York YCAV0267E, Installation Operation & Maintenance

Page: 284 / 350

284
JOHNSON CONTROLS
FORM 201.21-NM3 (616)
Low Ambient Cutout
MICRO PANEL
PROGRAM KEY (CON'T)
The low ambient temp cutout allows programming the
outdoor temperature at which it is desired to shut down
the chiller to utilize other methods of cooling.
The cutout is programmable between –2.0°F (-18.9°C)
and 50°F (10.0 C) with a 25°F (-3.9°C) default.
Low Leaving Liquid Temp Cutout
PROGRAM ◄DEF XXXXX LO XXXXX HI XXXXX
LEAVING LIQUID TEMP CUTOUT = XXX.X °F
PROGRAM ◄DEF XXXXX LO XXXXX HI XXXXX
MOTOR CURRENT LIMIT = XXX % FLA
PROGRAM ◄DEF XXXXX LO XXXXX HI XXXXX
PULLDOWN CURRENT LIMIT = XXX % FLA
PROGRAM ◄DEF XXXXX LO XXXXX HI XXXXX
LOW AMBIENT TEMP CUTOUT = XXX.X °F
The leaving chilled liquid temp cutout is programmed
to avoid freezing the evaporator due to excessively low
chilled liquid temperatures. The cutout is automati-
cally set at 36°F (2.2 °C) in the Water Cooling mode
and is programmable in the Glycol Cooling mode. In
the Glycol Cooling Mode, the cutout is programmable
from 11.0°F – 36.0°F (-11.7 – 2.2°C) with a default of
36.0°F (2.2°C).
Motor Current Limit
The motor current limit %FLA is programmable. This
allows the micro to limit a system before it faults on high
current. Typically, the limit point is set at 100%. The
unload point is programmable from 30 – 100% with a
default of 100%.
Pulldown Current Limit
The pulldown current limit %FLA is programmable.
This allows the micro to limit a system on pulldown
limiting for the purpose of peak time energy savings.
Typically, the limit point is set at 100%. The pulldown
limit point is programmable from 30 – 100% with a
default of 100%. Be aware when using pulldown mo-
tor current limit, the chiller may not be able to load to
satisfy temperature demand
Pulldown Current Limit Time
The pulldown current limit time is programmable. This
allows the micro to limit a system on pulldown limiting
for a defined period of time for the purpose of peak time
energy savings. The pulldown limit point is program-
mable from 0 – 255 with a default of 0 Min.
Suction Superheat Setpoint
PROGRAM ◄DEF XXXXX LO XXXXX HI XXXXX
PULLDOWN CURRENT LIMIT TIME = XXX MIN
The suction superheat setpoint is programmable from
8.0 – 12.0°F (4.4 – 8.3°C) with a 10.0°F (5.6°C) default.
Typically the superheat control will be programmed
for 10.0 °F. Higher superheats of 10-12°F will reduce
the risk of liquid carry over and are preferred by some
users.
Unit ID Number
PROGRAM ◄DEF XXXXX LO XXXXX HI XXXXX
SUCTION SUPERHEAT SETPOINT = XXX.X °F
For purposes of remote communications, multiple chill-
ers may be connected to an RS-485 communications bus.
To allow communications to each chiller, a chiller ID
number may be programmed into memory. On a single
chiller application, the value will be “0”.
PROGRAM ◄DEF XXXXX LO XXXXX HI XXXXX
REMOTE UNIT ID NUMBER = X