Trane N512 AI2 Discharge air temperature, AI3 Outdoor air temperature or generic temperature

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Chapter 4 Input/output functions and wiring for typical applications

For units not configured as changeover units, the entering water temper- ature value is used for information and troubleshooting only and does not affect the operation of the controller.

Note:

AI1 is not polarity sensitive; you can connect either terminal to either sensor lead.

AI2: Discharge air temperature

The AI2 analog input functions as the local discharge air temperature input.

IMPORTANT

The Tracer ZN521 cannot operate without a valid discharge air tempera- ture value.

The controller receives the temperature as a resistance signal from a

10 kΩ thermistor wired to analog input AI2. The thermistor is typically located downstream from all unit heating and cooling coils at the unit dis- charge area.

If a discharge air temperature value is invalid or is not present, the con- troller generates a Discharge Air Temp Failure diagnostic and shuts down the equipment. When the thermistor returns to a valid tempera- ture, the controller automatically allows the equipment to resume normal operation.

Note:

AI2 is not polarity sensitive; you can connect either terminal to either sensor lead.

AI3: Outdoor air temperature or generic temperature

The AI3 analog input can function as either:

•An outdoor air temperature input

•A generic temperature input

If AI3 is configured as the local (hard-wired) outdoor air temperature input, the controller receives the temperature as a resistance signal from a 10 kΩ thermistor wired to analog input AI3. An outdoor air tempera- ture value communicated by means of a LonTalk link can also be used for controllers operating on a BAS. If both hard-wired and communicated outdoor air temperature values are present, the controller uses the com- municated value. If a valid hard-wired or communicated outdoor air tem- perature value is established and then is no longer present, the controller generates an Outdoor Air Temp Failure diagnostic.

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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 componentsTracer zone temperature sensor options Damper actuatorsZone humidity sensor 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 controllerTypical applications for the Tracer ZN521 zone controller Application SpeedfanMultiple DehumidificationControlValve Economizing HeatElectricBI1 Low-coil-temperature detection Binary inputsBI2 Condensate overflow Binary inputsBI3 Occupancy or generic binary input BI4 Fan statusZN Zone temperature Analog inputsGND Ground terminals 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 outputs Generic binary outputBinary output functions Binary output FunctionsWiring requirements and options Overriding binary outputsRequired controller inputs for proper operation 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 mode Unoccupied modeOccupied standby mode Occupancy modesOccupied bypass mode Timed override controlCascade zone control Zone temperature controlSimplified zone control Heating or cooling mode Discharge air temperingMorning warm-up Morning cool-downEntering water temperature sampling function Fan operationExhaust control Exhaust controlValve operation Modulating valve operationModulating valve calibration Valve control optionsModulating outdoor/return air dampers Two-position valve operationIsolation-valve operation Two-pipe operationModulating outdoor air damper position Ashrae Cycle 2 conformance Ashrae Cycle 1 conformanceEconomizing free cooling Two-position control of a modulating outdoor air damper Face-and-bypass damper operationDX cooling operation Face-and-bypass, isolation-valve operationBaseboard heat operation Electric heat operationDehumidification Peer-to-peer communication Unit protection strategiesSmart reset Low-coil-temperature protectionFan off delay 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 BOP9Service pin button Red LED Service indicatorInterpreting LEDs LED activity ExplanationGreen LED Status indicator Yellow LED Communications indicatorDiagnostics Types of diagnosticsTable of diagnostics DiagnosticsDiagnostic Probable cause Consequences Type 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