Carrier 48LC 04 Controls, Start-up, Operation And Troubleshooting

Also see for 48LC 05: Controls, Start-Up, Operation and Troubleshooting Service and maintenance instructions Service and maintenance instructions

Carrier 48LC 04 Controls, Start-up, Operation And Troubleshooting Manual pdf 25 page image

25II.FN = 2 (Always)The indoor fan operation for II.FN =2 is the same as the operationwhen IA.FN =1, except the algorithm is not limited to the occupiedperiods only. The fan can be triggered on when the space isoccupied or unoccupied.Temperature Compensated StartThis logic is used when the unit is in the unoccupied state. Thecontrol will calculate early Start Bias time based on SpaceTemperature deviation from the occupied cooling and heating setpoints. This will allow the control to start the unit so that the spaceis at conditioned levels when the occupied period starts. This isrequired for ASHRAE 90.1 compliance. A space sensor is requiredfor non-linkage applications.Setting Up the SystemThe settings for temperature compensated start can be found in thelocal display under ConfigurationUNIT.ITEM EXPANSION RANGE UNITS CCN POINTTCS.C Temp.Cmp.Strt.Cool Factr 0 - 60 min TCSTCOOLTCS.H Temp.Cmp.Strt.Heat Factr 0 - 60 min TCSTHEATTemp Comp Strt Cool Factr (TCS.C)This is the factor for the start time bias equation for cooling.Temp Comp Strt Heat Factr (TCS.H)This is the factor for the start time bias equation for heating.NOTE: Temperature compensated start is disabled when thesefactors are set to 0.Temperature Compensated Start LogicThe following conditions must be met for the algorithm to run:S Unit is in unoccupied state.S Next occupied time is valid.S Current time of day is valid.S Valid space temperature reading is available (sensor or CCNnetwork).The algorithm will calculate a Start Bias time in minutes using thefollowing equations:If (space temperature > occupied cooling set point)Start Bias Time = (space temperature – occupied cooling setpoint)* TCS.CIf (space temperature < occupied heating set point)Start Bias Time = (occupied heating set point – spacetemperature)*TCS.HWhen the Start Bias Time is greater than zero the algorithm willsubtract it from the next occupied time to calculate the new starttime. When the new start time is reached, the TemperatureCompensated Start mode is set, the fan is started and the unitcontrolled as in an occupied state. Once set, TemperatureCompensated mode will stay on until the unit goes into theOccupied mode. The Start Bias Time will be written into the CCNLinkage Equipment Table if the unit is controlled in DAV mode. Ifthe Unoccupied Economizer Free Cool mode is active whentemperature compensated start begins, the Unoccupied Free Coolmode will be stopped.NOTE: The maximum minutes Start Bias can be is 180.Carrier Comfort Network (CCN)R ConfigurationIt is possible to configure the ComfortLink control to participate asan element of the Carrier Comfort Network (CCN) system directlyfrom the local display. This section will deal with explaining thevarious programmable options which are found under the CCNsub-menu in the Configuration mode.The major configurations for CCN programming are located in thelocal displays at ConfigurationCCN. See Appendix A.CCN Address (CCN.A)This configuration is the CCN address the rooftop is assigned.CCN Address (CCN.B)This configuration is the CCN bus the rooftop is assigned.CCN Baud Rate (BAUD)This configuration is the CCN baud rate.CCN Time/Date Broadcast (BRODB.TIM)If this configuration is set to ON, the control will periodically sendthe time and date out onto the CCN bus once a minute. If thisdevice is on a CCN network then it will be important to make surethat only one device on the bus has this configuration set to ON. Ifmore than one time broadcaster is present, problems with the timewill occur.NOTE: Only the time and date broadcaster can performdaylight savings time adjustments. Even if the rooftop is standalone, the user may want to set this to ON to accomplish thedaylight/savings function.CCN OAT Broadcast (BRODB.OAT)If this configuration is set to ON, the control will periodicallybroadcast its outside-air temperature at a rate of once every 30minutes.Global Schedule Broadcast (BRODB.GS)If this configuration is set to ON and the schedule number(SCH.N) is between 65 and 99, then the control will broadcast theinternal time schedule once every 2 minutes.CCN Broadcast Acknowledger (BRODB.ACK)If this configuration is set to ON, then when any broadcasting isdone on the bus, this device will respond to and acknowledge.Only one device per bus can be configured for this option.Schedule Number (SCH.OSCH.N)This configuration determines what schedule the control mayfollow.SCH.N = 0 The control is always occupied.SCH.N = 1 The control follows its internaltime schedules. The user mayenter any number between 1and 64 but it will be overwrittento “1” by the control as it onlyhas one internal schedule.SCH.N = 65---99 The control is either set up toreceive to a broadcasted timeschedule set to this number orthe control is set up tobroadcast its internal timeschedule (B.GS) to the networkand this is the global schedulenumber it is broadcasting. If thisis the case, then the control stillfollows its internal timeschedules.Accept Global Holidays? (SCH.OHOL.G)If a device is broadcasting the time on the bus, it is possible to accept thetime yet not accept the global holiday from the broadcast message.Override Time Limit (SCH.OOV.TL)This configuration allows the user to decide how long an overrideoccurs when it is initiated. The override may be configured from 1to 4 hours. If the time is set to 0, the override function willbecome disabled.Timed Override Hours (SCH.OOV.EX)This displays the current number of hours left in an override. It ispossible to cancel an override in progress by writing “0” to thisvariable, thereby removing the override time left.48/50LC