Linkage - Carrier RTU Open v5 Installation And Startup Manual

Supply Fan Runtime - The RTU Open generates a this alarm when the accumulated runtime exceeds the Unit
Configuration > Supply Fan Service Alarm Timer value (when not set to 0). This alarm is most commonly used to
indicate an equipment maintenance interval is due. The supply fan runtime accumulator may be reset by setting
the Maintenance > Reset Supply Fan Runtime Alarm to Clear, and then back to Run – acknowledging each
selection by clicking the OK button when it appears. Setting Unit Configuration > Supply Fan Service Timer value
to 0 disables the supply fan runtime alarm function.
Compressor 1 Runtime - The RTU Open generates this alarm when the accumulated runtime exceeds the Unit
Configuration > Compressor 1 Service Alarm Timer value (when not set to 0). This alarm is most commonly used
to indicate an equipment maintenance interval is due. The Compressor 1 Runtime accumulator may be reset by
setting the Maintenance > Reset Comp 1 Runtime Alarm to Clear, and then back to Run – acknowledging each
selection by clicking the OK button when it appears. Setting Unit Configuration > Compressor 1 Service Timer
value to 0 disables the Compressor 1 Runtime alarm function.
Compressor 2 Runtime - The RTU Open generates this alarm when the accumulated runtime exceeds the Unit
Configuration > Compressor 2 Service Alarm Timer value (when not set to 0). This alarm is most commonly used
to indicate an equipment maintenance interval is due. The Compressor 2 runtime accumulator may be reset by
setting the Maintenance > Reset Comp 2 Runtime Alarm to Clear, and then back to Run – acknowledging each
selection by clicking the OK button when it appears. Setting Unit Configuration > Compressor 2 Service Timer
value to 0 disables the Compressor 2 runtime alarm function. Note that this function is unavailable if the Service
Configuration > Compressor States value is not set to Two Stages.
Airside Linkage Alarm - An RTU Open may act as an air source in a zoned system. Carrier systems use a function
called Linkage™ to pass data between a master zone and its air source over an MS/TP network connection. When
the RTU Open is part of a linked system, it will indicate an airside linkage alarm if it loses communications with its
linkage master or if it receives data from more than 1 master zone.

Linkage

The RTU Open may serve as an air source to an Open Variable Volume Terminal (VVT) system. When the RTU Open
is part of a VVT system and the controllers are wired together to form a network, the controllers may use a method
of communication known as Linkage™. Linkage is a method by which an air source and its subordinate zone
terminals exchange data to form a coordinated HVAC system. The system's air source controller, zone controllers,
and bypass controller are linked so that their data exchange can be managed by one zone controller configured as
the VVT Master.
The VVT Master gathers the following information from the slave zone controllers:
• occupancy status
•
setpoints
•
zone temperature
• relative humidity
• CO level
2
•
damper position
•
optimal start data
The VVT Master performs mathematical calculations and algorithms on the data and then sends the composite
information to the air source. The VVT Master receives information from the air source such as System Mode,
Supply Air Temperature, and Outside Air Temperature (if available), and passes that information to all linked
controllers.
RTU Open v5
Installation and Start-up Guide
59
Sequence of Operation
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