Fig. 6 – leaving water temperature control, Unit controls – York YCAL0080SC User Manual
Page 86
YORK INTERNATIONAL
86
FIG. 6 – LEAVING WATER TEMPERATURE CONTROL
TABLE 32 – LEAVING CHILLED LIQUID CONTROL FOR 6 COMPRESSORS (8 STEPS)
TABLE 33 – LEAVING CHILLED LIQUID CONTROL FOR 4 COMPRESSORS (6 STEPS)
20 sec.
30 sec.
60 sec.
control range
60 sec.
unloading
unloading
unloading
(no compressor staging)
loading
42.5°F
43.5°F
44.0°F
46.0°F
48.0°
(5.8°C)
(6.4°C)
(6.7°C)
(7.8°C)
(8.9°C)
Low Limit
Setpoint
High limit
Leaving Water Temp. Control – Compressor Staging
Setpoint = 46.0°F (7.8°C) Range = +/- 2°F(1.1°C)
LWT
LEAD SYSTEM
LAG SYSTEM
*STEP
COMP 1
COMP 2
COMP 3
COMP 1
COMP 2
COMP 3
0
OFF
OFF
OFF
OFF
OFF
OFF
1
ON+HG
OFF
OFF
SEE NOTE 1
OFF
OFF
OFF
2
ON
OFF
OFF
OFF
OFF
OFF
3
ON
OFF
OFF
SEE NOTE 2
ON
OFF
OFF
4
ON
ON
OFF
SEE NOTE 3
OFF
OFF
OFF
5
ON
ON
OFF
ON
OFF
OFF
6
ON
ON
OFF
ON
ON
OFF
7
ON
ON
ON
ON
ON
OFF
8
ON
ON
ON
ON
ON
ON
LEAD SYSTEM
LAG SYSTEM
*STEP
COMP 1
COMP 2
COMP 1
COMP 2
0
OFF
OFF
OFF
OFF
1
ON+HG
OFF
SEE NOTE 1
OFF
OFF
2
ON
OFF
OFF
OFF
3
ON
OFF
SEE NOTE 2
ON
OFF
4
ON
ON
SEE NOTE 3
OFF
OFF
5
ON
ON
ON
OFF
6
ON
ON
ON
ON
* STEP can be viewed using the OPER DATA key and scrolling to COOLING DEMAND.
Unit Controls