Power Up Start Delay; Ice Mode Start Delay; Unit Status; Start Delays - Daikin McQuay AGZ-D Operating And Maintenance Manual

T1 - Off to Auto
All of the following are required:

Unit Enable = On

No Unit Alarm

A circuit is enabled to start

If Unit Mode = Ice then Ice Delay not active
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
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

Power Up Start Delay

After powering up the unit, the motor protectors
may not be engaged for up to 150 seconds.
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

Unit Status

The displayed unit status should be determined by the conditions in the following table:
Enum
0 Auto
1 Motor Prot Delay
2 Off:Ice Mode Timer
3 Off:OAT Lockout
4 Off:All Cir Disabled
5 Off:Unit Alarm
Continued next page.
OMM 1087
Status
Unit State = Off, Unit Mode = Ice, and Ice Delay = Active
AGZ 025D through 190D
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. In
addition, cycling the power to the controller
should clear the ice delay timer.
Conditions
Unit State = Auto
Unit State = Auto and MP start up delay is active
Unit State = Off and Low OAT Lockout is active
Unit State = Off and both circuits unavailable
Unit State = Off and Unit Alarm active
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