Trane Zone Controller, N512 Electric heat operation, Baseboard heat operation, Dehumidification

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Electric heat operation

Electric heat operation

The Tracer ZN521 supports both single-stage and two-stage electric heat. Electric heat is cycled on and off to maintain the discharge air tempera- ture at the active heating setpoint. Two-pipe changeover units with elec- tric heat use the electric heat only when hot water is not available. The use of both electric and hydronic heat is not supported.

Baseboard heat operation

When configured for baseboard heat output, the controller turns on base- board heat at 2.2°F (1.2°C) below the active heating setpoint, and turns off baseboard heat at 0.8°F (0.4°C) below the active heating setpoint. The range for activating the baseboard heat cannot be adjusted; however, the heating setpoint is configurable using the Rover service tool.

Baseboard heating is used most effectively when the discharge air tem- perature control high limit is set below 100°F (56°C). If this is done, the unit heat will maintain the temperature on light load days and the base- board heat will be enabled to maintain the temperature on heavier load days.

Dehumidification

The Tracer ZN521 supports a dehumidification feature. Dehumidification is possible if the following are present:

Mechanical cooling is available

The heating capacity is located in the reheat position

A zone humidity sensor is connected at AI4, or a relative humidity (RH) value is transmitted to the controller by a BAS.

The Space RH Setpoint is valid (configurable using the Rover service tool)

Dehumidification is enabled using the Rover service tool

The controller initiates dehumidification if the zone humidity exceeds the humidity setpoint. The controller continues to dehumidify until the sensed humidity falls below the setpoint minus the relative humidity off- set.

The controller uses cooling and heating capacities simultaneously to dehumidify the space. While dehumidifying, the controller maintains the zone temperature at the active setpoint.

Note:

Dehumidification is not available for face-and-bypass applica- tions, and cannot be used if the unit is in the unoccupied mode. Dehumidification disables the economizing function.

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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 Product description Overview and specificationsDimensions Storage environmentClearances Plastic-cover model dimensions and clearances Additional components Agency listing/complianceDamper actuators Tracer zone temperature sensor optionsZone humidity sensor CO2 sensorOverview and specifications AC-power wiring Input/output terminal wiringGeneral wiring information Communication-link wiring and addressing General wiring information Operating environment requirements Location recommendationsMounting the Tracer ZN521 zone controller Mounting recommendationsApplication SpeedfanMultiple Dehumidification Typical applications for the Tracer ZN521 zone controllerControlValve Economizing HeatElectricBinary inputs BI1 Low-coil-temperature detectionBI2 Condensate overflow Binary inputsBI4 Fan status BI3 Occupancy or generic binary inputAnalog inputs ZN Zone temperatureGND Ground terminals Analog inputsFAN Fan mode input AI1 Entering water temperatureSET Local setpoint AI3 Outdoor air temperature or generic temperature AI2 Discharge air temperatureAI4 configuration options and associated measurement ranges Configuration Measurement rangeAI4 Universal 4-20 mA AI4 terminal wiring CO2 measurement Generic binary output Binary outputsBinary output functions Binary output FunctionsOverriding binary outputs Wiring requirements and optionsRequired 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 Random start Power-up sequenceUnoccupied mode Occupied modeOccupied standby mode Occupancy modesTimed override control Occupied bypass modeZone temperature control Cascade zone controlSimplified zone control Discharge air tempering Heating or cooling modeMorning warm-up Morning cool-downFan operation Entering water temperature sampling functionExhaust control Exhaust controlModulating valve operation Valve operationModulating valve calibration Valve control optionsTwo-position valve operation Modulating outdoor/return air dampersIsolation-valve operation Two-pipe operationModulating outdoor air damper position Ashrae Cycle 1 conformance Ashrae Cycle 2 conformanceEconomizing free cooling Face-and-bypass damper operation Two-position control of a modulating outdoor air damperDX cooling operation Face-and-bypass, isolation-valve operationElectric heat operation Baseboard heat operationDehumidification Unit protection strategies Peer-to-peer communicationLow-coil-temperature protection Smart resetFan off delay Condensate overflowFilter-maintenance timer Freeze protection discharge air temperature low limitFreeze avoidance Tracer ZN521 zone controller circuit board Test buttonManual output test Output For nonClose damper, air Outdoor Open damper, air Outdoor BOP1 BOP2 BOP3 BOP4 BOP5 BOP6 BOP7 BOP8 BOP9 Step ResultRed LED Service indicator Service pin buttonInterpreting LEDs LED activity ExplanationYellow LED Communications indicator Green LED Status indicatorTypes of diagnostics DiagnosticsDiagnostics Table of diagnosticsDiagnostic Probable cause Consequences Type Fan unaffectedPosition Valved unaffectedDamper unaffected Status indicators for operation and communication Probable cause Explanation Fan does not energizeValves remain closed TroubleshootingDX or electric heat does not energize Valves remain openOutdoor air damper remains open Outdoor air damper remains closedOutdoor air damper remains open Troubleshooting Numerics IndexIndex Index Index Page Trane