Johnson Controls YEWS Series, Installation, Operation And Maintanance Instructions

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Instructions for capacity control (AC mode for example)
Ts
：
Leaving chilled water temperature setpoint (LEL TEMP SET )
D
：
Differential of Leaving chilled water temperature (LEL TEMP CR)
Db
：
Differential buffering value
When leaving chilled water temperature
≥
(Ts + D), the compressor will load. when leaving chilled water
temperature
≥
(Ts - D) and
≤
(Ts + D) , the comrepssor will operate fuzzy control logic. when leaving chilled
water temperature
≥
(Ts
–
D- Db) and
≤
(Ts - D) , the comrepssor will unload. When leaving chilled water
temperature
≤
(Ts
–
D- Db) , the compressor will be cycling shut down.
By setting the value of Ts, D and Db, the temperature range of different running
mode(Hold/Unload/Load/Stop) of compressor can be adjusted.
Loading
Holding
Unloading
Emergency Stop
Low
temperature
High
temperature
Ts+D
Ts
Ts-D
Ts-D-Db
YEWS-E Water Cooling Screw Chiller/Heat Pump
32