Johnson Controls YORK YCAL0043E Series, Installation Operation & Maintenance

Page: 88 / 188

JOHNSON CONTROLS
88
FORM 150.62-NM9 (709)
UNIT CONTROLS
Option 4 – Ambient Control Type:
(YCAL0043-0253 Only)
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. YCAL0287-0377
are fixed in the low ambient mode as standard and
cannot be reprogrammed.
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 control
can be used to monitor only. The micro panel will operate
on locally programmed values and ignore all commands
from the remote devices. 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: Remote
Start/Stop, Cooling Setpoint, Load Limit, and History
Buffer Request. If the unit receives no valid ISN trans-
mission 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. Re-
turn 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
Unit control is based on leaving chilled liquid temp.
Refer to section on Capacity Control for details on load-
ing and unloading sequences.
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 Imperial
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 Scientific
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 equal-
ize average run hours between systems on chillers with 2
refrigerant systems. Auto lead/lag allows automatic lead/
lag of the two systems based on an average run hours of
the compressors in each system. A new lead/lag assign-
ment is made whenever all compressors shut down. The
micro will then assign the “lead” to the system with the
shortest average run time.
Option 9 – Condenser Fan Control Mode
(YCAL0043-0253 Only):
F A N C O N T R O L
D I S C H A R G E P R E S S U R E
Condenser fans are controlled by discharge pressure
only. This mode may only be chosen when discharge
pressure transducers are installed. YCAL0287-0377 are
fixed in the fan control by discharge pressure mode and
cannot be reprogrammed.
or