60 YORK INTERNATIONAL
CAUTION: Selection of the Cooling Range should be
made according to the deviation from set
point which can be tolerated and whether
more than normal system cycling of the load-
ers and compressors is experienced due to
a cooling range which is too small. The fac-
tory recommends that Code 7 be used to
avoid cycling.
CODE RANGE
0 ± 0.55°C
1 ± 0.55°C
2 ± 0.70°C
3 ± 0.84°C
4 ± 0.89°C
5 ± 1.00°C
6 ± 1.05°C
7 ± 1.11°C
DUAL CIRCUIT UNITS
H. System Limitations: With a minimum Cooling Range
of 3.4°C and a maximum “Computed Setpoint” of
9.9°C, a maximum RWT Setpoint of 13.3°C can only
be achieved. Maximum RWT setpoints for various
cooling ranges can be computed by adding the cool-
ing range to 9.9°C.
With a maximum Cooling Range of 7.8°C and a mini-
mum “Computed” Setpoint of –9.9°C, a minimum
RWT Setpoint of –2.1°C can only be achieved. Mini-
mum RWT setpoints for various cooling ranges can
be computed by adding the cooling range to –9.9°C.
I. See Page 62 for determining loading and unloading
points.
Leaving Water Temperature (LWT) Control
Follow the steps below to set up the panel switches prior
to operating the chiller.
NOTE: YORK does not recommend utilizing LWT Con-
trol unless 6-8 stages of optional unloading are
present. Otherwise cycling and temperature fluc-
tuations may result.
A. Before any control panel switches are set, SW3 on
the Micro Logic Board must be placed in the ON po-
sition for LWT control.
B. Determine what system conditions must be met and
fill in the blanks below:
1. Desired LWT Setpoint =
2. *Desired Cooling Range =
(Temp. difference across cooler.)
*Select the Cooling Ranges from the chart below.
FIG. 46 – SELECT DATA DISPLAY SWITCHES SET AT 0,5
FIG. 45 – WATER COOLING RANGE SET AT 4 (5.6°C)
G.Verify the actual Design RWT Setpoint by placing the
Display Select Switches to 0.5. The actual design set-
point will be displayed along with a “–” sign if the set-
point is negative.
i.e.: 12.7 will be displayed (from Step C) if the Dis-
play Select Switches are set to 0,5. (See Fig. 46.)
FIG. 44 – “COMPUTED” SETPOINT SET AT 7.1
F. Set the Cooling Range Switch to the coded number
which represents the desired cooling range selected
in Step B.
i.e.: Code “4” = 5.6°C from Step B (See Fig. 45)
LD01875
LD01874
LD01873
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