Trane N512, CNT-SVX07C-EN Occupancy modes, Occupied mode, Unoccupied mode, Occupied standby mode

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Chapter 5 Sequence of operations

Occupancy modes

Occupancy modes can be controlled by any of the following:

•The state of the local (hard-wired) occupancy binary input BI3 (see “BI3: Occupancy or generic binary input” on page 15)

•A timed override request from a Trane zone sensor (see “Timed over- ride control” on page 37)

•A communicated signal from a peer device (see “Peer-to-peer commu- nication” on page 48)

•A communicated signal from a BAS

A communicated request, either from a BAS or a peer controller, takes precedence over local requests. If a communicated occupancy request has been established and is no longer present, the controller reverts to the default (occupied) occupancy mode after 15 minutes (if no hard-wired occupancy request exists). The Tracer ZN521 has the following occupancy mode options:

•Occupied

•Unoccupied

•Occupied standby

•Occupied bypass

Occupied mode

In occupied mode, the controller maintains the zone temperature based on the occupied heating or cooling setpoints. The controller uses the occu- pied mode as a default mode when other forms of occupancy request are not present. The fan will run as configured (continuous or cycling). The outdoor air damper will close when the fan is off. The temperature set- points can be local (hard-wired), communicated, or stored default values (configurable using the Rover service tool).

Unoccupied mode

In unoccupied mode, the controller attempts to maintain the zone temper- ature based on the unoccupied heating or cooling setpoint. The fan will cycle between high speed and off. The outdoor air damper will remain closed, unless economizing. The controller always uses the stored default setpoint values (configurable using the Rover service tool), regardless of the presence of a hard-wired or communicated setpoint value.

Occupied standby mode

The controller is placed in occupied standby mode only when a communi- cated occupied request is combined with an unoccupied request from occupancy binary input BI3. In occupied standby mode, the controller maintains the zone temperature based on the occupied standby heating or cooling setpoints. Because the occupied standby setpoints are typically spread 2°F (1.1°C) in either direction and the outdoor air damper is closed, this mode reduces the demand for heating and cooling the space.

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Contents Installation and Operation Tracer ZN521 Zone Controller Page CNT-SVX07C-EN April CNT-SVX07C-EN Tracer ZN521 Zone Controller Installation and Operation CNT-SVX07C-EN Contents Sequence of operations Status indicators for operation and communication Troubleshooting Index Overview and specifications Product descriptionStorage environment DimensionsClearances Plastic-cover model dimensions and clearances Agency listing/compliance Additional componentsZone humidity sensor Tracer zone temperature sensor optionsDamper actuators CO2 sensorOverview and specifications Input/output terminal wiring AC-power wiringGeneral wiring information Communication-link wiring and addressing General wiring information Location recommendations Operating environment requirementsMounting recommendations Mounting the Tracer ZN521 zone controllerControlValve Economizing Typical applications for the Tracer ZN521 zone controllerApplication SpeedfanMultiple Dehumidification HeatElectricBI2 Condensate overflow BI1 Low-coil-temperature detectionBinary inputs Binary inputsBI3 Occupancy or generic binary input BI4 Fan statusGND Ground terminals ZN Zone temperatureAnalog inputs Analog inputsAI1 Entering water temperature FAN Fan mode inputSET Local setpoint AI2 Discharge air temperature AI3 Outdoor air temperature or generic temperatureConfiguration Measurement range AI4 configuration options and associated measurement rangesAI4 Universal 4-20 mA AI4 terminal wiring CO2 measurement Binary output functions Binary outputsGeneric binary output Binary output FunctionsRequired controller inputs for proper operation Wiring requirements and optionsOverriding binary outputs Function Input source For more information SeeTwo-pipe hydronic-cooling unit Two-pipe hydronic-heating unit Two-pipe hydronic heating/cooling unit with auto changeover Four-pipe hydronic heating/cooling unit Four-pipe heating/cooling unit with auto changeover Two-pipe heating unit with DX cooling Electric heat unit with DX cooling Electric heat unit Two-pipe heating unit with face-and-bypass damper Two-pipe heating/cooling unit with face-and-bypass damper Four-pipe heating/cooling unit with face-and-bypass damper Input/output functions and wiring for typical applications Power-up sequence Random startOccupied standby mode Occupied modeUnoccupied mode Occupancy modesOccupied bypass mode Timed override controlCascade zone control Zone temperature controlSimplified zone control Morning warm-up Heating or cooling modeDischarge air tempering Morning cool-downEntering water temperature sampling function Fan operationExhaust control Exhaust controlModulating valve calibration Valve operationModulating valve operation Valve control optionsIsolation-valve operation Modulating outdoor/return air dampersTwo-position valve operation Two-pipe operationModulating outdoor air damper position Ashrae Cycle 2 conformance Ashrae Cycle 1 conformanceEconomizing free cooling DX cooling operation Two-position control of a modulating outdoor air damperFace-and-bypass damper operation Face-and-bypass, isolation-valve operationBaseboard heat operation Electric heat operationDehumidification Peer-to-peer communication Unit protection strategiesFan off delay Smart resetLow-coil-temperature protection Condensate overflowFreeze protection discharge air temperature low limit Filter-maintenance timerFreeze avoidance Test button Tracer ZN521 zone controller circuit boardManual output test For non OutputClose damper, air Outdoor Open damper, air Outdoor Step Result BOP1 BOP2 BOP3 BOP4 BOP5 BOP6 BOP7 BOP8 BOP9Interpreting LEDs Service pin buttonRed LED Service indicator LED activity ExplanationGreen LED Status indicator Yellow LED Communications indicatorDiagnostics Types of diagnosticsDiagnostic Probable cause Consequences Type Table of diagnosticsDiagnostics Fan unaffectedValved unaffected PositionDamper unaffected Status indicators for operation and communication Fan does not energize Probable cause ExplanationTroubleshooting Valves remain closedValves remain open DX or electric heat does not energizeOutdoor air damper remains closed Outdoor air damper remains openOutdoor air damper remains open Troubleshooting Index NumericsIndex Index Index Page Trane