FORM 150.40-NM20
29
YORK INTERNATIONAL
(YCHA100)
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OPTIONAL LOADING/UNLOADING [LEAVING WA-
TER TEMPERATURE (LWT) CONTROL]
Optional loading and unloading of cylinders can be
accomplished in response to leaving chilled water tem-
perature as sensed by the Micro Logic Board.
LWT Control is selected by placing Switch #3 ON or
J10 IN on the Micro Logic Board. Various cooling ranges
can then be selected depending upon the allowable
deviation from setpoint.
Control Ranges can be selected on the front panel with
the Cooling Range Rotary Switch. The Cooling Range
Codes and their respective cooling ranges are listed at
the right.
NOTE: On LWT Control, the cooling ranges on the Con-
trol Panel are no longer meaningful.
CAUTION: Selection of the Cooling Range should be
made according to the deviation from
setpoint which can be tolerated and whether
more than normal system cycling of the
loaders and compressor is experienced due
to a cooling range which is too tight.
Page 30 shows a listing of each cooling range code
along with the temperatures at which each stage loads
and unloads.
CODE RANGE
0 + 1.0°F
1 + 1.2°F
2 +1.4°F
3 +1.5°F
4 +1.6°F
5 +1.8°F
6 +1.9°F
7 +2.0°F
LOADING/UNLOADING
[RETURN WATER TEMPERATURE (RWT)
CONTROL – STANDARD]
Loading/Unloading of cylinders is accomplished in re-
sponse to return chilled water temperature as sensed
by the Micro Logic Board. Cooling Ranges from 6 to
14°F can be selected to control loading/unloading. A
typical example is illustrated below.
RWT Setpoint = 55°F
Cooling Range = 10°
System Switch = ON
J10 on Micro Logic = OUT
or
Sw. 3 on Micro = OFF
RWT CONTROL
Return Water
Temp. °F
55 -------------------- --------- Loader ON Stage 4 ----------------------- -------------------------------------
Cooling 52.5------------------ --------- Loader ON Stage 3 ----------------------- – Loader OFF Stage 4
Range 50.0------------------ --------- Loader ON Stage 2 ----------------------- – Loader OFF Stage 3
*10°F 47.5------------------ --------- Compressor ON (Unloaded) Stage 1 – Loader OFF Stage 2
45 -------------------- --------- Compressor OFF -------------------------- – Compressor OFF Stage 1
*10°F ÷ 4 stages = 2.5°F between stages of loading.
Temperature
Fall
Temperature
Rise
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