Carrier AQUASNAP 30RAP010-150 Controls, Start-up, Operation, Service, And Troubleshooting

Also see for AQUASNAP 30RAP010-150: Start up & operation manual Installation instructions Installation instructions Controls, start-up, operation, service, and troubleshooting

Carrier AQUASNAP 30RAP010-150 Controls, Start-up, Operation, Service, And Troubleshooting Manual pdf 37 page image

37Refer to Table 13 for dual chiller configuration. In thisexample the master chiller will be configured at address 1 andthe slave chiller at address 2. The master and slave chillersmust reside on the same CCN bus (ConfigurationCCNCCNB) but cannot have the same CCN address (Configu-rationCCNCCNA). Both master and slave chillers musthave Lead/Lag Chiller Enable (ConfigurationRSETLLEN) configured to ENBL. Master/Slave Select (Config-urationRSETMSSL) must be configured to MAST forthe master chiller and SLVE for the slave. Also in this example,the master chiller will be configured to use Lead/Lag BalanceSelect (ConfigurationRSETLLBL) and Lead/Lag Bal-ance Delta (ConfigurationRSETLLBD) to even out thechiller run-times weekly. The Lag Start Delay (Configura-tionRSETLLDY) feature will be set to 10 minutes. Thiswill prevent the lag chiller from starting until the lead chillerhas been at 100% capacity for the length of the delay time. Par-allel configuration (ConfigurationRSETPARA) canonly be configured to YES. The variables LLBL, LLBD andLLDY are not used by the slave chiller.Dual chiller start/stop control is determined by configura-tion of Control Method (ConfigurationOPT1CTRL) ofthe Master chiller. The Slave chiller should always be config-ured for CTRL=0 (Switch). If the chillers are to be controlledby Remote Contacts, both Master and Slave chillers should beenabled together. Two separate relays or one relay withtwo sets of contacts may control the chillers. The Enable/Off/Remote Contact switch should be in the Remote Contactposition on both the Master and Slave chillers. The Enable/Off/Remote Contact switch should be in the Enable position forCTRL=2 (Occupancy) or CTRL=3 (CCN Control).Both chillers will stop if the Master chiller Enable/Off/Remote Contact switch is in the Off position. If the EmergencyStop switch is turned off or an alarm is generated on the Masterchiller the Slave chiller will operate in a Stand-Alone mode.If the Emergency Stop switch is turned off or an alarm isgenerated on the Slave chiller the Master chiller will operate ina Stand-Alone mode.The master chiller controls the slave chiller by changing itsControl Mode (Run StatusVIEWSTAT) and its operat-ing setpoint or Control Point (Run StatusVIEWCT.PT).Temperature Reset — The control system is capable ofhandling leaving-fluid temperature reset based on return coolerfluid temperature. Because the change in temperature throughthe cooler is a measure of the building load, the return tempera-ture reset is in effect an average building load reset method.The control system is also capable of temperature reset basedon outdoor-air temperature (OAT), space temperature (SPT), orfrom an externally powered 4 to 20 mA signal. Accessory sen-sors must be used for SPT reset (33ZCT55SPT). The energymanagement module (EMM) must be used for temperaturereset using a 4 to 20 mA signal. See Tables 15 and 16.MASTERCHILLERSLAVECHILLERLEAVINGFLUIDRETURNFLUIDTHERMISTORWIRING*INSTALL DUAL CHILLER LWTLEAVING FLUID TEMPERATURETHERMISTOR (T10) HERE*Depending on piping sizes, use either:• HH79NZ014 sensor/10HB50106801 well (3-in. sensor/well)• HH79NZ029 sensor/10HB50106802 well (4-in. sensor/well)Fig. 23 — Dual Chiller Thermistor LocationAB1/4 N.P.T.0.505/0.4950.61DIA6” MINIMUMCLEARANCE FORTHERMISTORREMOVALFig. 24 — Dual Leaving Water Thermistor WellPARTNUMBERDIMENSIONS in. (mm)A B10HB50106801 3.10 (78.7) 1.55 (39.4)10HB50106802 4.10 (104.1) 1.28 (32.5)IMPORTANT: Care should be taken when interfacing withother control systems due to possible power supply differ-ences: full wave bridge versus half wave rectification. Con-nection of control devices with different power suppliesmay result in permanent damage. ComfortLink controlsincorporate power supplies with half wave rectification. Asignal isolation device should be utilized if the signal gen-erator incorporates a full wave bridge rectifier.