Unit installation

IOMM ACZ/AGZ-3 ACZ / AGZ-BM 63
Control Logic
Unit Enable
Enabling and disabling the chiller is controlled by the Unit Enable Setpoint, with options of OFF
and ON. This setpoint can be altered by the Unit Off Input, Digital Input, keypad entry, or BAS
request. The Control Source setpoint determines which source can change the Unit Enable setpoint
with options of DIGITAL INPUT, KEYPAD, or BAS.
Changing the Unit Enable Setpoint can be accomplished according to the following table.
Table 44, Unit Enable Conditions
Unit Off
Input
Control Source
Setpoint
Remote Input Keypad Entry BAS Request Enable
OFF x x x x OFF
x SWITCHES OFF x x OFF
ON SWITCHES ON x x ON
ON KEYPAD X OFF x OFF
ON KEYPAD X ON x ON
ON NETWORK x x OFF OFF
On NETWORK OFF x x OFF
ON NETWORK ON x ON ON
NOTE: An “x” indicates that the value is ignored.
Unit Mode Selection
The overall operating mode of the chiller is set by the Unit Mode Setpoint with options of COOL,
COOL w/Glycol, ICE w/Glycol, and TEST. This mode setting can be altered by the keypad, BAS,
and Mode input. Changes to the Unit Mode Setpoint are controlled by two additional setpoints:
• Available Modes Setpoint: Determines the operational modes available at any time with options
of COOL, COOL w/Glycol, COOL/ICE w/Glycol, and TEST.
• Control Source Setpoint: Determines the source that can change the Unit Mode Setpoint with
options of DIGITAL INPUT, KEYPAD, or BAS.
When the Control source is set to KEYPAD, the Unit Mode stays at its previous setting until
changed by the operator. When the Control source is set to BAS, the most recent BAS mode request
goes into effect even if it changed while the Control source was set to KEYPAD or DIGITAL
INPUTS.
Changing the Unit Mode Setpoint can be accomplished according to the following table.
Table 45, Unit Mode Selection
Control Source
Setpoint
Mode
Input
Keypad Entry
BAS
Request
Available Modes
Setpoint
Unit Mode
x x x x COOL COOL
x x x x COOL w/Glycol COOL w/Glycol
SWITCHES OFF x x COOL/ICE w/Glycol COOL w/Glycol
SWITCHES ON x x COOL/ICE w/Glycol ICE w/Glycol
KEYPAD x COOL w/Glycol x COOL/ICE w/Glycol COOL w/Glycol
KEYPAD x ICE w/Glycol x COOL/ICE w/Glycol ICE w/Glycol
NETWORK x x COOL COOL/ICE w/Glycol COOL w/Glycol
NETWORK x x ICE COOL/ICE w/Glycol ICE w/Glycol
x x x x ICE w/Glycol ICE w/Glycol
x x x x TEST TEST
NOTE: An “x” indicates that the value is ignored.