Carrier 48TCA04---A12 Service And Maintenance Instructions

79control to the occupied heating or cooling setpoints.Scheduling functions are located under occupancydetermination and the schedule menu accessed by theMenu softkey (see Appendix -- for menu structure). Yourlocal time and date should be set for these functions tooperate properly. Five scheduling functions are availableby changing the Occupancy Source to one of thefollowing selections:Always Occupied (Default Occupancy)The unit will run continuously. RTU--MP ships from thefactory with this setting.Local ScheduleThe unit will operate according to the schedule configuredand stored in the unit. The local schedule is made up ofthree hierarchy levels that consist of two Overrideschedules, twelve Holiday and four Daily schedules, andare only accessible by the BACview screen (handheld orvirtual).The Daily schedule is the lowest schedule in the hierarchyand is overridden by both the Holiday and Overrideschedule. It consists of a start time, a stop time (both in 24hour mode) and the seven days of the week, starting withMonday and ending in Sunday. To select a daily schedulescroll to the Schedules menu off of the Menu selection.Enter the User password and change the OccupancySource to Local Schedule. Scroll down and over to theDaily menu and press enter. Choose one of the four Dailyschedules by pressing the Next softkey and change theUse? point from NO to YES by selecting the point andpressing the INCR or DECR softkey. Press the OK softkeyand scroll to the start and stop times. Edit these timesfollowing the same steps as the Use? point. Finally scrolldown to the Days: section and highlight the days requiredfor the Daily schedule by INCR or DECR softkeys andpress OK softkey.The Holiday schedule is created to override the Dailyschedule and identify a specific day and month of the yearto start and stop the unit and change control to theunoccupied heating and cooling setpoints. Follow thesame steps to turn on one of the twelve Holiday schedulesand start and stop times. Next, select one out of the twelvemonths and one out of the thirty--one days of that month.The RTU--MP will now ignore the Daily schedule for thespecific day and time you selected and follow the HolidaySchedule for this period.The Override schedules primary purpose is to provide atemporary change in the occupied heating and coolingsetpoints and force the unit to control to the unoccupiedheating and cooling setpoints. This would occur on a setday in a particular month and last during the start and stoptime configured. The Override schedule is enabled byfollowing the same steps to create the Holiday schedule.NOTE: Push button override is only available whenrunning a local or BACnet Schedule.BACnet ScheduleFor use with a Building Automation System that supportsnative BACnet scheduling is scheduling the unit. With theOccupancy Source set to BACnet schedule the BAS willcontrol the unit through network communication and it’sown scheduling function.BAS On/OffThe Building Automation System is scheduling the unitvia an On/Off command to the BAS ON/OFF softwarepoint. The Building Automation System can be speakingBACnet, Modbus, or N2 and is writing to the BAS On/Offpoint in the open protocol point map.NOTE: If the BAS supports NATIVE BACnetscheduling, then set the Occupancy Source to BACnetschedule. If the BAS is BACnet but does NOT supportNATIVE BACnet scheduling, then set the OccupancySource to BAS On/Off.DI On/OffA hard--wired input on the RTU--MP will command theunit to start/stop. Inputs 3, 5, 8, and 9 on plug J5 can behard--wired to command the unit to start/stop.NOTE: Scheduling can either be controlled via the unitor the BAS, but NOT both.Indoor FanThe indoor fan will be turned on whenever any one of thefollowing conditions is true:S It is in the occupied mode. This will be determined by itsown internal occupancy schedule.S Whenever there is a demand for cooling or heating in theunoccupied mode.S Whenever the remote occupancy switch is closed duringDI On/Off schedule type or if occupancy is forcedoccupied by the BAS during BAS On/Off schedule type.When transitioning from unoccupied to occupied, therewill be a configured time delay of 5 to 600 seconds beforestarting the fan. The fan will continue to run as long ascompressors, heating stages, or the dehumidificationrelays are on when transitioning from occupied tounoccupied with the exception of Shutdown mode. If FireShutdown, safety chain, SAT alarm or SPT alarm areactive; the fan will be shutdown immediately regardless ofthe occupancy state or demand.The RTU--MP has an optional Supply Fan Status input toprovide proof of airflow. If this is enabled, the point willlook for a contact closure whenever the Supply Fan Relayis on. If it is not enabled then it will always be the samestate as the Supply Fan Relay. The cooling, economizer,heating, dehumidification, CO2 and power exhaustroutines will use this input point for fan status.CoolingThe compressor outputs are controlled by the CoolingControl PID Loop and Cooling Stages Capacity algorithm.They will be used to calculate the desired number ofstages needed to satisfy the space by comparing the SpaceTemperature (SPT) to the Occupied Cool Setpoint plus theT56 slider offset when occupied and the Unoccupied CoolSetpoint (UCSP) plus the T56 slider offset, if unoccupied.The economizer, if available, will be used for cooling inaddition to the compressors. The following conditionsmust be true in order for this algorithm to run:S Indoor Fan has been ON for at least 30 seconds.S Heat mode is not active and the time guard betweenmodes equals zero.S If occupied and the SPT >(occupied cool setpoint plus48TC