Trane Tracer Unit Ventilator, ZN.520 manual Output Overrides

Page 51

Unit Operation

than or equal to the configurable exhaust enable setpoint. This is useful for exhaust fans designed to offset the added economizer ventilation.

The exhaust fan is disabled when the outdoor air damper position drops 10% below the exhaust en- able point. If the exhaust fan en- able setpoint is less than 10%, the Tracer ZN.520 controller energizes the exhaust fan at the enable point and disables it when the outdoor air damper closes.

Output Overrides

Manual Output Test

Manual output test allows the bi- nary outputs to be energized in a predefined sequence.(For more in- formation see, Manual Output

Test, on page 48 for more informa- tion.)

Water Valve Override

To enable quicker water balanc- ing, the controller allows a user to specify the desired state of all wa- ter valves. The values supported are:

qOpen all valves

qClose all valves

The valves in the system will re- main open for two hours or until normal operation is resumed.

The Tracer Summit or the Rover service tool is required to access this feature.

Fan Status

There are two ways to do fan sta- tus monitoring:

1.The status of the fan is reported based on the state of the binary output(s) dedicated to fan control. The fan status is reported as HIGH or LOW whenever the corresponding binary output is directed ON.

The fan status is reported as OFF when none of the fan out- puts are directed ON.

2.The Tracer ZN.520 controller has a binary input available for a fan status device (current sensing relay or differential pressure switch) which can provide feedback of fan opera- tion. If the device does not indicate fan operation after 1

minute, a unit shutdown is ini- tiated, and the unit is latched

OFF.

Filter Status/ Maintenance Timer

The unit filter status\maintenance timer is based on the cumulative run hours of the unit fan. The con- troller compares the fan run time against an adjustable fan run hour limit and recommends unit main- tenance as required.

The Rover service tool is used to edit the maintenance required set- point time. Once the setpoint limit is exceeded, the controller gener-

ates a MAINTENANCE REQUIRED infor-

mational diagnostic. When the maintenance required setpoint time is set to zero, the controller disables this feature.

You can use the Trace Summit or the Rover service tool to clear the

MAINTENANCE REQUIRED informa-

tional diagnostic. Once the diag- nostic is cleared, the controller resets the fan run time to zero and begins accumulating fan run hours again.

Note: If at any time the unit loses power, the timer is reset to zero.

Other Modes

DEHUMIDIFICATION

Note: If the unit is in the unoccupied mode, the dehumidification routine will not operate

Dehumidification is possible when mechanical cooling is available; the heating capacity is in the re- heat position; and the space rela- tive humidity setpoint is valid.

The controller starts dehumidify- ing the space when the space hu- midity exceeds the humidity setpoint. The controller continues to dehumidify until the sensed hu- midity falls below the setpoint mi- nus the relative humidity offset.

The controller uses the cooling and reheat coils simultaneously to dehumidify the space. When de- humidifying, the discharge air temperature is controlled to main- tain the space temperature at the current setpoint.

Economizing is disabled during the dehumidification mode.

Note: While in the dehumidification mode, if there is a call for capacity by the unit, the zone temperature setpoint will take priority over the relative humidity setpoints.

DEFROST

For defrost operation, a sensor is wired in series with the DX cooling relay. When a defrost condition is detected, the condensing unit is disabled, and the unit is placed in the DEFROST mode.

During DEFROST the condensing unit is OFF the outside air damper is set to the minimum positions, and the fan will continue to oper- ate as continuous. The unit will re- main in the DEFROST mode until the senor resets at 48°F. The unit will return to NORMAL operation af- ter the mode is discontinued.

FREEZE AVOIDANCE

FREEZE AVOIDANCE is used as low

ambient temperature protection, and is only invoked when the fan is OFF. This includes the UNOCCUPIED mode when there is no call for ca- pacity, or any other time the fan is

UV-SVP01A-EN

45

Page 50 Page 52
Image 51
Page 50 Page 52
Contents Tracer ZN.520 for Classroom Unit Ventilator Installation Owner DiagnosticsInstallation of New Units Start-up ProceduresPower Up Sequence Tracer ZN.520 Overview General InformationGeneral Information Tracer ZN.520 unit controller circuit board Controller Circuit Board FeaturesController Features ServiceTypical Components Communication Configurations Peer-to-Peer CommunicationsIntegrated Comfort System Stand-Alone Communication InterfaceInteroperability Description End Device SpecificationsCharacteristic Standard End DevicesStandard End Devices Way Control Valve Time clock Zone sensor Dpdt Control Transformer Specifications Installation and WiringBinary Inputs Generic/baseboard Heat Binary Output Binary OutputsAnalog inputs Analog InputsMounting Vertical classroom unit ventilator end pocket Power WiringProper zone sensor placement Installing the Wall- Mounted Zone Sensor OptionalHumidity and CO2 Sensors Typical Wiring Diagram-Wall Mounted Zone Sensor Typical Wiring Diagram-Unit Mounted Zone Sensor Typical Wiring Diagram-Unit Input and output summary Input/Output SummaryInput/Output Summary Heating source ConfigurationConfigurable parameters Cooling sourceBinary Outputs1 Analog input summary Binary input summary ConfigurationBinary Inputs1 Analog Inputs1Default Fan ConfigurationEnd Device Configurations Fan configuration rangesDischarge Air Limits Setpoint defaults Default Valid rangeDischarge air limit ranges Default Valid range SetpointsOccupied Bypass Timer Power-Up Control WaitMaintenance Timers Location Identifier Unit Identification TagWinking Occupancy Power-UpUnit Operation Heating And Cooling Changeover LogicHeat/Cool Changeover logic Fan Operation Fan Off DelayCooling Operation Heating OperationModulating Valves Valve OperationFace-and-Bypass Damper Operation Exhaust fan/damper operationTemperature Assumed1 Entering Water Temperature SamplingWater assumption chart Unit ConfigurationBaseboard Heat Operation Economizer OperationDX Operation Electric Heat OperationOther Modes Filter Status/ Maintenance TimerOutput Overrides Fan StatusSimple data sharing application Data Sharing-LonWorksMore complex data sharing application Heating And Cooling Changeover Logic Heat/Cool Changeover logic Cooling Operation Valve Operation Entering Water Temperature Sampling Economizer Operation Output Overrides Data Sharing-LonWorks More complex data sharing application Yellow Comm LED TroubleshootingRed Service LED Black Service Push ButtonExit6 Test ProcedureTroubleshooting Outdoor Air Temperature Failure Space Temperature FailureEntering Water Temperature Failure Discharge Air Temperature LimitDiagnostics Troubleshooting Translating Multiple Diagnostics Fans Rover service toolValves Valves stay closed Probable cause Possible ExplanationValves stay open Probable cause Possible Explanation DX/Electric Heat Outside Air DamperOutdoor air damper stays closed Probable cause Explanation Probable Cause Explanation Outdoor air damper stays openReplacing Circuit Boards Tracer ZN.520 Unit Controller ReplacementAppendix Hardwired Setpoint AdjustmentFan Switch Resistance Values Hardwired Thermistor ValuesFunction Appendix-Binary ConfigurationBinary Configuration Binary configuration details Binary input or outputUnit Operation Based On The Effective HEAT/COOL Output Heat/cool mode input NviHeatCoolEffective heat/ cool mode output nvoHeatCool Appendix-Unit OperationAppendix-Unit Operation Input/output listing1 Configuration properties1Appendix-Data Lists Data ListsSet the Program Setting the Time ClockAppendix-Timeclock Set the Time and DayOverride Program Manual Operation Review and Change ProgramsAppendix-Timeclock Appendix-Location Identifier Location Identifier Location Identifier Location Identifier Trane Company
Top Page Image Contents