AQUATROL Zone Synchronizing
Boiler Reset Controls
AQ251
USER OPERATION AND MAINTENANCE
thermostats in the home can display the actual outdoor
temperature when an outdoor sensor is connected to the
AQ251 Control Panel.
WARNING
Only trained, experienced, licensed service
technicians should service this Control Panel. The
front cover of the AQ251 Control Panel should not
be removed, as this will expose the user to
potentially dangerous line voltage (120V)
electricity.
Congratulations!
The AQUATROL AQ251 installed on your heating system is
the most powerful, yet user-friendly hydronic heating control
system available on the market for residential and light
commercial installations.
APPLICATION
The AQ251 series of AQUATROL® Boiler Reset Controls
provides simplified, energy-efficient outdoor temperature
compensated control of single-temperature, residential
hydronic heating systems. The AQ251 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 and with reduced boiler
cycling.
This instruction sheet contains all the information you need to
program the comfort settings of the AQ251 and to customize
its operation for your home or business. For detailed
information on the operation of this control, please consult the
trained hydronic heating professional that installed the AQ251
control.
CONTENTS
LCD Display Panel Layout ................................................
System Status and Error Codes .......................................
3
6
AQ251 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.
When AQ1000 communicating thermostats are used with the
AQ251 Zoning Modules, they can use the same wiring as
existing thermostats. Night setback operation can be
programmed from the AQ251 panel. Thanks to the network
communication capability of the AQ251 controls, AQ1000
This AQUATROL AQ251 Control Panel was installed by a trained hydronic heating contractor.
To service this product, or for any questions relating to its installation, please contact:
Installing contractor: ________________________________________________________
Address: __________________________________________________________________
Phone: (_______) __________________________________________________________
69-1979-04
AQUATROL ZONE SYNCHRONIZING BOILER RESET CONTROLS
NOTES:
LCD Display Panel Layout
1.
When setting times for the setback schedule, you
must use the – or + button to change the time.
The OK button, when pressed, defaults the time
setting to “--:--” (midnight).
The LCD on the AQ251 Control Panel is used to:
—
Monitor system status and performance.
Select and/or modify control settings for the hydronic
system.
2.
—
—
Diagnose and troubleshoot system problems.
•
•
If the active menu item leads to a further sub-menu,
pressing the OK button displays the sub-menu options on
the LCD. Scroll through this sub-menu to position the
indicator arrow (←) beside the desired menu item to input
or modify. Choose one of the options provided or input the
desired value for the menu item. When satisfied, scroll to
another item and your selection will be saved.
The layout of the display is logical and simple to navigate. The
information displays so that you can see at a glance the
system’s operating temperatures, as well as the status of the
system equipment, such as a call for heat, DHW pump ON,
the layout and features of the LCD display panel and keypad.
To define or modify another item within the same menu,
scroll the up and down buttons ( or v) until the indicator
arrow (←) is beside the desired option. Use the – or +
buttons to set the value for that item.
^
LCD Display Navigation
This section describes how the keypad is used to navigate the
LCD display and menus.
•
•
To move back (up) one level within a menu, press the
Menu button.
•
The LCD displays up to three lines of text at a time. For
menus with more than three lines, use the up and down
To return to the Home Page display, press the Home
button.
buttons ( or v) to scroll through the menu options.
^
•
•
As the menu is scrolled up or down, the indicator arrow (←)
shows which menu item is active.
NOTE: The AQ251 automatically returns to the Home Page
display after 60 minutes of inactivity on the keypad.
If the active menu item is part of a list of predefined options
(e.g., Day of the Week) press the – or + button to scroll
through the available options until the preferred option is
displayed. The option is automatically saved when the
indicator arrow is scrolled away from the value being
edited.
HOME PAGE DISPLAY
The Home Page is the default view displayed on the AQ251
Control Panel's LCD screen.
There are two Home Page views - Simple and Detail.
•
If the active menu item requires you to define a value (e.g.,
a setpoint), use the – or + button to decrease or increase
the value until the desired value is displayed. The selection
will be saved when the indicator arrow is scrolled up or
down.
•
Simple view shows 3 lines of text and is a brief description
of the system operation.
•
Detail view includes the same 3 lines plus 10 lines of
additional information. Detail view is the factory default.
The choice of the Simple or Detail Home Page view is made
from the USER MENU > PREFERENCES/TIME menu option.
The Home Page display information for the Simple and Detail
views is illustrated in Fig. 2.
KEYPAD
LCD DISPLAY
HOME PAGE (SIMPLE)
WEDNESDAY
PROGRAM:
OUTDOOR:
9:30A
LEAVE
-5
Menu
HOME PAGE (DETAIL)
WEDNESDAY
PROGRAM:
OUTDOOR:
TARGET:
BOILER:
RETURN:
DHW:
9:30A
LEAVE ꢀ RETRN SLEEP WAKE OCC UNOCC
-5
Home
180 ꢀ WWSD --
180
160
100
31
ZONE COUNT:
M27749
Fig. 2. Home Page displays (Simple and Detail).
3
69-1979—04
AQUATROL ZONE SYNCHRONIZING BOILER RESET CONTROLS
—
—
The time display in 12 hour (e.g., 7:00 PM) or 24 hour
format (e.g., 19:00).
Programming Instructions
Program the AQ251 by using the keypad and LCD display to
select parameters from the User Menu. Refer to Fig. 1 on
page 2 for an illustration of the LCD screen and keypad.
Date and time of day – allows building owner to reset
day and time of day in the event of a power outage of
more than 4 hours (refer to Troubleshooting section).
The Home Page display view, Simple or Detail. The
factory default is Detail.
The LCD Backlight – illuminated permanently (ON) or
set to automatically turn off backlight after 1 hour
(AUTO).
—
—
provide a graphical layout of the AQ251’s User and
Installer menus.
When a new AQ2000 component is connected on the
AQUATROL network, it will be seamlessly integrated in the
system after a few seconds. If one or more components are
disconnected or stop providing data to the network, a
message will appear on the System Status display until the
fault is corrected.
POWER FAILURE
If a power disruption lasts for more than 4 hours, the message
PLS SET DAY/TIME displays and optionally, the AQ251's
backlight flashes repeatedly. This displayed message
continues until the DATE and TIME OF DAY are updated. See
“Power Disruption Greater Than 4 Hours” on page 6.
User Menu Overview
ZONE SETTINGS (REQUIRES AQ1000 THERMOSTATS)
Settings in this sub-menu define:
The User Menu is intended for use by the building owner to
choose the LCD display preferences, Zone Settings (including
setpoint temperatures and setback times for each zone), and
temperatures for the WAKE, LEAVE, RETRN (return), and
SLEEP programs.
—
The temperature setpoints (target temperatures) for
each zone in the heating system
—
The temperature setback for each zone in the heating
system. This is the desired temperature drop when the
heating system enters the setback program SLEEP or
LEAVE.
The Home Page and User Menu allow the building owner to:
•
•
View the status of the system.
Set up preferences for how the system information is
displayed.
—
—
The maximum and minimum setpoints that can be
entered by a user at a thermostat screen for each
zone.
•
•
Set target temperatures for each zone (requires AQ1000
thermostats).
Program times of the day when the system will set back the
temperatures for all zones (requires AQ1000 thermostats).
Whether each zone can be set independently by the
AQ251 (i.e., some zones can be locked while others
are unlocked) depending on whether or not the key-
board on a thermostat is locked. When locked, no
changes can be made to a zone’s setpoint tempera-
ture through the thermostat. Changes can still be
made through the Zone Settings menu on the AQ251
control panel.
NOTE: If there are any problems with the system’s opera-
tion, the AQ251 displays error codes on the System
Status display of the LCD panel. For details on these,
PROGRAM SETTINGS
TO ACCESS THE USER MENU:
Using the Program Settings sub-menu, the building owner can
define the time of day when the entire heating system will
change programs (e.g., from SLEEP to WAKE).
Press the Menu button on the keypad at any time to access
the User Menu.
User Menu Settings
The AQ251 has provision for four different schedule periods
per day. They are defined as WAKE, LEAVE, RETRN (return),
and SLEEP:
The User menu has five sub-menus.
•
•
•
•
•
“System Status”
“Preferences/Time”
“Zone Settings (requires AQ1000 thermostats)”
“Program Settings”
“Statistics” on page 5
WAKE:
LEAVE:
RETRN:
Period when you awaken and want your
home at a comfortable temperature.
Period when you are away from home and
want an energy-saving temperature.
Period when you return home and want
your home back to a comfortable
temperature.
To make changes to the parameter settings in the User Menu,
refer to “LCD Display Navigation” on page 3.
SLEEP:
Period when you are asleep and want an
energy-saving temperature.
SYSTEM STATUS
This is a detailed list of activities going on in the heating
system (e.g., call for heat, DHW disabled), and provide the
building owner with a quick snapshot of the heating system’s
operation, primarily for purposes of troubleshooting and
system diagnostics.
There are three modes of operation – Automatic, Occupied
and Unoccupied:
AUTO:
In AUTO mode, the AQ251 follows the
WAKE, LEAVE, RETRN, and SLEEP
programs.
PREFERENCES/TIME
The preferences that the building owner can change in this
sub-menu are:
OCC:
In OCC mode, the AQ251 holds the
temperature of OCCUPIED programs
(WAKE and RETURN). This might be used
if the occupancy pattern of the building
—
The temperature scale for the display (Fahrenheit or
Celsius) for both the AQ251 control’s LCD and the
zone thermostats.
69-1979—04
4
AQUATROL ZONE SYNCHRONIZING BOILER RESET CONTROLS
changes temporarily, requiring the
temperature to be at a comfort level 24
hours/day.
2. Programming all days at the same time:
•
Select EDIT ALL DAYS from the Program Settings
sub-menu.
UNOCC: In UNOCC mode, the AQ251 holds the
temperature of UNOCCUPIED programs
(LEAVE and SLEEP). This might be used if
the building will be unoccupied for an
extended period of time, such as a vacation
period.
•
A sub-menu displays where you can change the
WAKE program time for all days, the LEAVE
program time for all days, etc.
•
•
•
When all four programs have been set, select the
COPY TO ALL DAYS option. This displays the
prompt: COPY TO ALL DAYS - ARE YOU SURE?.
Select Yes by positioning the indicator arrow at YES
and press the OK button.
Next, the same list of days as EDIT DAILY
(described in step 1) displays, except that all days
now show the times for the WAKE, LEAVE, RETRN,
and SLEEP programs that you set in the EDIT ALL
DAYS menu.
If you do not want all days of the week to have the
same program schedule (e.g., weekdays different
than weekends), you can now scroll down and
change the program times for certain days by
positioning the indicator arrow beside the program
time to change and using the + or – button to
increase or decrease the scheduled program time.
There are two ways to set the schedule program times for
WAKE, LEAVE, RETRN, and SLEEP:
—
—
One day at a time
All days at the same time
1. One day at a time programming:
•
Select EDIT DAILY from the Program Settings sub-
menu.
•
A list of four program times per day displays,
showing the factory pre-set times for all programs:
MON WAKE
MON LEAVE
MON RETRN
MON SLEEP
TUE WAKE
TUE LEAVE
TUE RETRN
TUE SLEEP
…
6:00A
8:00A
4:30P
10:00P
6:00A
8:00A
4:30P
10:00P
When the program times have been set for all days, press the
Home button to leave the programming menus and return to
the Home Page display. All settings take effect immediately.
NOTES:
SAT WAKE
SAT LEAVE
SAT RETRN
SAT SLEEP
SUN WAKE
SUN LEAVE
SUN RETRN
SUN SLEEP
6:00A
--:--
--:--
10:00P
6:00A
--:--
--:--
10:00P
1.
2.
Schedule times are in 15-minute intervals.
To have the AQ251 ignore a program change
(and therefore keep the previous program's set-
point temperature), position the cursor beside the
period to be ignored and press the OK button.
The AQ251 will display “--:--” beside that program
and, when operating, will continue with the previ-
ous program's setpoint until the next program
change.
•
Any of the times can be changed by scrolling to that
line and pressing the + or – button until the desired
program time is displayed.
STATISTICS
This sub-menu provides information about system activity and
mix valve cycle counts. See Fig. 3 on page 8 for an illustration
of the statistical data that can be displayed.
5
69-1979—04
AQUATROL ZONE SYNCHRONIZING BOILER RESET CONTROLS
Upon restart, the AQ251 displays its clock settings as: YEAR
= 2008, MONTH = JAN, DATE = 1. The message PLS SET
DAY/TIME displays. This displayed message continues until
the DATE and TIME OF DAY are updated.
TROUBLESHOOTING
Power Disruption
The AQ251’s system and thermostat (zone settings)
parameters are stored in non-volatile memory and are
updated as they change.
NOTE: If the power failure parameter is set to Backlight
(USER MENU > PREFERENCES/TIME), the LCD
backlight flashes repeatedly, along with the mes-
sage.
When a power disruption or loss of power occurs, the system
configuration is retained in memory.
The AQ251 remains permanently in OCCUPIED (or Comfort)
mode until the DAY and TIME OF DAY are updated.
When power is restored, the AQ251 Control Panel enters
auto-detection mode, reads its previously-stored settings, and
initializes all AQUATROL network components according to
their saved parameters.
System Status and Error Codes
System status alerts and error messages display on the
System Status Page. These messages are shown in Table 2.
POWER DISRUPTION GREATER THAN 4 HOURS
If a power disruption lasts for more than 4 hours, the AQ251
will have discharged its internal super capacitor, and the
DATE and TIME OF DAY settings will need to be reset.
Table 2. LCD Status Notices and Error Messages.
LCD Display
A/C MIN. OFF TIME
A/C MIN. ON TIME
AUX IN EM. SHUT
BOILER:
Parameter
n/a
Meaning
The A/C compressor is disabled, because the minimum OFF time has not yet elapsed.
The A/C compressor is active and the minimum ON time has not yet elapsed.
Auxiliary Input's Emergency Shut Down is active.
n/a
n/a
EM SHUT
FRZ PROT
Boiler is disabled, because the AQ251 is in Emergency Shut Down mode.
Boiler freeze protection activated:
•
Communication between Control Module and Zoning Module has been lost for more
than 1 minute
or
•
Boiler supply temperature is less than 50°F (10°C)
HEAT DHW Boiler is active to serve DHW.
HEATING
IDLE
Boiler is active to serve zones.
Boiler is not active.
INIT
Boiler contacts (terminals 22 and 23) on the AQ1520, which are connected to the
boiler's T-T terminals, have been shorted and the boiler is beginning its firing sequence.
INST PURG Boiler is active while the AQ251 is conducting the PURGE operation in the Installer
Setup.
NSTALL
Boiler is in ready mode during Installer Setup.
PMP EXER
Boiler is disabled while the AQ251 is exercising all pumps and valves connected to the
AQUATROL network.
POST PURG Boiler is active with Post Purge operation and is sending the purged water to the Boiler
(Primary) loop.
PURGE DHW Boiler is active with Post Purge operation and is sending the purged water to the DHW
tank.
CALL FOR COOL
CALL FOR DHW
CALL FOR HEAT
CWSD ACTIVE
n/a
n/a
n/a
n/a
At least one zone with a programmable thermostat requires cooling.
The DHW requires heat.
At least one zone requires heat.
Zone calls for cooling are not served because CWSD (Cold Weather Shutdown) is in
progress.
DHW DISABLE
n/a
n/a
DHW call is not served because it is disabled.
LOST ZONE A-1
…
Lost communication with a zone (A-1 to A-16, B-1 to B-16, C-1 to C-16, or D-1 to D-16).
LOST ZONE D-16
NO DHW PROBE
n/a
n/a
No DHW sensor connected or it is defective.
No outdoor sensor connected or it is defective.
NO OUTDOOR PROBE
69-1979—04
6
AQUATROL ZONE SYNCHRONIZING BOILER RESET CONTROLS
Table 2. LCD Status Notices and Error Messages. (Continued)
LCD Display
Parameter
Meaning
No return sensor connected or it is defective.
NO RETURN PROBE
NO SUPPLY PROBE
SHORT CYCLE PROT
n/a
n/a
n/a
No supply sensor connected or it is defective.
There is a call for heat, but less than two minutes have elapsed since the last firing of
the boiler (prevents short cycling).
VALVE INIT
n/a
n/a
n/a
Motorized mixing valve controlling the secondary loop is being initialized and
repositioned (opening or closing) to meet the secondary loop target temperature.
WATER READY
WWSD ACTIVE
Boiler Supply Water temperature is at or above the target temperature calculated by the
AQ251.
Zone calls for heat is not served because WWSD (Warm Weather Shutdown) is in
progress.
When an AQ thermostat is disconnected from the AQUATROL
network, a message displays on the System Status page of
the AQ251 indicating “Lost Zone A-xx”, where “xx” is the
specific identity, or address, of the lost zone. This helps the
servicing contractor quickly identify the lost zone and fix its
wiring, to re-establish communication with the Control Module.
When a new AQ2000 component is connected on the
AQUATROL network, its settings are communicated to the
AQ251's Boiler Control Module (AQ1520M0) within 10
seconds of being connected. If the component is an AQ1000
thermostat, the setpoints for that zone thermostat can be
modified from the Boiler Control Module as soon as it is
recognized by the Control Module.
7
69-1979—04
AQUATROL ZONE SYNCHRONIZING BOILER RESET CONTROLS
USER MENU STRUCTURE
Press the Menu button on the keypad to display the User Menu. Fig. 3 illustrates all possible User Menu selections.
USER MENU
SYSTEM STATUS
PREFERENCES/TIME
ZONE SETTINGS
PROGRAM SETTINGS
STATISTICS
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
1
SYSTEM STATUS
PREFERENCES / TIME
ZONE SETTINGS (All or Single)
PROGRAM SETTINGS
STATISTICS
AUX IN EM.SHUT
LAST DATA RESET: 2000 JAN 01
MODE:
AUTOꢁ
BOILER UNITS:
ZONE UNITS:
TIME DISP:
°Fꢁ
°Fꢁ
EDIT ALL ZONES
ꢁ
ꢁ
BOILER:
IDLEꢁ
BOILER FIRE ACTIV:
BOILER PUMP ACTIV:
DHW PUMP ACTIV:
AUX PUMP ACTIV:
AUX OUT ACTIV:
ZONE
0H
0H
EDIT ALL DAYS
EDIT DAILY
ꢁ
ꢁ
EDIT SINGLE ZONE
CALL FOR DHW
CALL FOR HEAT
DHW DISABLE
12Hꢁ
0H
D.S.T.:
YEAR:
ENABLEꢁ
2008ꢁ
JANꢁ
ARE YOU SURE?
NO YES
0H
LOST ZONE A-1
...
0H
MONTH:
A-1ꢁ
0H
DATE:
1ꢁ
LOST ZONE D-16
NO DHW PROBE
ACTIV:
DAY:
MONDAYꢁ
12:00Aꢁ
DETAILꢁ
AUTOꢁ
ZONE
A-1ꢁ
TIME:
ROOM TEMP
NO OUTDOOR PROBE
NO RETURN PROBE
NO SUPPLY PROBE
SHORT CYCLE PROT
VALVE INIT
HOMEPAGE:
BACKLIGHT:
POWER FAILURE
FLOOR TEMP
SETPOINT:
2
3
70ꢁ
EDIT ALL DAYS
FLOOR SETPT:
HEAT/COOL STATUS
SETBACK:
70ꢁ
NOTICE:
BACKLIGHTꢁ
ALL WAKE
ALL LEAVE
ALL RETRN
ALL SLEEP
6:00Aꢁ
8:00Aꢁ
4:30Pꢁ
10:00Pꢁ
7ꢁ
100ꢁ
41ꢁ
WATER READY
SETPOINT MAX:
SETPOINT MIN:
FLOOR LIM HI:
FLOOR LIM LO:
SETPOINT VACANCY
HEAT:
WWSD ACTIVE
ARE YOU SURE?
NO YES
COPY TO ALL DAYS
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
100ꢁ
41ꢁ
COPY WAKE
COPY LEAVE
COPY RETRN
COPY SLEEP
41ꢁ
SETPOINT VACANCY
COOL:
100ꢁ
CHANGEOVER:
2ꢁ
EDIT DAILY
KEYBOARD:
UNLOCKꢁ
MON WAKE
MON LEAVE
MON RETRN
MON SLEEP
...
6:00Aꢁ
8:00Aꢁ
4:30Pꢁ
10:00Pꢁ
1
2
4
5
THE ꢁ SYMBOLS INDICATE ADDITIONAL SELECTIONS ARE POSSIBLE.
THE FACTORY DEFAULT VALUES ARE SHOWN.
TEMPERATURE VALUES ARE SHOWN IN DEGREES FAHRENHEIT,
WHICH IS THE FACTORY DEFAULT TEMPERATURE UNIT.
SUN WAKE
SUN LEAVE
SUN RETRN
SUN SLEEP
6:00Aꢁ
--:--
--:--
ꢁ
ꢁ
10:00Pꢁ
3
4
5
EITHER HEAT OR COOL DISPLAYS DEPENDING ON THE SYSTEM’S STATUS.
FACTORY DEFAULT TIMES FOR MON THROUGH FRI.
FACTORY DEFAULT TIMES FOR SAT AND SUN.
M27750
Fig. 3. User Menu Structure.
AQUATROL® is a registered trademark of Honeywell International Inc.
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com
Honeywell Limited-Honeywell Limitée
35 Dynamic Drive
Toronto, Ontario M1V 4Z9
® U.S. Registered Trademark
© 2009 Honeywell International Inc.
69-1979—04 M.S. Rev. 09-09
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