Product manual

IOMM ACR/AGR-1 51
Table 22, Dip Switch Configuration
Remote Reset / Demand Limit
Global UNT Dipswitch Settings
Switch 1 2 3 4 5 6
On (10V) X X X X X
SW2
Off (2V) X
On (T) X
SW1
Off (V) X X X X X
UNT Controller Features
Remote Stop/Start
When the remote stop/start switch is open, the controller will be in the unoccupied mode. The unit
will be enabled when the remote start / stop switch is closed and will control at the leaving water
temperature setpoint.
Unoccupied Mode
When the remote start / stop input is opened, the unoccupied mode is initiated. The chiller will
maintain a higher leaving water temperature setpoint (default 70°F) if the chilled water circulation is
maintained. The unoccupied leaving water setpoint can be changed from the Zone Terminal.
Soft Start
Soft loading limits the number of available stages when the unit is started to prevent excessive power
consumption and possible overshoot of the leaving water temperature set point. Soft loading is in
effect whenever the unit is started from an “off” cycle. When stage up starts, the controller starts a
countdown timer to indicate how long the unit has been in the cool stage mode. The number of
stages allowed during soft loading is determined by the Soft Start Capacity. The duration of the soft
load sequence is determined by the Soft Start Timer. If the Soft Start Timer is set to zero, no soft
loading will take place. The Zone Terminal is required to change the Soft Start values.
Compressor Staging
The AGR Reciprocating chiller has two refrigerant circuits, each circuit has one reciprocating
compressors. When the first stage of cooling is required, the #1 compressor will start. This circuit will
be the first to start for the next ten unit starts. The Global UNT controller will then select the #2
compressor to start first for the next ten unit starts. This cycle will continue and balance the number
of starts between the refrigerant circuits. This is an automatic lead / lag control.
There are 4 to 6 stages of cooling capacity on the Global Reciprocating chiller unit. The first stage of
cooling will be the first compressor of the lead refrigerant circuit. The second stage of cooling will be
the first compressor of the lag refrigerant circuit. Cooling stages 3 through 6 are compressor by
unloaders.