The Honeywell Home trademark is used under license from Honeywell International, Inc. This product is manufactured by Resideo Technologies, Inc. and its affiliates.
www.resideo.com
Resideo Technologies, Inc.
1985 Douglas Drive North, Golden Valley, MN 55422
1-800-468-1502
68-0306—07 M.S. Rev. 05-20 | Printed in United States
AQUATROL® is a registered trademark of Resideo Technologies, Inc.
Aquastat® is a registered trademark of Resideo Technologies, Inc.
Table 4. AQ15000B Control Module LED Display and Error Codes.
Diagnostic Led Status System Condition Action Required
Steady (no blinking) No system problem detected None.
Fast blinking (4 blinks per second) Auto Test is in operation None. Permit the control to finish
Auto Test routine.
Slow blinking (2 blinks every 3 seconds) Auto Test has been paused Press the Test button to resume Auto
Test routine.
Coded blinking = ERROR 2 blinks then
pause
Freeze protection activated across
AQUATROL network
All zones have lost communication
with controller.
•Check B-B wiring between Control
Module and Zoning Module.
4 blinks then
pause
Return sensor open / short Check the return sensor wiring.
5 blinks then
pause
Supply sensor open / short Check the supply sensor wiring.
Table 5. AQ155/AQ157 Zoning Module LED Display and Error Codes.
Diagnostic Led Status System Condition Action Required
Steady (no blinking) No system problem detected None.
Fast blinking (4 blinks per second) Auto Test is in operation None. Permit the control to finish
Auto Test routine.
Slow blinking (2 blinks every 3 seconds) Auto Test has been paused Press the Test button to resume Auto
Test routine.
Coded blinking = ERROR •2 blinks then
pause
Freeze protection activated on the
Zoning Module
Zoning module has lost
communication with controller.
•Check B-B wiring between Control
Module and Zoning Module.
•3 blinks then
pause
Communication lost with ALL
thermostats
Check thermostat wiring to Zoning
Modules.