Carrier 48TC*D08 RTU-MP Sequence of Operation, Loadshed Command Gas and Electric Heat Units

The PremierLinkt controller will generate a Linkage Communication Failure alarm if a failure occurs for 5 consecutive minutes once a Linkage has previously been established. It will then revert back to its own SPT, setpoints and occupancy schedule for control. For this reason, Carrier strongly recommends that an SPT be installed in the space on open plenum systems or in the return air duct of ducted return air systems to provide continued backup operation. When Linkage communication is restored, the controller will generate a return to normal.

For more information on how the PremierLink controller is used in conjunction with the Carrier 3V control system, contact your CCN controls representative.

IMPORTANT: The PremierLink controller should not be used as a linked air source in a ComfortIDt VAV system. The ComfortID VAV system will NOT function correctly when applied with a PremierLink controller as the air source, resulting in poor comfort control and possible equipment malfunction.

NOTE: The PremierLink controller can be used as an air source in a 3V Pressure Independent (PI) System (a 3V Linkage Coordinator with ComfortID PI Zone Controllers), but it should not be used as an air source with ComfortID controllers unless a 3V zone controller is used as the Linkage Coordinator. Contact your Carrier CCN controls representative for assistance.

Demand Limit — If the demand limit option is enabled, the control will receive and accept Redline Alert and Loadshed commands from the CCN loadshed controller. When a redline alert is received, the control will set the maximum stage of capacity equal to the stage of capacity that the unit is operating at when the redline alert was initiated.

When loadshed command is received the control will reduce capacity as shown in Table 32.

Table 32 – Loadshed Command — Gas and Electric

Heat Units

CURRENT CAPACITY	NEW CAPACITY
CMP1	DX Cooling OFF
CMP1+CMP2	CMP1
HS1	Heat OFF
HS1+HS2 (+HS3)	HS1

The controller will have a maximum demand limit timer of 1 hour that prevents the unit from staying in load shed or redline alert longer than 1 hour in the event the controller loses communication with the network load shed module. Should the maximum demand limit timer expire prior to receiving the loadshed device command from CCN, the control will stop demand limit mode and return to normal operation.

RTU-MP Sequence of Operation

The RTU-MP will control the compressor, economizer and heating outputs based on its own space temperature input and setpoints. An optional CO2 IAQ sensor mounted in the space can influence the economizer minimum position. The RTU-MP has its own hardware clock that is set automatically when the software is installed on the board. The RTU-MP’s default is to control to occupied setpoints all the time, until a type of occupancy control is set. Occupancy types are described in the scheduling section. The following sections describe the operation for the functions of the RTU-MP. All point objects that are referred to in this sequence will be in reference to the objects as viewed in BACview6 Handheld.

Scheduling

Scheduling is used to start heating or cooling (become occupied) based upon a day of week and a time period and control to the occupied heating or cooling setpoints. Scheduling functions are located under occupancy determination and the schedule menu accessed by the Menu softkey (see Appendix - for menu structure). Your local time and date should be set for these functions to operate properly. Five scheduling functions are available by changing the Occupancy Source to one of the following selections:

Always Occupied (Default Occupancy)

The unit will run continuously. RTU-MP ships from the factory with this setting.

Local Schedule

The unit will operate according to the schedule configured and stored in the unit. The local schedule is made up of three hierarchy levels that consist of two Override schedules, twelve Holiday and four Daily schedules, and are only accessible by the BACview screen (handheld or virtual).

The Daily schedule is the lowest schedule in the hierarchy and is overridden by both the Holiday and Override schedule. It consists of a start time, a stop time (both in 24 hour mode) and the seven days of the week, starting with Monday and ending in Sunday. To select a daily schedule scroll to the Schedules menu off of the Menu selection. Enter the User password and change the Occupancy Source to Local Schedule. Scroll down and over to the Daily menu and press enter. Choose one of the four Daily schedules by pressing the Next softkey and change the Use? point from NO to YES by selecting the point and pressing the INCR or DECR softkey. Press the OK softkey and scroll to the start and stop times. Edit these times following the same steps as the Use? point. Finally scroll down to the Days: section and highlight the days required for the Daily schedule by INCR or DECR softkeys and press OK softkey.

48TC

83