Daikin Trailblazer AGZ030E-070E Installation, Operation And Maintenance Manual page 87

T1 - Off to Auto
All of the following are required:
• Unit Enable = On
• No Unit Alarm active
• A circuit is enabled to start
• If Unit Mode = Ice then Ice Delay not active
• Low Ambient Lockout is not active
• Unit configuration settings are valid
T2 - Auto to Pumpdown
Any of the following are required:
• Unit Enable = Off and Unit Switch is closed
• Unit Mode = Ice AND LWT target is reached
• Unit Pumpdown Alarm active
• Low Ambient Lockout is active
T3 - Pumpdown to Off
Any of the following are required:
• Unit rapid stop alarm active
• All circuits complete pumpdown
• Unit Switch open
T4 - Auto to Off
Any of the following are required:
• Unit rapid stop alarm active
• No circuit enabled and no compressors running
• Unit Switch open
Motor Protection Module Power Up
Start Delay
After powering up the unit, the motor protection modules
may not be engaged for a period of time. Therefore, after
the control is powered up, no compressor can start for 150
seconds. In addition, the motor protect inputs are ignored
during this time so as to avoid tripping a false alarm.
Ice Mode Start Delay
An adjustable start to start ice delay timer will limit the
frequency with which the chiller may start in Ice mode. The
timer starts when the first compressor starts while the unit is in
ice mode. While this timer is active, the chiller cannot restart in
Ice mode. The time delay is adjustable via the Ice Time Delay
set point.
The ice delay timer may be manually cleared to force a restart
in ice mode. A set point specifically for clearing the ice mode
delay is available.
Low Ambient Lockout
The operation of the chiller in response to OAT dropping below
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the Low OAT Lockout set point is configurable if the chiller has
condenser fan VFD's. In that case, there are three options:
• Lockout and Stop – chiller will shut down and lockout
• Lockout only – chiller does not shut down running circuits,
will lock out circuits that are off
• Disabled – chiller does not shut down or lock out
For chillers without condenser fan VFD's, there is no
configuration and the chiller will always operate according to
the first option shown above. Descriptions of the operation for
each option are in the following sections.
Lockout and Stop Operation
When the chiller is configured for lockout and stop, it will
operate as described in this section.
If the OAT drops below the low ambient lockout set point and
the OAT sensor fault is not active, low ambient lockout is
triggered. The unit should go into the pumpdown state if any
circuits are running. If no circuits are running the unit should go
into the off state. This condition should clear when OAT rises to
the lockout set point plus 2.5°C (4.5°F).
Lockout Only Operation
When the chiller is configured for lockout only, it will operate as
described in this section.
If OAT drops below the low ambient lockout set point and
any circuits are running, then those circuits will be allowed
to remain running and the unit will not enter the low ambient
lockout condition. Circuits that are not running will enter a
circuit level lockout condition when OAT drops below the
lockout set point. This condition will clear at the circuit level
when OAT rises to the lockout set point plus 2.5°C (4.5°F).
If the OAT is below the low ambient lockout set point, the OAT
sensor fault is not active, and neither circuit is running, low
ambient lockout is triggered. The unit will go directly into the
off state and will remain in the off state until the lockout has
cleared. This condition will clear when OAT rises to the lockout
set point plus 2.5°C (4.5°F).
Disabled Operation
When the chiller is configured to disable low ambient lockout, it
will operate as described in this section.
Regardless of the OAT, the unit will not enter the low ambient
lockout condition or shut down any running circuits.
BAS Annunciation
Low Ambient Lockout is not an alarm, but it can be
annunciated to the BAS as if it is one. When the Low OAT
Lockout BAS Alert set point is set to On and the low ambient
lockout is active, the following will occur:
• Chiller alarm status parameter will show alarm state
• Active Problem Alarm Code will be set to 16642
(assuming no higher code is active)
• Active Problem Alarm Index will be set to 65 (assuming
no higher index is active)
87 IOM 1207-6 • TRAILBLAZER
Unit Functions
MODEL AGZ CHILLERS
®