Honeywell AQ252 Catalog Page

AQUATROL Zoning System

AQ252 Universal Injection/Mixing Boiler Reset Control Panel for
Hydronic Zoning System

• Displays of outdoor temperature on all AQ1000 thermostats when
used with an AQ12C10 outdoor sensor (included).

• Intuitive programming interface and armchair programming (can be
programmed at your desk and taken to the job site “ready-to-install”)

• Customizable control settings and schedules allow for greater level
of control and comfort.

• Central programming of set points and setback.

• Controls up to 2 stages of heat from a single thermostat.

• Zoning Control for up to four 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 AQ254 Add-a-Temperature expansion

The AQ252 family of AQUATROL Universal Injection/Mixing Boiler
Reset Controls provides simplified, energy-efficient outdoor
temperature compensated control of single-temperature,
residential hydronic heating systems. The AQ252 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 with outdoor reset for
increased energy efficiency with reduced boiler cycling. AQ252
boiler controls can ensure ample supply of hot water for both
space heating and priority generation of domestic hot water for
bathing, dishes and laundry.

• Use with AQ1000 2-wire communicating thermostats or most digital
dry contact thermostats.

• Controls one boiler loop and one mixed temperature loop.

• Use of variable speed injection pump or motorized mixing valve for
mixed temperature loop control.

• 0-10 Vdc modulating output for driving a modulating/condensing
boiler or a modulating mixing valve.

Application: Controls one boiler and one mixing (either variable speed

injection or floating valve mixing) loop in a hydronic zoning system.

Dimensions, Approximate: 16 1/2 in wide x 8 in. high x 3 3/8 in deep

(42 cm wide x 20.3 cm high x 8.5 cm deep)

Powe r Su pply: 120V/60Hz
User Interface (Setting, Programming): (LCD Display and a 7 button

Key Pad)

Electrical Connections (Line Voltage): Wire-clamp screw terminals,

Maximum 2 x 14 AWG each on line voltage terminals

Control and Zoning Panel Temperature Rating: 32 F to 130 F

(0 C to 55 C)

Thermostat Compatibility: AQ1000 Series 2-wire communicating

thermostats and most digital thermostats

Zone Module Thermostat input: Low voltage, Class II, 2-wire polarity-

insensitive, digital communicating with power link to AQ1000 series
thermostat.

Setback Program: 7 day, up to 2 setback periods/day.
Boiler Design Temperature: 80F to 210F (26C to 99C)
Boiler (Supply) Min. Control Temperature: OFF, 59F to 180F (OFF,

15C to 82C)

Boiler (Supply) Max. Control Temperature: OFF, 120F to 225 F

(OFF, 49C to 107 C)

Boiler Heat Post Purge: Off, 10 seconds to 30 minutes (factory default

is 30 seconds)

Boiler (T-T) Output Rating: 24 Vac, 0.5A, 12VA
Boiler Differential: 2F to 41F (1C to 23C), or Auto (minimum 2 minutes

on time)

DHW Pump/Valve Output Rating: 120 Vac 5A, 1/3HP
DHW Demand Input: External dry contacts connection only
Outdoor Low Design Control Temperature:
Return Minimum Control Temperature: 80 F to 180 F (27C to 82C)
Variable Speed Injection Pump Output: Triac modulated; 120 Vac,

2.1A, 1/6HP

Pump/Valve exercise: 30 seconds per 2 weeks of space heating

inactivity

Secondary Pump Output Rating: 120 Vac 5A, 1/3HP

-60F to 32F (-51 C to 0 C)

panels.

• Outdoor temperature compensation (reset), or Load reset based on
indoor temperature feedback.

• Zone synchronization through Zone of Greatest Demand control.

• Domestic hot water priority and priority override protection.

• Line or low-voltage output for zoning equipment (pumps or valves).

• Boiler short cycling protection.

• Boiler post purge.

• Freeze protection.

• Pump/valve exercise.

• Boiler shock prevention from cold water returning to boiler.

• Automated test and purge feature for quick start-up and simplified
troubleshooting.

• Integral 38 VA transformer with self resetting electronic fuse.

• 4 hours power supply (super capacitor) to retain day and time
settings during power outage.

• Non-volatile EPROM memory retains program settings during power
outage.

Auxiliary Pump Output Rating: Dry contact output, 120 Vac/250 Vac

5A, 1/3 HP

Auxiliary Low Voltage Output Rating: 24 Vac, 0.5A, 12VA
Auxiliary (Demand) Input: External dry contacts connection only
Mixing Valve Floating Output (Com,O,C): 24Vac rated dry contacts
Mixing Valve Modulating Output: 0-10 Vdc
WWSD (Warm Weather Shut Down) Temperature: Off, 35 F to 100 F

(Off, 1 C to 38 C)
Zone Output Contact Rating: Pumps: 120 Vac/250 Vac, 5A, 1/3 HP
Valves: 24 Vac, 0.5 A, 12 VA

Sensor Temperature Rating: -58 F to +230 F (-50 C to +110 C)
Supply/Return Sensor: Lead Length: 10 ft. (3050 mm). 10 kilohm NTC

thermistor at 25 C (77 F) ±0.5F (±0.3C) up to 500 ft (150 M) using 18

AWG or larger wire
Heat Demand (Thermostat R-W) Input: External dry contacts

connection only
Secondary Loop Mixing (Supply) Design Temp Range: 70 F to 210

F (21 C to 99 C)

Secondary Loop Mixing (Supply) Max Control Temp Range:

80 F to 210 F (27 C to 99 C)
Secondary Loop Return Min Control Temp Range: 80 F to 180 F

(27 C to 82 C)
Secondary Loop Mixing (Supply) Min Control Temp Range: 3

5 F to 150 F (2 C to 66 C)
B-B Communication Bus Terminals: Low voltage, Class II, 2-wire

polarity-insensitive, digital communicating link to other Control or

Zoning modules.
R-C Input (on Control and Zoning Modules): 24 Vac Class II (input

on Control and Zoning Modules)

R-C Output (on transformer): 38 VA, 24 Vac Class II
Operating Humidity Range (% RH): 5 to 90% RH, non-condensing
Weight: 6.0 lbs (2.7 kg)

Approvals
Canadian Standards Association: CSA C/US Certified to CSA and

UL Standards, File No. LR76030

188 customer.honeywell.com 70-6910

AQUATROL Zoning System

Product Number

* AQ25242B/U Zone pumps or 2-wire

* AQ25244B/U Zone valves with end

* TRADELINE models • SUPER TRADELINE models

Type of Zoning
Devices Controlled

valves (line voltage)

switches

Number of Zones
Controlled

4 120 Vac/250 Vac 5A,

4 120 Vac/250 Vac 5A,

Boiler Pump
Output Rating Replacement Parts

1/3HP

1/3HP

AQ15200B universal injection/mixing boiler reset module;
AQ12C11 supply/return/mixed loop sensor;
AQ12C10 outdoor sensor; AQ10X38 24 Vac 38 VA transformer;
AQ15540B 4-zone pump expansion module

AQ15200B universal injection/mixing boiler reset module;
AQ15740B 4-zone valve with end switch expansion module;
AQ12C11 supply/return/mixed loop sensor; AQ12C10 outdoor sensor;
AQ10X38 24 Vac 38 VA transformer

AQ254 Add-a-Temperature Injection/Mixing Expansion Control Panel
for Hydronic Zoning System

expands the total network capacity by up to 16 zones when used
with AQ255 and/or AQ257 zoning panels.

• Acts as an add-on Control panel to the Main (AQ250, AQ25A,
AQ251, AQ252) Control panel.

• Allows each of the 16 zones connected to it to be assigned to the
system's primary or secondary loop.

• Up to 3 AQ254 panels can be added to a Main (AQ250, AQ25A,
AQ251 or AQ252) Control panel.

• Mixed loop temperature is controlled by a variable speed injection
pump or motorized mixing valve connected to the AQ254.

• Intuitive programming interface and armchair programming (can be
programmed at your desk and taken to the job site “ready-to-install”)

• Customizable mixing control settings allow for greater level of control

The AQ254 Add-a-Temperature Expansion Control Panel is used in
conjunction with an AQ250, AQ25A, AQ251 or AQ252 Control
Panel. It provides one additional loop temperature control
capability for the AQ2000 control panel it is connected to and

Application: Expanded zone control and mixed loop temperature

control in a hydronic zoning system
Mixed loop target temperature is reset by either outdoor temperature
or calculated system load based on indoor temperature feedback
Mixing is target controlled by a variable speed injection pump or
motorized mixing valve

Dimensions, Approximate: 9 1/2 in wide x 8 in. high x 3 3/8 in. deep

(24 cm wide x 20.3 cm high x 8.5 cm deep)

Powe r Su pply: 120V/60Hz
User Interface (Setting, Programming): (LCD Display and a 3 button

Key Pad)

Electrical Connections (Line Voltage): Wire-clamp screw terminals,

Maximum 2 x 14 AWG each on line voltage terminals

Control and Zoning Panel Temperature Rating: 32 F to 130 F (0 C to

55 C)

Thermostat Compatibility: AQ1000 Series 2-wire communicating

thermostats and most digital thermostats

Variable Speed Injection Pump Output: Triac modulated; 120 Vac,

2.1A, 1/6HP

Secondary Pump Output Rating: 120 Vac 5A, 1/3HP
Auxiliary Pump Output Rating: Dry contact output, 120 Vac/250 Vac

5A, 1/3 HP

and comfort.

• Zone synchronization through Zone of Greatest Demand control.

• Integral 38 VA transformer with self resetting electronic fuse.

Sensor Temperature Rating: -58 F to +230 F (-50 C to +110 C)
Secondary Loop Mixing (Supply) Design Temp Range: 70 F to 210

F (21 C to 99 C)

Secondary Loop Mixing (Supply) Max Control Temp Range: 80 F to

210 F (27 C to 99 C)

Secondary Loop Return Min Control Temp Range: 80 F to 180 F (27

C to 82 C)

Secondary Loop Mixing (Supply) Min Control Temp Range: 35 F to

150 F (2 C to 66 C)

B-B Communication Bus Terminals: Low voltage, Class II, 2-wire

polarity-insensitive, digital communicating link to other Control or
Zoning modules.

R-C Input (on Control and Zoning Modules): 24 Vac Class II (input

on Control and Zoning Modules)

R-C Output (on transformer): 38 VA, 24 Vac Class II
Operating Humidity Range (% RH): 5 to 90% RH, non-condensing
Weight: 3.9 lbs (1.8 kg)
Approvals
Canadian Standards Association: CSA C/US Certified to CSA and

UL Standards, File No. LR76030

Controls

Hydronic

Product Number Mixing Valve Floating Output (Com,O,C) Replacement Parts

* AQ25400B 24Vac rated dry contacts AQ15400B Add-A-Temperature expansion control module;

* TRADELINE models • SUPER TRADELINE models

70-6910 189

AQ12C11 supply/return/mixed loop sensor;
AQ10X38 24 Vac 38 VA transformer