Application Considerations
AMBIENT LIMITATIONS
Trane chillers are designed for year- round applications in ambients from 0°F to 115°F. For operation below 0°F or above 115°F, contact the localTrane sales office. If hot gas bypass is used, operating ambients vary depending upon unit size (see the “General Data” section of this catalog).
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Low Ambient Operation
Minimum operating ambient temperatures for standard unit selections and units with hot gas bypass are shown in the “General Data” section of this catalog.
Minimum ambient temperatures are based on still conditions (winds not exceeding five mph). Greater wind velocities will result in a drop in head pressure, therefore increasing the minimum starting and operating ambient temperatures.
Optional low ambient units use a electronic low ambient damper control
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High Ambient Operation
Maximum cataloged ambient temperature operation of a standard Trane chiller is 115°F. Operation at design ambients above 115°F can result in excessive head pressures. For operation above 115°F, contact your localTrane sales office.
CONTROLS
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Temperature Controller
In order to provide stable system operation and to prevent excessive compressor cycling, the temperature control sensor in all
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All IntelliPak
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Pumpdown
CGAF
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Hot Gas Bypass
Hot gas bypass provides more stable leaving solution temperature control at light load conditions.The compressor runs continuously for a
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Loss of Flow Protection
Loss of flow may result in evaporator freeze up. Full chilled solution flow must be maintained through the evaporator while compressors are operating.
A flow switch used as a safety interlock is always recommended for CGA units.
The CGAF
WATERFLOW LIMITS
The minimum water flow rates are given in the “General Data” section of this catalog. Evaporator flow rates below the tabulated values will result in laminar flow causing scaling, stratification,
The maximum evaporator water flow rate is given in the “General Data” section. Flow rates exceeding those listed will result in excessive tube erosion and very high pressure drop across the evaporator.
Trane recommends that constant water flow be maintained at all times through the evaporator. Because the temperature controller strictly senses temperature, variable flow through the evaporator may result in loss of control and localized freezing or nuisance low temperature cutouts. Consult your local Trane sales engineer if your application requires varying flows.
TEMPERATURE LIMITS
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Leaving SolutionTemperature range
The minimum leaving solution temperature set point is dependent on the number of capacity stages and the temperature difference across the evaporator.Water supply temperature set points less than these values result in suction temperatures at or below the freezing point of cold water.
A glycol solution is required for operation below the recommended minimum set points. Refer to the “Performance Adjustment Factors” section of this catalog to determine the minimum leaving chilled solution set
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