Specifications

77
JOHNSON CONTROLS
Form 201.28-NM1.EN.PED/CE (0211)
8
Pulldown Current Limit Time
PROGRAM DEF LO HI
PULLDOWN CURRENT LIMIT TIME = XXX MIN
The pulldown current limit time is programmable. This
allows the microprocessor 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
programmable from 0 to 255 with a default of 0 Min.
Subcooling Setpoint
PROGRAM DEF LO HI
SUBCOOLING SETPOINT = XX.X °F
The liquid subcooling superheat setpoint is programmable
from 0.0 to 11.1°C (0.0 to 20.0°F) with a 2.8°C (5.0°F)
default. Typically the subcooling control will be
programmed for 2.8°C (5.0 °F).
Unit ID Number
PROGRAM DEF LO HI
REMOTE UNIT ID NUMBER = X
For purposes of remote communications, multiple
chillers 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”.
Sound Limit Setpoint
PROGRAM DEF LO HI
SOUND LIMIT SETPOINT = XXX %
The sound limit setpoint is programmable from 0 to
100 % with a 0% default. 0% allows operating up to
the full speed capability of the unit with no sound
limiting. Typically the sound limit control setting will be
programmed for 0 % unless sound limiting is utilized on
the chiller. Sound limiting will only permit the unit to run
to a frequency less than the maximum speed capability
of the unit. Programming a value of 1% would be the
minimum sound limiting that can be programmed and
100% will be the maximum. 100% will only allow the
unit speed to operate at the minimum frequency. Usually,
the sound limit % will be programmed somewhere
between 0 and 100% according the limiting needed to
satisfy the sound requirements of the site. Typically,
sound limiting will be utilized in areas sensitive to noise
during night-time hours. The sound limit display will
only be present if the sound limit option is programmed
at the factory.
Eductor Differential
PROGRAM DEF LO HI
EDUCTOR DIFFERENTIAL = XX.X °F
The eductor temperature differential is programmable
from 0°C to 10.0°C (0°F to 50.0°F). The default value is
5.0°F. The programmed temperature assures the micro
will sense a loss of educator oil flow, if the temperature
differential rises. A small differential of 2.8°C (5.0°F) is
recommended.
Eductor Safety Time
PROGRAM DEF LO HI
EDUCTOR SAFETY TIME = XXXX MIN
The educator safety time allows programming the
time period the system is permitted to run if the safety
threshold is exceeded. The safety time is programmable
for 10 minutes to 1000 minutes with 10 minutes as
the default. A minimum safety time is recommended
to assure the compressor is not starved for oil for long
periods of time due to the educator circuit not siphoning
oil from the evaporator. A minimum time of 10 minutes
is recommended as the program point.
Motor Temperature Unload
PROGRAM DEF LO HI
MOTOR TEMPERATURE UNLOAD = XXX.X °F
The motor temperature unload is programmable from
65.6°C (150.0°F) to 121.1°C 250.0°F. The default value
is 115.5°C (240.0°F). The programmed temperature
assures the micro will sense a rise in motor temperature
due to a lack of compressor cooling. If the temperature
rises above the programmed threshold, the system will
unload the compressor by reducing speed. An unload
temperature of 115.5°C (240.0°F) is recommended to
assure the system does provides maximum capacity.
Default Values
A listing of the low limits, high limits, and default values
for each of the programmable values is given in Table 8.
Note that the Imperial units are exact values while the
Metric units are only approximate.