Modulating outdoor air damper position | Trane Zone Controller

Chapter 5 Sequence of operations

low-speed fan operation. A controller can also receive a BAS-communi- cated outdoor air damper minimum position.

A BAS-communicated minimum position setpoint has priority over all locally configured setpoints. When a communicated minimum position setpoint is not present, the controller uses the configured minimum posi- tion for low fan speed whenever the fan is running at low speed, regard- less of the occupancy state. See Table 9 and Table 10 for more information about how the controller determines the position of the modulating out- door air damper.

Table 9. Modulating outdoor air damper position setpoint determination

	Occupancy	BAS-communicated	Fan speed	Active minimum setpoint
	Occupancy	setpoint	Fan speed	Active minimum setpoint
		setpoint

	Unoccupied	Any value	Any value	0% (closed)

	Occupied	Valid	Any value	BAS-communicated
	Occupied bypass
	Occupied standby

	Occupied	Invalid	Low	Occupied low fan minimum
	Occupied bypass
	Occupied standby

	Occupied	Invalid	Medium/high	Occupied minimum
	Occupied bypass

	Occupied standby	Invalid	Medium/high	Occupied standby minimum

Table 10. Relationship between outdoor temperature sensors and damper position

	Modulating outdoor air damper position
Outdoor air temperature	Occupied or occupied		Occupied standby		Unoccupied
Outdoor air temperature

	bypass
	bypass

No or invalid outdoor air	Open to occupied		Open to occupied standby		Closed
temperature	minimum position		minimum position

Failed outdoor air sensor	Open to occupied		Open to occupied standby		Closed
	minimum position		minimum position

Outdoor air temperature	Economizing; damper		Economizing; damper		Open and economizing
present and economizing	controlled between		controlled between		during unit operation; oth-
possible1	occupied minimum		occupied standby		erwise closed
	position and 100%		minimum position and
			100%

Outdoor air temperature	Open to occupied mini-		Open to occupied standby		Closed
present and economizing	mum position		minimum position
not possible1

1For an explanation of the economizing feature, see “Economizing (free cooling)” on page 45.

44	CNT-SVX07C-EN

Image 54

Trane Zone Controller, N512, CNT-SVX07C-EN manual Modulating outdoor air damper position

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 description Dimensions Storage environmentClearances Plastic-cover model dimensions and clearances Agency listing/compliance Additional components Zone humidity sensor Tracer zone temperature sensor optionsDamper actuators CO2 sensor Overview and specifications Input/output terminal wiring AC-power wiring General wiring information Communication-link wiring and addressing General wiring information Location recommendations Operating environment requirements Mounting recommendations Mounting the Tracer ZN521 zone controller ControlValve Economizing Typical applications for the Tracer ZN521 zone controllerApplication SpeedfanMultiple Dehumidification HeatElectric BI2 Condensate overflow BI1 Low-coil-temperature detectionBinary inputs Binary inputs BI3 Occupancy or generic binary input BI4 Fan status GND Ground terminals ZN Zone temperatureAnalog inputs Analog inputs FAN Fan mode input AI1 Entering water temperatureSET Local setpoint AI2 Discharge air temperature AI3 Outdoor air temperature or generic temperature AI4 configuration options and associated measurement ranges Configuration Measurement rangeAI4 Universal 4-20 mA AI4 terminal wiring CO2 measurement Binary output functions Binary outputsGeneric binary output Binary output Functions Required controller inputs for proper operation Wiring requirements and optionsOverriding binary outputs Function Input source For more information See Two-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 start Occupied standby mode Occupied modeUnoccupied mode Occupancy modes Occupied bypass mode Timed override control Zone temperature control Cascade zone controlSimplified zone control Morning warm-up Heating or cooling modeDischarge air tempering Morning cool-down Entering water temperature sampling function Fan operation Exhaust control Exhaust control Modulating valve calibration Valve operationModulating valve operation Valve control options Isolation-valve operation Modulating outdoor/return air dampersTwo-position valve operation Two-pipe operation Modulating outdoor air damper position Ashrae Cycle 1 conformance Ashrae Cycle 2 conformanceEconomizing free cooling DX cooling operation Two-position control of a modulating outdoor air damperFace-and-bypass damper operation Face-and-bypass, isolation-valve operation Electric heat operation Baseboard heat operationDehumidification Peer-to-peer communication Unit protection strategies Fan off delay Smart resetLow-coil-temperature protection Condensate overflow Filter-maintenance timer Freeze protection discharge air temperature low limitFreeze avoidance Test button Tracer ZN521 zone controller circuit board Manual output test For non Output Close damper, air Outdoor Open damper, air Outdoor Step Result BOP1 BOP2 BOP3 BOP4 BOP5 BOP6 BOP7 BOP8 BOP9 Interpreting LEDs Service pin buttonRed LED Service indicator LED activity Explanation Green LED Status indicator Yellow LED Communications indicator Diagnostics Types of diagnostics Diagnostic Probable cause Consequences Type Table of diagnosticsDiagnostics Fan unaffected Valved unaffected Position Damper unaffected Status indicators for operation and communication Fan does not energize Probable cause Explanation Troubleshooting Valves remain closed Valves remain open DX or electric heat does not energize Outdoor air damper remains closed Outdoor air damper remains open Outdoor air damper remains open Troubleshooting Index Numerics Index Index Index Page Trane