Carrier AQUAFORCE 30XA080-500 Controls, Start-up, Operation, Service And Troubleshooting Instructions

Also see for AQUAFORCE 30XA080: Installation instructions Controls, start-up, operation, service and troubleshooting instructions Installation instructions Product data

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Carrier AQUAFORCE 30XA080-500 Controls, Start-up, Operation, Service And Troubleshooting Instructions Manual pdf 38 page image

38If the Start and End Time remain at the factory default(0:00), then the unit is not programmed for Night Time/LowNoise Operation.To configure this option with the Touch Pilot™ display:To configure this option with the Navigator™ display:Ramp Loading — Ramp Loading limits the rate ofchange of the leaving fluid temperature. If the unit is in a Cool-ing mode and configured for Ramp Loading Select (RampLoading Select, RL.S), the control makes two comparisonsbefore deciding to increase capacity. First, the control calcu-lates the temperature difference between the control point andleaving fluid temperature. If the difference is greater than 4° F(2.2° C) and the rate of change (°F or °C per minute) is morethan the configured Cool Ramp Loading rate (Cooling RampLoading, CRMP), then the control does not allow any increaseof capacity.To configure this option with the Touch Pilot display:To configure this option with the Navigator display:Temperature Reset — Temperature reset is a valueadded to the basic leaving fluid temperature set point and theresulting sum of these values is the new control point. When anon-zero temperature reset is applied, the chiller controls to thenew control point, not the set point. The type of temperature re-set is configured with the Cooling Reset Type (Cooling ResetSelect, CRST) variable. Four types of temperature reset areavailable: Return Water Reset, Outside Air Temperature Reset,Space Temperature Reset, and 4-20 mA Temperature Reset.Under normal operation, the chiller will maintain a constantentering or leaving fluid temperature, based on the configura-tion, approximately equal to the chilled fluid set point. As thecooler load varies, the cooler fluid temperature difference willchange in proportion to the load. For example, if the chiller wasselected for a Entering to Leaving Water Temperature differ-ence of 10 F (5.5 C) at full load, at 50% load the temperaturedifference would be 5 F (2.2 C). See Fig. 22. Because thechange in temperature through the cooler is a measure of thebuilding load, the temperature difference reset is the averagebuilding load. Usually the chiller size and fluid temperature setpoint are selected based on a full load condition. At part load,the fluid temperature set point may be lower than required. Ifthe fluid temperature were allowed to increase at part load, theefficiency of the machine would increase. The chiller can alsobe set for return water temperature control. See Fig. 23.Other indirect means of estimating building load and con-trolling temperature reset are also available and are discussedbelow.To verify that reset is functioning correctly, subtract the Set-point Select (Current Setpoint, SETP) from the Control Point(Control Point, CTPT) to determine the degrees reset.RETURN WATER RESET — The control system is capableof performing fluid temperature reset based on cooler fluidtemperature difference. Because the change in temperaturethrough the cooler is a measure of the building load, the tem-perature difference reset is, in effect, an average building loadreset method.Return Water Temperature Reset allows for the chilledwater temperature set point to be reset upward as a function ofthe fluid temperature difference (building load).NOTE: Return Water Temperature Reset should not be usedwith variable cooler flow rate systems.To use Return Water Temperature Reset, four variablesmust be configured. Cooling Reset Type (Cooling ResetSelect, CRST) must be enabled. The variable Delta T No ResetTemp (Delta T No Reset Value, CRT1) should be set to thecooler temperature difference (T) where no chilled water tem-perature reset should occur. The variable Delta T Full ResetTemp (Delta T Full Reset Value, CRT2) should be set to thecooler temperature difference where the maximum chilledwater temperature reset should occur. The variable DegreesCool Reset (Cooling Reset Deg. Value, DGRC) should be setto the maximum amount of reset desired.To configure this option with the Touch Pilot display:DISPLAY NAME PATH LINENO. VALUEStart Hour Main MenuConfigUser 39 Default: 00:00End Hour Main MenuConfigUser 40 Default: 00:00Capacity Limit Main MenuConfigUser 41 Default: 100%ITEM ITEM EXPANSION PATH VALUELS.ST Night Low NoiseStart ConfigurationOPTN Default: 00:00LS.ND Night Low NoiseEnd ConfigurationOPTN Default: 00:00LS.LT Low Noise CapacityLim ConfigurationOPTN Default: 100%DISPLAY NAME PATH LINENO. VALUERamp LoadingSelectMain MenuConfigUSER 5 YesCooling RampLoadingMain MenuSetpoint 14Range: 0.2 to 2.0 °F(0.1 to 1.1 °C)Default: 1.0 °F (0.5 °C)ITEM ITEMEXPANSION PATH VALUERL.S Ramp LoadSelect ConfigurationOPTN YesCRMP Cool RampLoading SetpointsCOOLRange: 0.2 to 2.0 °F(0.1 to 1.1 °C)Default: 1.0 °F (0.5 °C) DISPLAYNAME PATH LINENO. VALUECooling ResetSelectMainMenuConfigUSER 19 Default =0(No Reset)2 (Delta T)Delta T NoReset Temp MainMenuSetpointSETPOINT 7 Default =0 F (0 C)Delta T FullReset TempMainMenuSetpointSETPOINT 8 Default =0 F (0 C)Cooling ResetDeg. Value MainMenuSetpointSETPOINT 13 Default =0 F (0 C)