Honeywell AQ25A Series Technical Reference Booklet page 27

Single Zone Freeze Protection mode is disabled when the
outdoor temperature is above the warm weather shutdown
(WWSD) temperature setting.
The AQ25A provides Zoning Module diagnostic information via
the DIAGNOSTIC LEDs located above the DIP switches on its
Zoning Module(s), as well as on the System Status menu of the
LCD display.
If a zone becomes disconnected from the Control Module or is
malfunctioning (i.e., lost), this can be seen in the ZONE
COUNT value on the AQ25A's Home Page display (Detail view
only). The ZONE COUNT represents the number of zones on
the AQUATROL network at any given time. When a zone is
lost, the ZONE COUNT decreases by one. Because an
installer knows how many zones are installed, if there is a
difference between the actual number of installed zones and
the ZONE COUNT, the installer will know to look for the
zone(s).
The identity of lost zones displays in the System Status page
as LOST ZONE A-X:
• A identifies the Control Module of the lost zone, and B, C, or
D identify an AQ25400B Add-A-Temperature Expansion
Control Panel. This prefix can be set or changed on the
AQ254 Panels.
• X identifies the lost zone (1 through 16).
Boiler Freeze Protection
related)
If the boiler supply temperature sensor measures 50°F (10°F)
or less, the boiler fires and the boiler pump, secondary pump
etc. operate until the target temperature is achieved, as
Table 3. AQ155 / AQ157 Zoning Module LED Display and System Condition.
DIAGNOSTIC LED Status
Steady (no blinking)
Fast blinking (4 blinks per second)
Slow blinking (2 blinks every 3 seconds)
Coded blinking = ERROR 2 blinks,
LCD Display
AUX IN EM. SHUT
BOILER: EM SHUT
FRZ PROT
HEAT DHW
(not network communication
No system problem detected
Auto Test is in operation
Auto Test has been paused.
Freeze protection activated
then pause across the entire AQUATROL
network
3 blinks, Communication lost with all
then pause thermostats on the Zoning
Module
Table 4. LCD Status Notices and Error Messages.
Parameter
n/a Auxiliary Input's Emergency Shut Down is active.
Boiler is disabled, because the AQ25A 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)
Boiler is active to serve DHW.
AQ25A SERIES PROGRAMMABLE BOILER CONTROL PANELS
measured by the supply temperature sensor. This target
temperature is the reset temp (if the boiler RESET parameter =
OUTDOOR). Or it is the AQ25A's BOILER HIGH LIMIT (if the
boiler RESET parameter = LOAD or NONE). DHW and Heat
Demand calls are ignored when the system is in freeze
protection mode.
Power Disruption
The AQ25A's system and thermostat parameters are stored in
non-volatile memory and are updated as they are changed.
When a power disruption occurs, the system configuration is
retained in memory. When power is restored, the AQ25A
Control Panel enters auto-detection mode, reads its
previously-stored settings, and initializes all AQUATROL
network components according to their saved parameters.
Power Disruption Greater Than 2 Hours
If a power disruption lasts for more than 2 hours, the AQ25A
will have discharged its internal super capacitor, and the DATE
and TIME OF DAY settings will need to be reset.
Upon restart, the AQ25A displays its clock settings as: YEAR =
2008, MONTH = JAN, DATE = 1. The message PLS SET DAY/
TIME displays and optionally, the AQ25A's backlight flashes
repeatedly. This displayed message continues until the DATE
and TIME OF DAY are updated. The AQ25A remains
permanently in OCCUPIED (or Comfort) mode until the DATE
and TIME OF DAY are updated.
System Condition
Meaning
21
Action Required
None
None. Allow the control to finish its Auto Test
routine.
Press the Test button to resume the Auto Test
routine.
All zones have lost communication with the
Control Module. Check B–B wiring between the
Control Module and each Zoning Module.
Check thermostat wiring to each Zoning
Module.
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