Trane ZN.520, Tracer Unit Ventilator Valves stay closed Probable cause Possible Explanation

Page 62

Troubleshooting

Valves

Table 30: Valves stay closed

Probable cause

Possible Explanation

 

 

 

 

Unit wiring

The wiring between the controller outputs and the valve(s) must be present and correct for normal

valve operation.

 

 

 

Random-start observed

After power-up, the controller always observes a random-start from 5 to 30 seconds. The controller

remains off until the random-start time expires.

 

 

 

Unit configuration

The controller must be properly configured based on the actual installed end devices and application.

When the unit configuration does not match the actual end devices, the valves may not work correctly.

 

 

 

 

When power-up control wait is enabled (non-zero time), the controller remains off until one of two

Power-up control

conditions occurs:

wait

The controller exits power-up control wait once it receives communicated information.

 

The controller exits power-up control wait once the power-up control wait time expires.

 

 

Diagnostic present

A specific list of diagnostic affects valve operation. For more information see, Tracer™ ZN.520 Unit

Controller diagnostics, on page 52 for more information.)

 

 

 

 

The controller includes a manual output test sequence you can use to verify output operation and

Manual output test

associated output wiring. However, based on the current step in the test sequence, the valve(s) may not

 

be open. For more information see, Manual Output Test, on page 48 for more information.)

 

 

Fan mode off

When a local fan mode switch (provided on the Trane zone sensor) determines the fan operation, the

off position controls the unit off and valves to close.

 

 

 

 

You can communicate a desired operating mode (such as OFF, HEAT, and COOL) to the controller. When

Requested mode off

OFF is communicated to the controller, the unit controls the fan OFF. There is no heating or cooling

 

(valves are closed).

 

 

 

The controller includes entering water temperature sampling logic which is automatically invoked

 

during 2-pipe and 4-pipe changeover when the entering water temperature is either too cool or too hot

 

for the desired heating or cooling. For more information see, Entering Water Temperature Sampling,

Sampling logic

on page 43 for more information.)

Example: A 2-pipe heat/cool changeover unit will not cool if the entering water temperature is too

 

 

warm for cooling or if the entering water sensor is not present. The unit will not heat if the entering

 

water temperature is too cool for heating. If failed the controller will close valve for one hour then

 

reattempt sampling routine.

 

 

Table 31: Valves stay open

 

 

 

Probable cause

Possible Explanation

 

 

 

 

Unit wiring

The wiring between the controller outputs and the valve(s) must be present and correct for normal

valve operation.

 

 

 

Unit configuration

The controller must be properly configured based on the actual installed end devices and application.

When the unit configuration does not match the actual end devices, the valves may not work correctly.

 

 

 

Diagnostic present

A specific list of diagnostic affects valve operation. For more information see, Tracer™ ZN.520 Unit

Controller diagnostics, on page 52 for more information.)

 

 

 

 

The controller includes a manual output test sequence you can use to verify output operation and

Manual output test

associated output wiring. However, based on the current step in the test sequence, the valve(s) may be

 

open.For more information see, Manual Output Test, on page 48 for more information.)

 

 

 

The controller includes entering water temperature sampling logic which automatically invoked during

Sampling logic

2-pipe and 4-pipe changeover when the entering water temperature is either too cool or too hot for the

desired heating or cooling. For more information see, Entering Water Temperature Sampling, on page

 

 

43 for more information.)

 

 

UV-SVP01A-EN

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Image 62
Contents Installation Owner Diagnostics Tracer ZN.520 for Classroom Unit VentilatorStart-up Procedures Installation of New UnitsPower Up Sequence General Information Tracer ZN.520 OverviewGeneral Information Controller Circuit Board Features Tracer ZN.520 unit controller circuit boardTypical Components Controller FeaturesService Integrated Comfort System Communication ConfigurationsPeer-to-Peer Communications Interoperability Stand-AloneCommunication Interface Standard End Devices End Device SpecificationsCharacteristic DescriptionStandard End Devices Way Control Valve Time clock Zone sensor Dpdt Control Transformer Installation and Wiring SpecificationsBinary Inputs Binary Outputs Generic/baseboard Heat Binary OutputAnalog Inputs Analog inputsMounting Vertical classroom unit ventilator end pocket Wiring PowerInstalling the Wall- Mounted Zone Sensor Optional Proper zone sensor placementHumidity and CO2 Sensors Typical Wiring Diagram-Wall Mounted Zone Sensor Typical Wiring Diagram-Unit Mounted Zone Sensor Typical Wiring Diagram-Unit Input/Output Summary Input and output summaryInput/Output Summary Cooling source ConfigurationConfigurable parameters Heating sourceBinary Outputs1 Analog Inputs1 Binary input summary ConfigurationBinary Inputs1 Analog input summaryFan configuration ranges Fan ConfigurationEnd Device Configurations DefaultSetpoints Setpoint defaults Default Valid rangeDischarge air limit ranges Default Valid range Discharge Air LimitsMaintenance Timers Occupied Bypass TimerPower-Up Control Wait Winking Location IdentifierUnit Identification Tag Heating And Cooling Changeover Logic Power-UpUnit Operation OccupancyHeat/Cool Changeover logic Heating Operation Fan Off DelayCooling Operation Fan OperationExhaust fan/damper operation Valve OperationFace-and-Bypass Damper Operation Modulating ValvesUnit Configuration Entering Water Temperature SamplingWater assumption chart Temperature Assumed1Electric Heat Operation Economizer OperationDX Operation Baseboard Heat OperationFan Status Filter Status/ Maintenance TimerOutput Overrides Other ModesData Sharing-LonWorks Simple data sharing applicationMore 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 Black Service Push Button TroubleshootingRed Service LED Yellow Comm LEDTest Procedure Exit6Troubleshooting Discharge Air Temperature Limit Space Temperature FailureEntering Water Temperature Failure Outdoor Air Temperature FailureDiagnostics Troubleshooting Translating Multiple Diagnostics Rover service tool FansValves stay open Probable cause Possible Explanation ValvesValves stay closed Probable cause Possible Explanation Outdoor air damper stays closed Probable cause Explanation DX/Electric HeatOutside Air Damper Outdoor air damper stays open Probable Cause ExplanationTracer ZN.520 Unit Controller Replacement Replacing Circuit BoardsHardwired Thermistor Values Hardwired Setpoint AdjustmentFan Switch Resistance Values AppendixBinary configuration details Binary input or output Appendix-Binary ConfigurationBinary Configuration FunctionAppendix-Unit Operation Heat/cool mode input NviHeatCoolEffective heat/ cool mode output nvoHeatCool Unit Operation Based On The Effective HEAT/COOL OutputAppendix-Unit Operation Data Lists Configuration properties1Appendix-Data Lists Input/output listing1Set the Time and Day Setting the Time ClockAppendix-Timeclock Set the ProgramReview and Change Programs Override Program Manual OperationAppendix-Timeclock Appendix-Location Identifier Location Identifier Location Identifier Location Identifier Trane Company