Carrier 48/50HC04-28 Controls, Start-up, Operation And Troubleshooting

Also see for 50HCQ04---12: Controls, Start-Up, Operation and Troubleshooting Instructions Service and maintenance instructions

Carrier 48/50HC04-28 Controls, Start-up, Operation And Troubleshooting Manual pdf 20 page image

20Number of Heat Stages – Indicates how many heatstages are available for use. See configuration inAppendix A for details on specific unit configuration.Factory Default = 1 for single heat stage units2 for dual stage units0 for cooling only unitsContinuous Occupied Exhaust – This point tells thecontroller when to run the power exhaust if equipped onthe unit.If set to YES, the power exhaust will be on all the timewhen in occupied mode and will be off when inunoccupied mode. If set to NO the power exhaust will becontrolled by the Power Exhaust Setpoint.Default = NORH Control -- Enables dehumidification control if an RHsensor is available and the unit has the Humidi--MiZerRdehumidification option installed.Range = Disable/EnableDefault = Disable(Enabled with Humidi--MiZer option)DCV Control -- Enables demand controlled ventilation(DCV) if valid CO2 sensor value is available and the unithas an economizer installed.Range = Disable/EnableDefault = DisableSystem Space Temperature -- The network spacetemperature value that the controller is using for control(if applicable).Range = N/A Default = --999.0_FSystem Space RH -- The network relative humidity valuethat the controller is using for control (if applicable)Range = N/A Default = --999.0%System Space AQ -- The network indoor air quality (CO2 )value that the controller is using for control (if applicable)Range = N/A Default = --999.0 PPMSystem Cool Demand Level -- The system cool demandlevel being received over the networkRange = N/A Default = 0--3System Heat Demand Level -- The system heat demandlevel being received over the networkRange = N/A Default = --0--3System Outdoor Air Temperature -- Allows the outdoorair temperature value to be network readable whenenabled. Requires RTU Open to be equipped with anoutdoor air temperature sensorRange = N/A Default = --999.0_FSystem Outdoor AQ -- Allows network readable value ofOAQ for calculation during differential OAQ CO2 levelsand IAQ CO2 levels to drive the IAQ controlRange = N/A Default = --999.0 PPMSystem Fire / Smoke -- Allows network readable fire/smokesignal to invoke shutdown action in the RTURange = N/A Default = OFFIndoor CO 2 Sensor Value @ Min mA – Sets the indoorCO2 value when the board reads 4 mA at input 1 or 2.Range = 0 to 9999 ppm Default = 0 ppmIndoor CO 2 Sensor Value @ Max mA – Sets the indoorCO2 value when the board reads 20 mA at input 1 or 2.Range = 0 to 9999 ppm Default = 2000 ppmOutdoor CO2 Sensor Value @ Min mA – Sets the outdoorCO2 value when the board reads 4 mA at input 1 or 2.Range = 0 to 9999 ppm Default = 0 ppmOutdoor CO2 Sensor Value @ Max mA – Sets the outdoorCO2 value when the board reads 20 mA at input 1 or 2.Range = 0 to 9999 ppm Default = 2000 ppmNOTE: The indoor and outdoor min and max mA settingare used to set the linear curve of mA vs. PPM.OPERATIONThe RTU Open will control the compressors, economizerand heating outputs based on its space temperature inputand setpoints. It can also be controlled by a buildingcontrol system or zoning system. An optional CO2 IAQsensor mounted in the space can influence the economizerminimum position. The RTU Open has a hardware clockthat can allow scheduling for stand-alone operation. TheRTU Open’s default is to control to occupied setpoints allthe time, until a type of occupancy control is set. Thefollowing sections describe the operation for the functionsof the RTU Open.OccupancyOccupancy is the fundamental overall control ofequipment. The unit can be in one of two states: Occupiedor Unoccupied. These are usually referred to as periodsbecause they represent periods of any given day. BeforeRTU Open can operate specific functions of theequipment it is installed on, occupancy must bedetermined. There are four different ways RTU Open candetermine occupancy. These are described below andselected by the configuration point Occupancy Source.Always Occupied (Default)The unit will not determine occupancy and continuouslyrun in the occupied state or period. RTU Open ships fromthe factory with this setting to allow immediate operation.BACnetR ScheduleWhen Occupancy Source is set to BACnet Schedule, RTUOpen will use a schedule to change occupancy based upona day of week and a time period. Local time and dateshould be set in the RTU Open for this function to operateproperly. This function applies if setting a local schedulein the RTU Open or if applying the unit to an i--VuR OpenBuilding Automation System or an Open zoning system.An Open network schedule can override a local schedulewithin the unit. A space sensor push button override isonly available when running a local or Open schedule.The push button will override an unoccupied period tooccupied for the specified time duration.BAS On/OffWhen Occupancy Source is set to BAS On/Off, RTUOpen follows occupancy based on an On/Off command tothe BAS ON/OFF software point. An on command setsthe occupancy to occupied, and an off command sets it tounoccupied. The Building Automation System can bespeaking BACnet, Modbus, N2, or LON and is writing tothe BAS On/Off point in the open protocol point map.Remote Occ InputWhen Occupancy Source is set to Remote Occ Input, RTUOpen follows occupancy based on the remote occupancy48 ---50LHTCQ ---01T