York MILLENIUM YCAS Series, Установка, эксплуатация и обслуживание, Страница: 139 / 156

139
YORK INTERNATIONAL
FORM 201.18-NM6
temperatures. If operation is occasionally needed be-
low -17°C (1°F), the cutout should be set at 00.0°F. This
will allow operation at any temperature, as the micro will
only recognize temperatures above -17°C (1°F). Tem-
peratures below -17°C (1°F) will not be displayed.
To program the Low Ambient Cutout, key in the re-
quired setting and press the Enter key to store the value
into memory and scroll to the next display.
Operation below -17°C (1°F) may oc-
casionally cause nuisance low pres-
sure safety shutdowns. This will gen-
erally not cause a problem provided
ambient temperature is not expected
to be below -17°C (1°F) for more than
a short time.
Low Leaving Liquid Temperature CutOut
The Low Leaving Liquid Temperature Cutout protects
the evaporator from damage due to ice build up caused
by operation below the chilled liquid freezing point.
If the leaving chilled liquid temperature (water or gly-
col) drops below the cutout point, the chiller will shut
down. The chiller will restart automatically when tem-
perature rises more than 2°C (4°F) above the cutout
point and cooling demand exists.
If the Dip Switch on the microprocessor board is set for
“Water Cooling” (see Section 3.7, page 119) the cutout is
automatically set at 2°C (36°F) and cannot be repro-
grammed. If the Switch is set for “Brine Cooling” (gly-
col) the cutout can be programmed between -13 through
-2°C (8.0 - 36.0°F). The cutout should normally be set to
2°C (4°F) below the setpoint minus the range, i.e. 1.1°C
(setpoint) – 1.1°C (range) - 2.2°C = -2.2°C (see Section
6, page 130).
To program the Leaving Liquid Temperature Cutout, key
in the required setting and press the Enter key to store
the value into memory and scroll to the next display.
High Motor Current Unload Point
The Motor Current Unload point is used to avoid a high
motor current safety shutdown by unloading a compres-
sor, if current draw approaches the maximum limit cut-
cutout should be set to the saturated refrigerant pressure
equivalent to 10°C (18°F) below the lowest temperature
of the programmed chilled liquid Control Range (Section
6). This programmable value is password protected.
To program the Suction Pressure Cutout, key in the re-
quired setting and press the Enter key to store the value
into memory and scroll the next display.
High Ambient Temperature CutOut
The High Ambient Cutout is used to select the ambient
temperature above which the chiller may not operate.
If the ambient temperature rises 1°C (1°F) above this
point, the chiller will shut down. Restart will occur auto-
matically, when temperature falls more than 1°C (1°F)
below the cutout and cooling demand is present.
This cutout is normally set at 54°C (130°F) to allow
operation to the absolute maximum temperature capa-
bility of the electromechanical components; however,
values between 38 - 54°C (100.0 - 130.0°F) are ac-
cepted. This programmable value is password protected.
To program the High Ambient Cutout, key in the re-
quired setting and press the Enter key to store the value
into memory and scroll to the next display.
Low Ambient Temperature CutOut
The Low Ambient Cutout is used to select the ambient
temperature below which the chiller may not operate.
If the ambient temperature falls 1°C (1°F) below this
point, the chiller will shut down. Restart will occur auto-
matically, when temperature rises more than 1°C (1°F)
above the cutout and cooling demand is present (see
also Section 2.5 page 112). This programmable value is
password protected.
If the SW1 Dip Switch on the Microprocessor Board
is set for “Standard Ambient Control” (see Section
3.7) the low ambient cutout is set at -4°C (25°F) and
is NOT programmable. If the Dip Switch is set for
“Low Ambient Control”, programming of the cutout
between 8 - 10°C (00.0 - 50.0°F) is allowed. This al-
lows higher values than -4°C (25° F) to be programmed
to shut down the chiller when other cooling methods
become operational. Values below -4°C (25°F) can be
used for applications requiring chiller operation at lower
H I G H A M B I E N T T E M P
C U T O U T = 1 3 0 . 0 ° F
L O W A M B I E N T T E M P
C U T O U T = 2 5 . 0 ° F
L E A V I N G L I Q U I D T E M P
C U T O U T = 3 6 . 0 ° F
H I G H M O T O R C U R R E N T
U N L O A D = 1 0 5 % F L A
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