Carrier TruVu VAVB3-E2 Installation And Startup Manual page 75

The VAV Master then does the following calculations and sends the results to the air source.
•
If any zone is occupied, the system's occupancy status is set to occupied.
•
If the system is occupied, it averages the space temperatures from all occupied zones using their normal
terminal size at 1" (.249 kpa) VP to apply a weighting factor to that average (OCCSPT).
•
It performs this same weighted average space temperature calculation for all the zones in the system (SPT).
•
If no zone is occupied, it sets the occupied space temperature to "?". ("?" only displays on the Details tab of
the Collector microblock and the Linkage status section of the Properties page.)
•
It calculates 4 weighted average setpoints:
•
the occupied heating weighted average setpoint (OHSP)
•
occupied cooling weighted average setpoint (OCSP)
•
the weighted average unoccupied heating setpoint (UHSP)
•
unoccupied cooling setpoint (UCSP).
•
If the zones supply CO
configuration for each.
The air source determines its operating mode from the information received, and then sends the following to the
Master:
•
Air source mode
•
Supply air temperature
•
Outside air temperature
•
Static pressure (if applicable)
The air source verifies the mode by comparing its supply air temperature to the space temperature received
through linkage. See the air source documentation for operation and parameters used to verify its mode. This
verification allows the system to verify that the stated air source mode is actually being provided. For example, if
the air source heat has failed, the air source's actual mode would not indicate heat unless that mode was verified
by the equipment's supply air temperature.
The VAV Master continuously evaluates all zones and processes their data as described above. The system
switches modes only if the equipment mode changes.
VVT Systems
A VVT Master determines system operation by prioritizing heating and cooling requirements from all the zones
based on their occupancy, demand, and damper size.
The VVT Master continuously scans the system to determine if any zones are occupied. If any zones are occupied,
the VVT Master evaluates the occupied zones' heating or cooling demands to determine the following:
•
The system mode. The mode is:
Cooling if the number of occupied zones with cooling demands exceeds the number of occupied zones
○
with heating demands, and the demand is greater than or equal to the number of configured Linkage
Callers.
Heating if the number of occupied zones with a heating demand exceeds or is equal to the number of
○
Linkage Callers.
•
The reference zone, the zone with the greatest demand for the system mode
If no zones are occupied or no occupied zones require heating or cooling, the VVT Master performs the evaluation
described above for the unoccupied zones.
TruVu™ VAVB3-E2
Installation and Start-up Guide
or RH values, it calculates either a maximum or average value as determined by the
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Start-up
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