York YCAL Series, Installation Operation & Maintenance

Page: 125 / 174

FORM 150.66-NM3
ISSUE DATE: 09/25/2020
125
JOHNSON CONTROLS
SECTION 7 - UNIT CONTROLS
7
Option 4 – Ambient Control Type
A M B I E N T C O N T R O L
S T A N D A R D
The low ambient cutout is adjustable from 25°F to 60°F
(-3.9°C to 15.6°C).
or
A M B I E N T C O N T R O L
L O
W A M B I E N T
The low ambient cutout is programmable down to 0°F
(-17.8°C). A low ambient kit MUST be installed for
this option to be chosen. If the kit is NOT installed,
and low ambient is selected, low pressure faults and
compressor damage may occur.
Option 5 – Local/Remote Control Type
L O C A L / R E M O T E M O D E L
L O C A L
When programmed for LOCAL, an ISN or RCC con-
trol can be used to monitor only. The micro panel will
operate on locally programmed values and ignore all
commands from remote devices, or through the RS-
485 inputs. The chiller will communicate and send data
to the remote monitoring devices.
or
L O C A L / R E M O T E M O D E
R E M O T E
This mode should be selected when an ISN or RCC
control is to be used to control the chiller. This mode
will allow the ISN to control the following items: Re-
mote Start/Stop, Cooling Setpoint, Load Limit, and
History Buffer Request. If the unit receives no valid
ISN transmission for 5 minutes, it will revert back to
the locally programmed values.
Option 6 – Unit Control Mode
C O N T R O L M O D E
R E T U R N L I Q U I D
Unit control is based on return chilled liquid temp.
Return Chilled Liquid Control can only be selected on
units that have 4 to 6 compressors (dual system units).
or
C O N T R O L M O D E
L E A V I N G L I Q U I D
Option 7 – Display Units
D I S P L A Y U N I T S
I M P E R I A L
This mode displays system operating values in Impe-
rial units of °F or psig.
or
D I S P L A Y U N I T S
S I
This mode displays system operating values in Scien-
tific International Units of °C or BARG.
Option 8 – Lead/Lag Type (two system units
only)
L E A D / L A G C O N T R O L
M A N U A L S Y S 1 L E A D
SYS 1 selected as lead compressor. SYS 1 lead option
MUST be chosen if Hot Gas Bypass is installed.
or
L E A D / L A G C O N T R O L
M A N U A L S Y S 2 L E A D
SYS 2 selected as lead compressor.
or
L E A D / L A G C O N T R O L
A U T O
M A T I C
Lead/lag between systems may be selected to help
equalize average run hours between systems on chill-
ers with 2 refrigerant systems. Auto lead/lag allows
automatic lead/lag of the two systems based on an av-
erage run hours of the compressors in each system. A
new lead/lag assignment is made whenever all com-
pressors shut down. The microprocessor will then as-
sign the “lead” to the system with the shortest average
run time.