509 06 2501 0205/20/2010

DNECOMZR020A02, DNECOMZR021A03 (For 3 to 12.5 Ton Units)and DNECOMZR062A00 (For RHS 12.5 Ton Heat Pump Units)

Vertical Economizer Accessory for Rooftop Units

Installation Instructions

TABLE OF CONTENTSSAFETY CONSIDERATIONS 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PACKAGE USAGE 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PACKAGE CONTENTS 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

INSTALLATION 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONFIGURATION 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

OPERATION 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHECKOUT FOR ECONOMIZER 11. . . . . . . . . . . . . . . . . . . . . . . .

SAFETY CONSIDERATIONSImproper installation, adjustment, alteration, service,maintenance, or use can cause explosion, fire, electrical shock, orother conditions which may cause death, personal injury, orproperty damage. Consult a qualified installer, service agency, oryour distributor or branch for information or assistance. Thequalified installer or agency must use factory--authorized kits oraccessories when modifying this product. Refer to the individualinstructions packaged with the kits or accessories when installing.Follow all safety codes. Wear safety glasses, protective clothing,and work gloves. Have a fire extinguisher available. Read theseinstructions thoroughly and follow all warnings or cautionsincluded in literature and attached to the unit. Consult localbuilding codes, the current editions of the National Fuel Gas Code(NFGC) NFPA 54/ANSI Z223.1, and the National Electrical Code(NEC) NFPA 70.In Canada refer to the current editions of the National Standardsof Canada CAN/CSA--B149.1 and .2 Natural Gas and PropaneInstallation Codes, and Canadian Electrical Code CSA C22.1.

Recognize safety information. This is the safety--alert symbol .When you see this symbol on the unit and in instructions ormanuals, be alert to the potential for personal injury. Understandthe signal words DANGER, WARNING, and CAUTION. Thesewords are used with the safety--alert symbol. DANGER identifiesthe most serious hazards which will result in severe personalinjury or death. WARNING signifies hazards which could result inpersonal injury or death. CAUTION is used to identify unsafepractices which may result in minor personal injury or product andproperty damage. NOTE is used to highlight suggestions whichwill result in enhanced installation, reliability, or operation.IMPORTANT: Do not adjust the economizer damper assembly.The actuator and damper have been pre--set and adjusted forproper operation.

ELECTRICAL OPERATION HAZARD

Failure to follow this warning could result in personal injury ordeath.Before performing service and maintenance operations onunit, turn off main power switch to unit.TAG DISCONNECT SWITCH WITH A SUITABLE LOCK ANDWARNING LABEL.

! WARNING

CUT HAZARD

Failure to follow this caution could result in personal injury.Sheet metal parts may have sharp edges or burrs. Use careand wear appropriate protective clothing, safety glasses, andgloves when handling parts and servicing roof top units.

! CAUTION

GENERALThe economizer system utilizes the latest technology available forintegrating the use of free cooling for packaged rooftop units. Thesolid-state control system optimizes energy consumption, zonecomfort, and equipment cycling by operating the compressorswhen the outdoor-air temperature is too warm, integrating thecompressor with outdoor air when free cooling is available, andlocking out the compressor when outdoor-air temperature is toocold. Demand ventilation is supported.The Economizer system utilizes gear-drive technology with adirect-mount spring return actuator that will close upon loss ofpower. The Economizer system comes standard with an outdoorair temperature sensor, supply air temperature sensor, and lowtemperature compressor lockout switch. Indoor enthalpy, andoutdoor enthalpy sensors are available for field installation.Barometric relief dampers provide natural building pressurizationcontrol. Barometric relief dampers are built into the design. Anoptional power exhaust system is available for applicationsrequiring even greater exhaust capabilities. The power exhaustset point is adjustable at the Economizer controller.See Table 1 for package usage. See Table 2 for packagecontents. See Table 3 for sensor usage.

TABLE 1 -- PACKAGE USAGEUNIT PART NUMBER

Small Cabinet-- Standard Efficiency 3--6 Ton,High Efficiency 3--5 Ton DNECOMZR020A02

Large Cabinet-- Standard Efficiency7.5--12.5 Ton, High Efficiency 6--8.5 Ton DNECOMZR021A003

Extra--Large Cabinet-- Standard Efficiency12.5 Ton RHS Heat Pumps DNECOMZR062A000

TABLE 2 -- PACKAGE CONTENTSPART NO. QTY CONTENTS

DNECOMZR020A02DNECOMZR021A03

1 Hood Top and Sides1 Hood Divider1 Aluminum Filter18 Screws1 Economizer Assembly1 Supply Air Temperature Sensor

DNECOMZR062A00

1 Hood Top and Sides1 Hood Divider1 Hood Filter Divider2 Aluminum Filter1 Hardware Bag1 Economizer Assembly1 Supply Air Temperature Sensor

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TABLE 3-- ECONOMIZER SENSOR USAGE

APPLICATION

ECONOMIZER WITH OUTDOOR AIRDRY BULB

Accessories Required

Outdoor AirDry Bulb

None. The outdoor air dry bulb sensoris factory installed.

SingleEnthalpy AXB078ENT

DifferentialEnthalpy

AXB078ENTand DNENTDIF004A00*

CO2 forDCV Control

using aDuct-MountedCO2 Sensor

DNCBDIOX005A00††

*DNENTDIF004A00 accessories are used on many different base units. As such,these kits may contain parts that will not be needed for installation.

††DNCBDIOX005A00 is an accessory that contains both 33ZCSENCO2 (CO2Sensor) and 33ZCASPCO2 (aspirator box) accessories.

TABLE 4 -- ACCESSORIES LISTTable 4 has several field--installed accessories available tooptimize performance. Refer to Table 4 for authorized parts.

DESCRIPTION PART NUMBER3--6 Ton Power Exhaust 208v--230v 1Ph DNPWREXH030A01

3--6 Ton Power Exhaust 460v 1Ph DNPWREXH021A01

7.5--12.5 Ton Power Exhaust 208v--230v1Ph DNPWREXH022A01

7.5--12.5 Ton Power Exhaust 460v 1Ph DNPWREXH023A01

Outdoor Air Enthalpy Sensor AXB078ENT

Indoor Air Enthalpy Sensor DNENTDIF004A00

Return Air CO2 Sensor (40 to 20 mA) DNCBDIOX002A00

INSTALLATIONSee Fig 1 for economizer component locations. To install theeconomizer, perform the following procedure:

1. Turn off unit power supply and install lockout tag.

ELECTRICAL OPERATION HAZARD

Failure to follow this warning could result in personal injury ordeath.

Before installing or servicing unit, always turn off all power tounit. There may be more than one disconnect switch.

! WARNING

2. Remove the existing unit filter access panel. Raise the paneland swing the bottom outward. The panel is now disengagedfrom the track and can be removed. See Fig. 2.

3. Remove the indoor coil access panel and discard. See Fig. 2

4. The box with the economizer hood components is shippedwith the economizer. Remove hood from packaging. Thehood top and sides are shipped factory assembled.

IMPORTANT: If the power exhaust accessory is to be installed onthe unit, the hood shipped with the unit will not be used and maybe discarded. Save the aluminum filter for use in the powerexhaust hood assembly.

5. Insert the hood divider between the hood sides. See Fig. 3.Secure hood divider with 2 screws (provided) on each hoodside. Screws should go through the hood sides into thedivider. The hood divider is also used as the bottom filter rackfor the aluminum filter.. On hood for extra large cabinet installfilter divider. See Fig. 4A.

6. Set the Economizer upright. (See Fig. 5.)

7. Slide the Economizer assembly into the rooftop unit. (See Fig.5). On small and large cabinets be sure to engage the rearEconomizer flange under the tabs in the return-air opening of

the unit base. (See Fig. 6)

8. Secure the Economizer to unit along side and bottom flangesusing the screws provided.

9. Remove the tape securing the relief dampers in place.

10. Remove and save the 12-pin jumper plug from the unit wiringharness (located in the upper left corner of the unit). Insert theEconomizer plug into the unit wiring harness. Refer to Fig. 7for wiring diagram.

NOTE: If the power exhaust accessory is to be installed onthe unit, the hood shipped with the Economizer will not be usedand may be discarded. Save the aluminum filter for use in thepower exhaust hood assembly.

11. The outside air temperature (OAT) is taped to the fronteconomizer divider plate for shipping purposes. Relocatesensor to operating position as shown in Fig. 1.

12. If Economizer will be operating under enthalpy control,replace the factory installed outdoor dry bulb temperaturesensor with accessory enthalpy sensor AXB078ENT. (SeeFig. 1.)

13. Remove the indoor fan motor access panel. (See Fig. 8.)14. The supply air temperature sensor looks like an eyelet

terminal with wires running to it. The sensor is located on the“crimp end” and is sealed from moisture. Mount the supply airtemperature sensor (provided) to the lower left section of theindoor fan blower housing. (See Fig. 9.) Use the screwprovided and use existing hole. Connect the violet and pinkwires to the corresponding connections on the supply airtemperature sensor. (See Fig. 7.)

NOTE: Be sure that the arrow on the actuator motor is pointing to“Run” and not to “Test.” If the arrow is at “Test,” the Economizerdamper will drive open. (Extra large cabinet only.)

FIGURE 1 Economizer Component Locations

FIGURE 2Typical Outdoor--Air Section Access PanelLocations

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FIGURE 3 Hood Assembly

Economizer A B C DShipWeight

DNECOMZR020A02 33.37 17.43 19.05 29.50 55

DNECOMZR021A03 40.37 22.28 24.48 36.27 80

DNECOMZR062A00 52.92 27.03 33.41 49.92 98

Measurement = Inches, Weight = lbs.

NOTE: The DNECOMZR062A00 hood has 2 aluminum filtersand a hood filter divider that installs between the filters. (See Fig.4A.)

FIGURE 4 Filter Installation

Hood for Extra Large CabinetFIGURE 4A

Hood FilterDivider

FIGURE 5 Economizer Installed in HVAC Unit

WIRINGHARNESS

ECONOMIZERCONTROLLER

ECONOMIZER

HVAC UNIT FILTERS

INSERTSCREWS INECONOMIZERFLANGES

FIGURE 6 Rear Economizer Flange Installation

UNIT FILTERRACK

UNIT BASE

ECONOMIZERHOLD DOWNTAB

ECONOMIZER REAR FLANGE

15. While everything is open install and wire any otheraccessories and/or sensors as applicable and convenient,per their installation instructions and/or the Configurationsection of this instruction. Some accessories require that unitducting already be installed.

NOTE:If also installing a power exhaust accessory, skip step 16and follow the power exhaust instructions instead.

16. Install the Economizer hood over the Economizer. Usescrews provided. (See Fig. 10.)

17. Review the controller setting options in the Configurationsection.a. The standard Economizer outdoor air sensor has a factory

setting of 63°F for the outdoor air temperature change overand 55° F for the supply air temperature sensor. The out-door air temperature changeover setting is adjusted on thesensor. See fig. 12. The ABCD potentiometer on the eco-nomizer controller should be set to the “D” position.

b. The low temperature compressor lockout switch setting isfixed at 42° F.

c. The minimum position for the outdoor damper can be con-figured at the controller. When not using CO2 sensors,set the DCV Max potentiometer to completely closed(CCW) to insure that the Minimum Position potentiometerfunctions correctly. When using a remote minimum positionpotentiometer, the Min Pos Pot on the controller must befully CW.

d. Settings on the optional outdoor enthalpy sensor, indoorenthalpy sensor, power exhaust and CO2 sensor can beconfigured at the controller.

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FIGURE 7 Economizer Wiring

Economizer Unit Without Economizer or2 Position Damper

FIGURE 8 Typical Indoor Fan Motor Access PanelLocations

FIGURE 9 Supply Air Sensor Placement

18. Check all wiring for safety then reapply power to the unit.Verify correct operation and setting of the accessory(s) per theConfiguration and Operations sections of the instruction.

19. Replace the indoor fan motor access panel.

20. Replace the filter access panel. Slide top of panel into trackand lift. Push bottom of panel into place.

21. Install the economizer hood filter(s) by opening the filter clipswhich are located underneath the hood top. Insert thealuminum filter(s) into the bottom filter rack (hood divider).Push the filter into position past the open filter clips. Close thefilter clips to lock the filter into place. (See Fig. 4.)

FIGURE 10 Economizer Hood Installation

ECONOMIZER

ECONOMIZERHOOD

MOUNTINGSCREWS

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CONFIGURATIONEconomizer Control Modes — Determine the Economizercontrol mode before set up of the control. Some modes ofoperation may require different sensors. Refer to Table 3. TheEconomizer is supplied from the factory with a supply airtemperature sensor, a low temperature compressor lockoutswitch, and an outdoor air temperature sensor. This allows foroperation of the Economizer with outdoor air dry bulb changeovercontrol. Additional accessories can be added to allow for differenttypes of changeover control and operation of the Economizer andunit.

TABLE 5 -- SUPPY AIR SENSOR TEMPERATURE /RESISTANCE VALUES

TEMPERATURE (F) RESISTANCE (ohms)

--58 211,250

--40 100,680

--22 53,010

--4 29,091

14 16,570

32 9,795

50 5,970

68 3,747

77 3,000

86 2,416

104 1,597

122 1,080

140 746

158 525

176 376

185 321

194 274

212 203

230 153

248 116

257 102

266 89

284 70

302 55

THERMOSTATS — The Economizer control works withconventional thermostats that have a Y1 (cool stage 1), Y2 (coolstage 2), W1 (heat stage 1), W2 (heat stage 2), and G (fan). TheEconomizer control does not support space temperature sensors.Connections are made at the thermostat section of the centralterminal board located in the main unit control box.NOTE: When using differential enthalpy control and “integratedeconomizer operation” is desired, a 2-stage cooling thermostat isrequired even on 1-stage cooling units (e.g. 2-6 ton rooftop units).A thermostat lead must be made between Y2-output onthermostat and Y2-input on rooftop unit�s Central Terminal Board(CTB). Internal wiring between Y2-input on the unit CTB and theeconomizer controller’s Y2 input already exists in unit wiringharness and the economizer plug, so no field modifications arerequired.OCCUPANCY CONTROL (R22 MODELS) — The factory defaultconfiguration for the Economizer control is occupied mode.Occupied status is provided by the black wire from Pin 3. Whenunoccupied mode is desired, install a field supplied timeclockfunction interrupting the black wire to the N terminal. (See Fig. 7)When the timeclock contacts are closed, the Economizer controlwill be in occupied mode. When the timeclock contacts are open(removing the 24-v signal from terminal N), the Economizer IV willbe in unoccupied mode.

OCCUPANCY CONTROL (R410A MODELS) — The factorydefault configuration for the Economizer control is occupied mode.Occupied status is provided by installing a field-supplied timeclockfunction on the OCCUPANCY terminals on the CTB (CentralTerminal Board) in the unit�s main control box and cutting the“CUT FOR OCCUPANCY” jumper on the CTB (See Fig. 17).When the timeclock contacts are closed, the Economizer controlwill be in occupied mode. When the timeclock contacts are openremoving the 24v signal from terminal N, the Economizer will be inunoccupied mode.

FIGURE 11 Economizer Controller Potentiometerand LED Locations

N1

N

P1

T1

AQ1

SO+

SR+

SR

SO

AQ

T

P

2V 10VSet

EXH

EXH

MinPos

Open

2V 10VMax

DCV

DCV

FREECOOL

DCV

Set10V2V

B

A D

C

Exhaust FanSetpoint

LED Lights WhenExhaust Contact

is madeMinimum Damper

Position SettingMaximum Damper Demand

Control VentilationSetpoint

LED Light when DemandControl Ventilation Input is

Above SetpointDemand Control

Ventilation Setpoint

LED Light when Outdoor Airis Suitable for Free Cooling

EnthalpyChangeover Setpoint

SUPPLY AIR TEMPERATURE (SAT) SENSOR — The supply airtemperature sensor is a 3 K thermistor located at the inlet of theindoor fan. (See Fig. 9) This sensor is field installed. Theoperating range of temperature measurement is 0� to 158� F.See Table 5 for sensor temperature/resistance values. Thetemperature sensor looks like an eyelet terminal with wiresrunning to it. The sensor is located in the “crimp end” and issealed from moisture.LOW TEMPERATURE COMPRESSOR LOCKOUT SWITCH —The Economizer is equipped with a low ambient temperaturelockout switch located in the outdoor airstream which is used tolock out the compressors below a 42° F ambient temperature.(See Fig. 1)OUTDOOR AIR TEMPERATURE (OAT) SENSOR — The outdoorair temperature sensor (HH57AC080) is a 10 to 20 mA deviceused to measure the outdoor-air temperature. The outdoor-airtemperature is used to determine when the Economizer can beused for free cooling. The sensor has 8 selectable temperaturechangeover set points, ranging from 48� F to 78� F. Thetemperature changeover is set using the 3 dip switches on thesensor. (See Fig. 12)OUTDOOR DRY BULB CHANGEOVER — The standardcontroller for field installed accessory economizers is shippedfrom the factory configured for outdoor dry bulb changeovercontrol. For this control mode, the outdoor temperature iscompared to a selectable set point on the OAT sensor. If theoutdoor air temperature is above the set point, the Economizer willadjust the outdoor air dampers to minimum position. If the outdoorair temperature is below the set point, the position of the outdoorair dampers will be controlled to provide free cooling usingoutdoor air. When in this mode, the Free Cool LED next to theoutdoor enthalpy set point (ABCD) potentiometer will be on. Thechangeover temperature set point is controlled by the dip switcheson the sensor. See Fig. 12 for the switch positions correspondingto the temperature changeover values. The ABCD potentiometeron the controller should be turned fully clockwise (CW) to the “D”position.

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FIGURE 12 Selectable Temperature Options

OUTDOOR ENTHALPY CHANGEOVER — For enthalpy control,accessory enthalpy sensor (part number HH57AC078) isrequired. Replace the standard outdoor dry bulb temperaturesensor with the accessory enthalpy sensor in the same mountinglocation. (See Fig. 1) When the outdoor air enthalpy rises abovethe outdoor enthalpy changeover set point, the outdoor-airdamper moves to its minimum position The outdoor enthalpychangeover set point is set with the outdoor enthalpy set point(ABCD) potentiometer on the Economizer controller. The setpoints are A, B, C, and D (See Figs. 11, 14 and 15). Thefactory-installed 620-ohm jumper must be in place acrossterminals SR and SR+ on Economizer controller. (See Fig. 7).When not using CO2 sensors, set the DCV Max potentiometer tocompletely closed (CCW) to insure that the Minimum Positionpotentiometer functions correctly.

DIFFERENTIAL ENTHALPY CONTROL -- For differential

enthalpy control, the economizer controller uses two enthalpysensors (AXB078ENT and DNENTDIF004A00), one in theoutside air and one in the return airstream. The economizercontroller compares the outdoor air enthalpy to the return airenthalpy to determine economizer use. The controller selects thelower enthalpy air (return or outdoor) for cooling. For example,when the outdoor air has a lower enthalpy than the return air andis below the set point, the economizer opens to bring in outdoorair for free cooling.

Replace the standard outside air dry bulb temperature sensor withthe accessory enthalpy sensor in the same mounting location.See Fig. 1. Mount the return air enthalpy sensor in the return airduct. See Fig. 7 and 13. When using this mode of changeovercontrol, turn the enthalpy set point potentiometer fully clockwise tothe D setting.POWER EXHAUST SET POINT ADJUSTMENT—If the optionalpower exhaust accessory is installed, the exhaust set point willdetermine when the power exhaust fan runs based on damperposition. The set point is modified with the Exhaust Fan Set Point(EXH SET) potentiometer. (See Fig. 15) The set point representsthe damper position above which the exhaust fans will be turnedon. When there is a call for exhaust, the Economizer controllerprovides a 45 +/-- 15 second delay before exhaust fan activationto allow the dampers to open. This delay allows the damper toreach the appropriate position to avoid unnecessary fan overload.

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution could result in equipmentdamage.If a separate field--supplied transformer is used to power theIAQ sensor, the sensor must not be grouded or theeoncomizer control board will be damaged.

! CAUTION

FIGURE 13 Return Air Sensor Mounting Location

ECONOMIZER

ECONOMIZERCONTROLLER

GROMMET

RETURN AIRSENSOR

RETURN DUCT(FIELD SUPPLIED)

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CONTROLCURVE

ABCD

CONTROL POINTAPPROX. deg. F (deg. C)

AT 50% RH

73 (23)70 (21)67 (19)63 (17)

12

14

16

18

20

22

24

26

28

30

32

34

36

38

40

42

44

46

90100

8070

6050

40

30

20

10

ENTH

ALPY

BTU

PER

PO

UND

DRY

AIR

85(29)

90(32)

95(35)

100(38)

105(41)

110(43)

35(2)

35(2)

40(4)

40(4)

105(41)

110(43)

45(7)

45(7)

50(10)

50(10)

55(13)

55(13)

60(16)

60(16)

65(18)

65(18)

70(21)

70(21)

75(24)

75(24)

80(27)

80(27)

85(29)

90(32)

95(35)

100(38)

A

A

B

B

C

C

D

DR

ELA

TIV

E H

UM

IDIT

Y (%

)

HIGH LIMITCURVE

APPROXIMATE DRY BULB TEMPERATURE--degrees F (degrees C)

FIGURE 14 Enthalpy Changeover Set Points

FIGURE 15 Economizer Controller FIGURE 16 Proportional and Exponential Control

Design Ventilation Rate

Exponential ControlApproachProportional CO2 ControlApproach

Minimum Position = VsMaximum Position = Vs + Vp

Relay ControlApproach

BaseVentilation For Sources

1000CO2 Differential

Equi

libriu

mC

O2

Con

cent

ratio

nFo

rTar

getV

entil

atio

nR

ate

(15

CFM

=∆

700

PPM

)

Incr

easi

ngVe

ntila

tion

Ve

CO2 DCV

DeadbandSettingSetpoint

8 509 06 2501 02

MINIMUM DAMPER POSITION CONTROL —There is a minimumdamper position potentiometer on the Economizer controller. (SeeFig. 11). Adjust the Min Pos potentiometer to allow the minimum orbase amount of outdoor air, as required by local codes, to enterthe building. Make minimum position adjustments with at least10°F temperature difference between the outdoor and return-airtemperatures. The minimum damper position maintains theminimum airflow for full occupancy into the building during theoccupied period when demand control ventilation is not beingused).When the control is operating in Demand Control Ventilation(DCV) mode (see separate section following), the minimumdamper position sets the minimum ventilation position for VOC(volatile organic compound) contaminant removal during lightlyoccupied periods. In this mode the DCV Max potentiometer isused for fully occupied ventilation.NOTE: When DCV is not being used, set the DCV Maxpotentiometer to completely closed (CCW) to insure that theMinimum Position potentiometer functions correctly. If the DCVMax is set more open than Min Pos and

9509 06 2501 02

following. Background CO2 level is around 400 ppm and atypical starting ventilation threshold is 600 ppm abovebackground for a total value of 1000 ppm. The factory defaultsetting on factory-supplied sensors is a measuring range of 0-2000 ppm with a 0-10 Vdc proportional (linear) output. Thismeans 1000 ppm would result in ~5V output. The DCV Setpotentiometer comes from the factory set at 50%, but it is 50%of 2-10Vdc which is 6 Vdc, not 5. To set the DCV Setpotentiometer correctly to activate DCV at 1000ppm of CO2you must do one of the following:

S Provide a 5 Vdc signal (3 fresh batteries in series would giveyou ≥4.5 Vdc, probably closer to 4.8 Vdc) and adjust thepotentiometer until the DCV LED just lights, or

S Estimate setting by adjusting pot 3/8 turn clockwise for 5 Vdcsetting.

S Don’t touch the pot at all. Instead adjust the voltage outputrange on the CO2 sensor from 0-10 Vdc default to 2-10Vdc so it matches the pot. See also the CO2 SENSORCONFIGURATION section following.

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution could result in equipmentdamage.If a separate field--supplied transformer is used to power theIAQ sensor, the sensor must not be grounded or theeconomizer control board will be damaged.

! CAUTION

CO2 / INDOOR AIR QUALITY (IAQ) SENSOR - Mount theaccessory IAQ sensor according to manufacturer specifications inthe space or return air duct. The IAQ sensor should be wired tothe AQ and AQ1 terminals of the controller.CO2 SENSOR CONFIGURATION -- Set up the CO2 sensoraccording to the manufacturer�s instructions that come with theunit. The default setting on factory-supplied sensors is ameasuring range of 0 - 2000 ppm CO2 concentration with a 0 - 10Vdc proportional (linear) output. If you followed the instructionsabove these settings should be fine as is.NOTE: The Economizer control assumes the presence of acorrectly functioning CO2 sensor if the voltage across the AQ –AQ1 terminals ≥ 1 Vdc, because it assumes the sensors are setup for 2 – 10 Vdc output. Otherwise it will not operate in DCVmode and instead opens the dampers to the more open of theMIN POS and DCV Max set points. factory-supplied sensors�default settings are 0 – 10 Vdc, but because there is always CO2in the air, you should still read at least 2 Vdc under normalcircumstances. However if you reprogram the factory-suppliedsensors (to increase the range, change the output voltage, etc.) itis possible to lower the sensor voltage output to where you mighthave problems. Therefore, if you reprogram a factory-suppliedCO2 sensor, you should also adjust the minimum voltage outputup from 0 to 2 Vdc to avoid this issue.Factory-supplied sensors offer the option of changing to anexponential anticipatory response (see Fig. 16) which generateshigher output voltages at midrange sensor readings to make thecontroller introduce more outside ventilation air at lower CO2concentrations. Continuing the example from step 3 of theDEMAND CONTROLLED VENTILATION section, if after DCV Setadjustment you changed the CO2 sensor from proportional toexponential, the sensor voltage output would reach 5 Vdc at aCO2 concentration below 1000 ppm, fooling the controller intoopening sooner to anticipate ventilation demands. Exponentialanticipatory response would be appropriate for zones with:

Slarge air volumes such as gyms or theaters where higherCO2 levels might take a while to build up or reach thesensor.

S widely varying occupancy levels

SHVAC equipment that cannot exceed the required ventilationrate at design conditions. Exceeding the requiredventilation rate means the equipment can condition air at amaximum ventilation rate that is greater than the requiredventilation rate for maximum occupancy.

NOTE: The exponential anticipatory response setting only actuallyworks like it should if the Economizer control DCV Setpotentiometer is adjusted based on the original linear output. Ifyou adjust it using the actual value of exponential voltage outputfrom the sensor, it will not respond any faster.DEHUMIDIFICATION OF FRESH AIR WITH DCV CONTROL—Information from ASHRAE indicates that the largest humidityload on any zone is the fresh air introduced. For someapplications, an energy recovery unit can be added to reduce themoisture content of the fresh air being brought into the buildingwhen the enthalpy is high. In most cases, the normal heating andcooling processes are more than adequate to remove thehumidity loads for most commercial applications. If normal rooftopheating and cooling operation is not adequate for the outdoorhumidity level, an energy recovery unit and/or a dehumidificationoption should be considered.

OPERATIONWhen outside air temperatures are below return air temperaturesthe possibility exists for “free cooling,” similar to opening a windowinstead of turning on your air conditioner. The EconoMi$er opensoutdoor air dampers to admit cool outside air to the inlet of thesupply air fan instead of activating the unit�s compressor(s). Thisopening is controlled by a variety of standard and optional controlstrategies based on temperature, enthalpy and/or CO2 content ofindoor and/or outdoor air. Relief dampers dump relatively hotterreturn air outdoors at the same time, optionally assisted by thepower exhaust accessory. See Table 6 for a summary of controllerlogic.SEQUENCE OF OPERATION—For Economizer operation, theremust be a thermostat call for the fan (G). This will move thedamper to its minimum position (as controlled by the MIN POSpotentiometer) during the occupied mode. When outside airconditions are such that free cooling is not available, thecompressor will be controlled by the thermostat. If free cooling canbe used, as determined from the appropriate sensors (dry bulbtemperature, enthalpy, or differential enthalpy) and changeovercontrol schedule, a call for cooling (Y1 closes at the thermostat)will cause the Economizer control to provide a 50° to 55°Fsupply-air into the zone. As the supply air temperature (SAT)fluctuates above 55°F concurrent with Compressor 1 operation,the low ambient lockout thermostat will block compressoroperation with Economizer operation below 42°oF outside-airtemperature.If a field-installed accessory CO2 sensor is connected to theEconomizer control, a demand controlled ventilation strategy willbegin to operate in parallel with the free cooling strategy. As theCO2 level in the zone increases above the CO2 set point position(as controlled by the DCV set potentiometer), the position of thedamper will be increased proportionally to the DCV Max position(as controlled by the DCV Max potentiometer). As the CO2 leveldecreases because of the increase in fresh air, the outdoor-airdamper will be proportionally closed back down to the minimumopen position. Damper position will follow the higher demandcondition from the DCV mode or free cooling mode.Performance Data — Refer to Fig. 18 for barometric reliefcapacity. Refer to Fig. 19 for return air pressure drop.

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FIGURE 18 Barometric Relief Flow Capacity

0

500

1000

1500

2000

2500

0 0.05 0.1 0.15 0.2 0.25 0.3

RELIEFFLOW

(CFM)

R ETURN DUCT STAT IC PRESSURE ( i n . w g )

SmallCabinet

Large andExtra LargeCabinet

FIGURE 19 Return Air Pressure Drop

0

1000

2000

3000

4000

5000

6000

0 0. 1 0. 2 0. 3 0. 4

RETURNAIR

FLOW

(CFM)

R ETURN DUCT STAT IC PRESSURE DROP ( i n . w g )

Small CabinetLarge Cabin-etExtra LargeCabinet

TABLE 6 -- ECONOMIZER INPUT / OUTPUT LOGICINPUTS OUTPUTS

Demand Control

Ventilation (DCV)

Enthalpy A

Y1 Y2

Compressor N Terminal B

Outdoor Return

Stage

1

Stage

2Occupied Unoccupied

Damper

Below set(DCV LED Off)

High(Free Cooling LED Off) Low

On On On OnMinimum position ClosedOn Off On Off

Off Off Off Off

Low(Free Cooling LED On) High

On On On Off ModulatingC (between min.position and full-open)

ModulatingC (betweenclosed and full-open)On Off Off Off

Off Off Off Off Minimum position Closed

Above set(DCV LED On)

High(Free Cooling LED Off) Low

On On On OnModulatingD (between min.position and DCV maximum)

ModulatingDG (betweenclosed and DCVmaximum)

On Off On OffOff Off Off Off

Low(Free Cooling LED On) High

On On On OffModulatingE ModulatingFOn Off Off Off

Off Off Off OffA For single enthalpy control, the module compares outdoor enthalpy to the ABCD set point.B Power at N terminal determines Occupied/Unoccupied setting: 24 vac (Occupied), no power (Unoccupied).C Modulation is based on the supply-air sensor signal.D Modulation is based on the DCV signal. If the CO2 sensor input (AQ-AQ1) terminals is < 1Vdc or the sensor has failed, the motor will drive to MIN POS or DCV MAX

which ever is highest.E Modulation is based on the greater of DCV and mixed air sensor signals, between minimum position and either maximum position (DCV) or fully open (mixed air sig-

nal).F Modulation is based on the greater of DCV and mixed air sensor signals, between closed and either maximum position (DCV) or fully open (mixed air signal).G Modulation is based on the DCV signal, if the CO2 sensor input (AQ-AQ1) terminals is < 1Vdc or the sensor has failed, the motor will drive DCV MAX in occupied

mode. When power is cut to the economizer (fan is off) then the damper will spring return closed.

CHECKOUT AND TROUBLESHOOTINGCheckout requires a 9V battery, 620 ohm, 1.2K ohm, 5.6K ohm,and 6.8K ohm resistors. Use table 7 and Fig. 20 for checkout.

EQUIPMENT DAMAGE HAZARD

Excessive force can damage potentiometer controls.Use a small screwdriver when adjusting enthalpy changeoverand minimum damper position controls.

! CAUTIONFIGURE 20

Meter Location for Checkout andTroubleshooting

N1

P1

T1

N 2V

2V

2V

B

A

SR

SO

AQ

C

D

FreeCool

10V

EXH

DCV

EXHSet

10V

DCV

Max

10V

DCV

Set

MinPos

Open

P

T

AQ1

SO+

SR+

1

2

DC VOLTMETER

620 OHM RESISTOR

W7212

+

S

+C7400

1

2

INSERT DC VOLTMETER BETWEEN AQ AND AQ1 FORCHECKOUT AND TROUBLESHOOTING.

JUMPER USED FOR SINGLE ENTHALPY CONTROL.

11509 06 2501 02

TABLE 7 -- CHECKOUT FOR ECONOMIZER

Step Checkout Procedure Proper Response1. CHECKOUT PREPARATION FOR ECONOMIZING ONLY

Disconnect power at TR and TR1. All LED are off; Exhaust Fan contacts are openDisconnect devices at P and P1Jumper P to P1 (defaults to on board MIN POS potentiometer)Place 5.6K ohm resistor across T and Ta1 (Blue sleeve provides input toeconomizer that the MAT is between 50-55°F.Jumper TR to 1 (call for cooling from the thermostat).W7212 only: Jumper TR to N (places economizer in occupied mode).If connected, remove C7400 Enthalpy Sensor from terminals SO and +.Connect 1.2K ohm, from 4074EJM Checkout Resistor kit, (purple sleeve)across terminals SO and + (makes OA enthalpy high).Place 620 ohm resistor (white sleeve) across SR and + (makes returnenthalpy lower than OA).Set MIN POS and DCV MAX potentiometers fully CCW.Turn DCV setpoint potentiometer mid position (this sets the DCV ventilationat approximately 1000 ppm).Turn exhaust potentiometer to mid position (motor will be approximately 50%open when the exhaust fan contacts make).Set enthalpy potentiometer to D.Apply power (24 Vac) to terminals TR and TR1.

2. DIFFERENTIAL ENTHALPYExecute step one, Checkout Preparation ---Turn DCV MAX to mid position.Place 620 ohm resistor across SO and + (white sleeve resistor makes OAenthalpy low).

---

Place 1.2K ohm resistor across SR and + (purple sleeve resistor makes RAenthalpy high).

Free cool LED turns on; motor drives to approximately 45 degrees (half)open.

Remove 620 ohm resistor from SO and + . Free cool LED turns off; motor drives closed.3. SINGLE ENTHALPY

Execute step one, Checkout Preparation ---Turn DCV MAX to mid position.Set enthalpy potentiometer to A (fully CCW). Free cool LED turns on; motor drives to approximately 45 degrees (half)

open.Set enthalpy potentiometer to D (fully CW). Free cool LED turns off; motor drives closed.

4. DCV AND EXHAUSTExecute step one, Checkout Preparation ---LED for both DCV and Exhaust should be off.Turn DCV MAX to mid position. Motor drives to mid position, 45 degrees open.Turn MIN POS fully CW. Motor drives to fully open.Turn MIN POS and DCV MAX to fully CCW. Motor drives closedTurn DCV MAX to mid position. Connect 9v battery positive to AQ andnegative to AQ1.

LED for both DCV and Exhaust turn on.Actuator drives to 45 degrees open.

Remove jumper from N terminal (economizer goes into not occupied mode). Motor remains at 45 degrees open.Adjust DCV MAX towards CW. Motor will move to position set by DCV MAX pot.Adjust DCV MAX towards CCW. Motor will drive closed.Reconnect jumper to N terminal.Adjust DCV MAX and MIN POS pots. Motor will drive to the most open position of the pots.Adjust DCV MAX and MIN POS pots to fully CCW.Remove power from N terminal adjust MIN POS towards CW. Motor should not move.Adjust DCV MAX towards CW. Motor will move to position set by DCV MAX pot.

12 509 06 2501 02

TABLE 7 -- CHECKOUT FOR ECONOMIZER (CONT.)

5. MINIMUM AND MAXIMUM POSITIONExecute step one, Checkout Preparation ---Connect 9V battery positive to AQ and negative to AQ1. Adjust DCV MAXpotentiometer to mid position.

DCV LED turns on. Actuator drives to 45 degrees open.

Turn DCV maximum position potentiometer to fully CCW. Actuator drives fully closed.Turn minimum position potentiometer to midpoint. Actuator drives to 45 degrees open.Turn minimum position potentiometer fully cw. Actuator drives fully open.Turn MIN POS in full CCW. Actuator drives fully closed.W7212: Remove jumper from TR and N. Actuator drives fully closed.

6. MIXED AIR INPUTExecute step one, Checkout Preparation ---Turn DCV MAX to mid position, set enthalpy potentiometer to A. Free cool LED turns on.

Actuator drives to 45 degrees open.Remove 5.6K ohm resistor (green sleeve) and place jumper from T and T1. Actuator drives to 45 degrees open.Remove jumper from T and T1 and leave open. Actuator drives fully closed.