YORK INTERNATIONAL
91
FORM 155.16-O3
LAST 7 DAYS = XXX; TOTAL PURGES = XXXXX
Total purges in
Total purges to date
last 7 days
over lifetime of unit
LiBr CONCENTRATION CALCULATOR
The concentration calculator allows the service techni-
cian to determine the concentration of any lithium bro-
mide solution without referring to the traditional “PTX”
chart. By entering a SOLUTION TEMPERATURE and
REFRIGERANT SATURATION TEMPERATURE or
PRESSURE (PSIA), the CONCENTRATION is automati-
cally calculated. To use the calculator, proceed as fol-
lows:
1. Refer to “Programming the IsoFlow Control Center”
section of this book and gain access to PROGRAM
MODE by performing steps 1 thru 8.
PROGRAM MODE, SELECT SETPOINT
is displayed.
The user will have access to the calculator for 10 min-
utes. When 10 minutes have elapsed, access to PRO-
GRAM mode will be automatically disabled. The user
will have to repeat this step to regain access to PRO-
GRAM mode.
2. Press OPTIONS key.
WELCOME TO LIBR CONCENTRATION CALCULATOR
is displayed.
3. Press OPTIONS key.
BROMIDE SOLUTION TEMP = 0.0°F
is displayed.
4. Using the Entry keys, enter a solution temperature.
Use leading zeroes where necessar y (i.e.,
095.0°F).The CANCEL key can be used at any time
to cancel any entry.
5. Press ENTER key.
6. Press ADVANCE DAY/SCROLL key.
SATURATION TEMP = 0.0°F; PRS = 0.00 PSIA
is displayed.
7. The user has a choice of entering either a refrigerant
saturation temperature or pressure. Whichever one
is entered, the program automatically calculates and
displays the other. Based upon your choice, use ei-
ther procedure A. or B. below:
A. To enter the temperature, use the Entry keys (use
leading zeroes where necessary; i.e., 095.0°F).
Press the ENTER key. The corresponding pres-
sure is displayed.
– or –
B. To enter the pressure, press the * (asterisk) key.
The cursor is moved to the first changeable digit of
the pressure entry and “???.?” is displayed for
the temperature value. Using the Entry keys, en-
ter the pressure value (use leading zeroes where
necessary; i.e., 0.35 PSIA). Press the ENTER key.
The corresponding temperature is displayed.
8. Press ADVANCE DAY/SCROLL key.
SOLUTION CONCENTRATION = XX.X%
is displayed.
9. If it is desired to view the entries that were just made,
press the ADVANCE DAY/SCROLL key repeatedly.
– or –
If it is desired to perform further concentration calcu-
lations for the remainder of the 10 minute period, press
the ADVANCE DAY/SCROLL key to go back to the
beginning.
– or –
If it is desired to exit the calculator routine, press the
PROGRAM key.
SYSTEM SETPOINTS
The system setpoints may be programmed by the sys-
tem operator. The Setpoints keys are located on the
Control Center keypad (see Fig. 1). To program, see “Pro-
gramming System Setpoints”, page 94. The following is
a description of these setpoints.
LEAVING WATER TEMP – This setpoint determines the
leaving chilled water temperature that the unit will main-
tain. The range is 40-77°F. The default value is 44°F.
However, each unit has a minimum allowable setpoint
that is determined by the design of that unit. The value is
programmed into the Control Center at the York factory
and must never be changed. The software will prevent
operator personnel from entering a value that is lower
than the factory programmed value.
OUT OF RANGE – TRY AGAIN
is displayed if an attempt
is made to enter a lower value. If the Micro Board or
Real Time Clock Chip (IC U16 on Micro Board) is re-
placed, this minimum allowed value must be entered by
a qualified service technician.
An “Energy Management System” (EMS) can be con-
nected to the Control Center to change this setpoint from
a remote location while the Control Center is operating
in REMOTE mode. Refer to “Field Control Modifications
Diagram”, Form 155.16-PA3 for details of Remote Set-
point Reset Operation.
PURGE PUMP SERVICE INTERVAL – This setpoint
Summary of Contents for MILLENNIUM YIA-HW-14F3
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