Unit Mode Selection; Unit States - Daikin AGZ 025D Operating & Maintenance Manual

Unit Mode Selection

The operating mode of the unit is determined by
setpoints and inputs to the chiller. The Available
Modes Set Point determines what modes of
operation can be used.
determines whether the unit is configured for
glycol use. The Control Source Set Point
determines where a command to change modes
will come from. A digital input switches between
cool mode and ice mode if they are available and
the control source is set to 'local.' The BAS mode
Control Source
Set Point
Local
Local
Network
Network
Glycol Configuration
If the Available Modes Set Point is set to an option 'w/Glycol', then glycol operation should be enabled for
the unit. Glycol operation should only be disabled when the Available Modes Set Point is set to 'Cool'.

Unit States

The unit will always be in one of three states:
Off – Unit is not enabled to run
Auto – Unit is enabled to run
Pumpdown – Unit is doing a normal shutdown
Transitions between these states are shown in the following diagram.
Diagram explanation on following page.
22
This set point also
Mode BAS Available Modes
Input Request
Cool w/Glycol
Off Cool/Ice w/Glycol
On Cool/Ice w/Glycol
Cool Cool/Ice w/Glycol
Ice Cool/Ice w/Glycol
POWER
ON
PUMPDOWN
AGZ 025D through 190D
request switches between cool mode and ice mode
if they are both available and the control source is
set to 'network.'
The Available Modes Set Point should only be
changeable when the unit switch is off. This is to
avoid changing modes of operation inadvertently
while the chiller is running.
Unit Mode is set according to the following table:
Unit Mode
Set Point
Cool Cool
Cool
Cool
Cool
Ice w/Glycol
Test Test
OFF
AUTO
T 2
Ice
Ice
Ice
OMM 1166-1