84
YORK INTERNATIONAL
NOTE: If a power failure should again occur, the above
process will again need to be repeated to bring
the chiller back on line.
In the unlikely event the low battery message should
ever appear, it will require the RTC Chip U13 on the Mi-
croprocessor Board (Fig. 15) to be replaced. Care should
be taken to assure that the chip is properly installed.
Pin 1 (dimple in the top of the chip) must be oriented as
shown (Fig. 15). The part number for the RTC Chip is
031-00955-000.
CRANKCASE HEATER
The crankcase heater for a compressor will be ON
whenever the compressor is not running. The heater is
interlocked into the compressor motor contactor and is
not controlled by the microprocessor.
The purpose of the crankcase heater is to prevent the
migration of refrigerant to the crankcase during shutdown
assuring proper lubrication of the compressor on start-up.
Anytime power is removed from the chiller for more than
an hour, the crankcase heater should be left on for 24
hours prior to start. This can be accomplished by apply-
ing 115VAC to the control panel.
EVAPORATOR HEATER
The evaporator heater prevents water standing in the
evaporator from freezing. Whenever outdoor ambient tem-
perature drops below 40°F, the microprocessor will turn
the evaporator ON. If temperature rises above 45°F, the
heater will be turned off.
METRIC DISPLAY
The control panel is capable of providing displays of pres-
sure and temperature in metric values. Temperatures will
be displayed in °C and pressures in kPa.
A Metric to English temperature conversion table is pro-
vided on the rear cover of this manual. Pressure can be
converted from PSI to KPa using the formula PSI x 6.89
= kPa.
To obtain panel displays in metric, Switch 5 of Dip Switch
S1 on the Microprocessor Board must be placed in the
OPEN position (Page 43). The positioning of this switch
can then be verified by pushing the OPTIONS key and
verifying that METRIC UNITS READOUT is programmed
(Page 44).
EMS/BAS CONTROLS
The microprocessor is capable of REMOTE START/
STOP, REMOTE UNLOADING (Pulldown demand limit-
ing), and REMOTE SETPOINT RESET. These functions
can be easily utilized by connecting user supplied dry
contacts to the terminals on the TB3 Terminal Block.
REMOTE START/STOP BY A CYCLING DEVICE OR
TIME CLOCK
Remote START/STOP is accomplished by connecting a
time clock or other dry contact in series with the flow
switch on terminals 13 & 14. See Fig. 14 for the location
of the terminals. The contact must be closed to allow
the chiller to run. Any time the contact opens, the chiller
will shut down and the following status message will be
displayed.
Wiring from these contacts should not exceed 25 ft. and
should be run in grounded conduit that does not carry
any wiring other than control wiring. Additionally, if an
inductive device (relay, contactor) is supplying these
contacts, the coil of the device must be suppressed with
a user supplied YORK P/N 031-00808 suppressor.
REMOTE SETPOINT RESET
(REMOTE RESET TEMP RANGE)
Remote Setpoint Reset allows resetting the setpoint
upward from the programmed value in memory. This is
accomplished by connecting a dry contact between
terminals 13 & 17. See Fig. 14 for the location of these
terminals. Closing the contact for a defined period of time
allows reset of the setpoint upward by up to 40°F above
the setpoint programmed in memory.
The maximum desired reset must be programmed into
memory and can be a value of 02 to 40°F. This value will
vary according to the users requirements. To program
the reset, press the REMOTE SETPOINT TEMP RANGE
key. The following message will appear.
The display will indicate the REM SETPOINT which is
always equal to the chilled liquid setpoint plus the offset
from the reset signal. The display will also show the REM
RANGE which is the same as the maximum reset re-
quired. Key in the maximum reset for the REM RANGE
and press the ENTER Key to store the new value in
memory.
Once the maximum reset is programmed, it will require
a contact closure of 21 seconds to achieve the maxi-
mum reset. Closure for less than 21 seconds will pro-
vide a smaller reset. For noise immunity, the micro will
ignore closures of less than 1 second.
S Y S # 1
N O
R U N
P E R M
S Y S # 2
N O
R U N
P E R M
R E M
S E T P O I N T
=
4 0 . 0
R E M
R A N G E
=
2 0
D E G F
Summary of Contents for YCWJ45EE0
Page 29: ...FORM 150 24 NM27 YORK INTERNATIONAL 29 CONTROL CIRCUIT With I O Expansion Board LD02106...
Page 30: ...30 YORK INTERNATIONAL FIG 9 SYSTEM WIRING...
Page 31: ...FORM 150 24 NM27 YORK INTERNATIONAL 31 LD02678...
Page 35: ...FORM 150 24 NM27 YORK INTERNATIONAL 35 LD02679...
Page 36: ...36 YORK INTERNATIONAL MICROPANEL CONNECTION DIAGRAM With I O Expansion Board LD02107...
Page 37: ...FORM 150 24 NM27 YORK INTERNATIONAL 37 LD02108...