Carrier 19XR User Manual

Also see for AquaEdge 19XRV series: Start-up, operation and maintenance instructions Start-up and service instructions Installation instructions Start-up, operation and maintenance instructions Start-up and service instructions

Contents

61Protecting the VFD Configuration1. Select parameter P.051 from the VFD keypad.2. Press the softkey to access the parameter. Azero will be displayed.3. Use the arrow key to increment the value to 26. This isthe password number.4. Press the softkey to save the value. P.051 willby displayed.NOTE: Parameter programming is disabled when thePASSWORD LED is on and enabled when the PASS-WORD LED is off.5. Select parameter P.006 from the VFD Keypad.6. Press the softkey to access the parameter.7. Use the arrow key to increment the value to 107. Thisis the password number to restrict displaying the remain-ing P, and all of the H and r parameters.8. Press the softkey to save the value.Modify Minimum and Maximum Load Points (∆T1/P1; ∆T2/P2) If Necessary — These pairs of chiller load points, locatedon the OPTIONS screen, determine when to limit guide vanetravel or open the hot gas bypass valve when surge preventionis needed. These points should be set based on individualchiller operating conditions.A label that lists the configuration values of the controls islocated on the inside of the unit’s control panel. These valuesare based upon the original selection of the chiller. Jobsite con-ditions may require a slight modification to these parameters.If after configuring a value for these points, surge preven-tion is operating too soon or too late for conditions, these pa-rameters should be changed by the operator.An example of such a configuration is shown below.Refrigerant: HCFC-134aEstimated Minimum Load Conditions:44 F (6.7 C) LCW45.5 F (7.5 C) ECW43 F (6.1 C) Suction Temperature70 F (21.1 C) Condensing TemperatureEstimated Maximum Load Conditions:44 F (6.7 C) LCW54 F (12.2 C) ECW42 F (5.6 C) Suction Temperature98 F (36.7 C) Condensing TemperatureCalculate Maximum Load — To calculate the maximum loadpoints, use the design load condition data. If the chiller full loadcooler temperature difference is more than 15 F (8.3 C), esti-mate the refrigerant suction and condensing temperatures atthis difference. Use the proper saturated pressure and tempera-ture for the particular refrigerant used.Suction Temperature:42 F (5.6 C) = 37 psig (255 kPa) saturatedrefrigerant pressure (HFC-134a)Condensing Temperature:98 F (36.7 C) = 120 psig (1827 kPa) saturatedrefrigerant pressure (HFC-134a)Maximum Load ∆T2:54 – 44 = 10º F (12.2 – 6.7 = 5.5º C)Maximum Load ∆P2:120 – 37 = 83 psid (827 – 255 = 572 kPad)To avoid unnecessary surge prevention, add about 10 psid(70 kPad) to ∆P2 from these conditions:∆T2 = 10º F (5.5º C)∆P2 = 93 psid (642 kPad)Calculate Minimum Load — To calculate the minimum loadconditions, estimate the temperature difference the cooler willhave at 10% load, then estimate what the suction and condens-ing temperatures will be at this point. Use the proper saturatedpressure and temperature for the particular refrigerant used.Suction Temperature:43 F (6.1 C) = 38 psig (262 kPa) saturatedrefrigerant pressure (HFC-134a)Condensing Temperature:70 F (21.1 C) = 71 psig (490 kPa) saturatedrefrigerant pressure (HFC-134a)Minimum Load ∆T1 (at 20% Load): 2 F (1.1 C)Minimum Load ∆P1:71 – 38 = 33 psid (490 – 262 = 228 kPad)Again, to avoid unnecessary surge prevention, add 20 psid(140 kPad) at ∆P1 from these conditions:∆T1 = 2 F (1.1 C)∆P1 = 53 psid (368 kPad)If surge prevention occurs too soon or too late:The differential pressure (∆P) and temperature (∆T) can bemonitored during chiller operation by viewing ACTIVEDELTA P and ACTIVE DELTA T (HEAT_EX screen). Com-paring SURGE/HGBP DELTA T to ACTIVE DELTA T will de-termine when the SURGE PREVENTION function will occur.The smaller the difference between the SURGE/HGBP DELTAT and the ACTIVE DELTA T values, the closer to surgeprevention.Units with VFD — On units with VFD further adjustments canbe made if response to surge prevention or protection is notfunctioning as desired. VFD GAIN and VFD INCREASE STEPcan be adjusted to allow for more aggressive changes in speedwhen surge prevention or protection is active.CONFIGURE DIFFUSER CONTROL IF NECES-SARY — If the compressor is equipped with a variable dif-fuser, (size 5 compressor) access the SETUP2 screen. Scroll toDIFFUSER CONTROL and press the softkey.Compare the diffuser and guide vane values (GUIDE VANE25% LOAD PT, GUIDE VANE 50% LOAD PT, GUIDE VANE75% LOAD PT, DIFFUSER 25% LOAD POINT, DIFFUSER50% LOAD POINT, DIFFUSER 75% LOAD POINT) to thevalues located on the label inside the control panel. SeeFig. 12.Compressors with variable diffuser control have actuatorstested and stamped with the milliamp (mA) value that results in100% actuator rotation. This value is configured on theSETUP2 screen. It is labeled DIFFUSER FULL SPAN mA.MODIFY EQUIPMENT CONFIGURATION IF NECES-SARY — The EQUIPMENT SERVICE table has screens toselect, view, or modify parameters. Carrier’s certified drawingshave the configuration values required for the jobsite. Modifythese values only if requested.SERVICE Screen Modifications — Change the values onthese screens according to specific job data. See the certifieddrawings for the correct values. Modifications can include:• chilled water reset• entering chilled water control (Enable/Disable)• 4 to 20 mA demand limit• auto restart option (Enable/Disable)• remote contact option (Enable/Disable)ENTER↑ENTERENTER↑ENTERLOAD SURGE PREVENTIONOCCURS TOO SOONSURGE PREVENTIONOCCURS TOO LATEAt low loads(<50%)Increase P1 by2 psid (14 kPad)Decrease P1 by2 psid (14 kPad)At high loads(>50%)Increase P2 by2 psid (14 kPad)Decrease P2 by2 psid (14 kPad)ENABLE