63-2684—01 - W7459A,B,C,D Solid State …B,C,D SOLID STATE ECONOMIZER™ LOGIC MODULE 63-2684—01...

PRODUCT DATA

63-2684-01

W7459A,B,C,D Solid State Economizer™ Logic Module

APPLICATION

The W7459 Solid State Economizer™ Logic Module is used with C7400 Solid State Enthalpy Sensors or C7660 Solid State Dry Bulb Temperature Sensors and M7405, M7415 or M8405 Damper Actuators to proportion outdoor and return air dampers for economizer control in commercial HVAC equipment.

FEATURES

• Operates from cooling space thermostat to provide a totally integrated control system.

• Solid state control package provides improved accuracy, reliability and stability.

• Combines solid state enthalpy or dry bulb changeover control, minimum damper position potentiometer (W7459A,B,D) and compressor staging relay functions.

• Optional differential enthalpy control provides greater economizer savings than single enthalpy control by selecting the most economical air for cooling (return or outdoor air).

• Housed in high-impact, glass-fiber reinforced plastic case to match lines of M7405, M7415, and M8405 Damper Actuators.

• Enthalpy setpoint on W7459 Economizer sets combination of air temperature and humidity suitable for free cooling.

• W7459A, B and D models include a built-in adjustable potentiometer to set minimum position and minimum amount of outdoor air admitted to meet minimum ventilation requirements. Terminals included for connecting an optional remote minimum position potentiometer for remote damper control.

• LED on W7459 indicates free cooling is available.

• W7459A mounts on M7415 Proportioning Actuator. It accepts input from discharge air temperature sensors, mixed air temperature sensors, enthalpy (or dry bulb temperature) sensors, and an optional remote minimum position potentiometer.

• W7459B mounts on M7405 Proportioning Actuator. It accepts direct digital control signals from W7401/W7411 Logic Panel, C7400 Solid State Enthalpy Sensors, or C7660 Solid State Dry Bulb Temperature Sensors and an optional remote minimum position potentiometer.

• W7459C mounts on M8405A Three-Position Actuator. It accepts input from a single-pole, single-throw (spst) mixed or discharge air control and C7400 Solid State Enthalpy Sensors or C7660 Solid State Dry Bulb Temperature Sensors.

• W7459D mounts on M7415 Proportioning Actuator. It accepts input from discharge air temperature sensors, mixed air temperature sensors, or enthalpy sensors and optional remote minimum damper position potentiometers. W7459D returns to mechanical cooling when outdoor air enthalpy reaches preset limits.

ContentsApplication ........................................................................ 1Features ........................................................................... 1Specifications ................................................................... 2Ordering Information ........................................................ 2Installation ........................................................................ 3Settings and Adjustments ................................................. 12Operation .......................................................................... 13Checkout and Troubleshooting ......................................... 14

W7459A,B,C,D SOLID STATE ECONOMIZER™ LOGIC MODULE

63-2684—01 2

ORDERING INFORMATION

When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the TRADELINE® Catalog or price sheets for complete ordering number.

If you have additional questions, need further information, or would like to comment on our products or services, please write or phone:

1. Your local Honeywell Automation and Control Products Sales Office (check white pages of your phone directory).2. Honeywell Customer Care

1885 Douglas Drive NorthMinneapolis, Minnesota 55422-4386

In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Toronto, Ontario M1V 4Z9.International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.

SPECIFICATIONS

Models: See Table 1.

Electrical Ratings (W7459/C7400):Input Voltage: 24 Vac, 50/60 Hz.Power Consumption: 5.5 VA.Relay Contact Ratings at 24 Vac:

Run: 1.5A.Inrush: 3.5A.

Temperature Ratings:Operating Ambient: -25°F to 125°F (-32°C to +52°C).Humidity: 5% to 95% RH.

Approvals:Underwriters Laboratories Inc. Flammability Rating UL94V-5V.

W7459D Maximum Outdoor Enthalpy Switching: See Table 2.

Enthalpy Input Connection (C7400):2-wire (18, 20, 22 AWG) connection.Can be mounted up to 200 ft away.

Dry Bulb Temperature Input (C7660):2-wire (18, 20, 22 AWG) connection.Can be mounted up to 200 ft away.

Dimensions: See Fig. 1.

Minimum Position Potentiometer:Resistance: 250 ohms.Setting: 0 to 100% of motor stroke.

Accessories:4074EJM 620 ohm Resistor, Jumper, and 1.2K ohmCheckout Resistor.4074EJQ Board for panel mounting W7459A,D.C7046A Discharge Air Temperature Sensor.C7150B Mixed Air Temperature Sensor.C7400 Solid State Enthalpy Sensor.C7660 Solid State Dry Bulb Temperature Sensor.T675, T6031 or T775 Remote Bulb Control for low ambient

lockout.S963B1128 Remote Minimum Position Potentiometer to pro-

vide remote control of damper position.ST6008 Energy Management Timer for occupied/unoccupied

control.

a W7459D has a high enthalpy limit and defaults to mechanical cooing when the outdoor enthalpy reaches the preset limit. Do not use a dry bulb sensor for a high temperature limit.

Table 1. W7459 Economizer Models.

ModelFor Use with

ActuatorDischarge Air

Temperature InputMinimum Position

Potentiometer AdjustmentTerminals for Remote

Minimum Damper PositionOutput Relays

W7459A M7415 C7150B or C7046A Sensor

Yes Yes 2 spdt

W7459B M7405A Direct digital control W7401/W7411 Logic Panel

Yes Yes 1 spdt

W7459C M8405 Spst control No. Minimum position adjustment is built into M8405 Actuator.

No 2 spdt

W7459Da M7415 C7150B or C7046A Sensor

Yes Yes 2 spdt


3 63-2684—01

INSTALLATION

When Installing this Product...1. Read these instructions carefully. Failure to follow them

could damage product or cause a hazardous condition.2. Check ratings given in instructions and on product to

make sure product is suitable for your application.3. Installer must be a trained, experienced service techni-

cian.4. After installation is complete, check out product opera-

tion as provided in these instructions.

Fig. 1. W7459 dimensions in in. (mm).

CAUTIONElectrical Shock or Equipment Damage Hazard.Can shock individuals or short equipment circuitry.Disconnect power supply before installation.

Location And Mounting

W7459 Economizer Control PackageThe W7459 Economizer mounts on the side of M7405, M7415, or M8405 Damper Actuator. When planning installation, allow enough clearance for maintenance and service. Install the W7459 Economizer Control Package where it is protected from rain and snow. Mount the actuator; then secure the W7459 to the actuator with one mounting screw (supplied). See Fig. 2.

Fig. 2. Mounting W7459 on Damper Actuator.

C7400 Solid State Enthalpy Sensor

OUTDOOR AIR SENSING1. Mount the C7400 Solid State Enthalpy Sensor where it is

exposed to freely circulating air and protected from rain, snow, and direct sunlight. Mount using any orientation.

2. Connect sensor to the SO and + terminals of the W7459A,B,C or D.

Table 2. W7459D Free Cooling Mode Switching.

Outdoor RH (percent) ON (LED on) with Decreasing Outdoor Enthalpy OFF (LED off) with Increasing Outdoor Enthalpy

25 83°F ±0.5°F (28°C ±0.3°C) 85°F ±0.5°F (29°C ±0.3°C)

50 78°F ±0.5°F (26°C ±0.3°C) 80°F ±0.5°F (27°C ±0.3°C)

60 76°F ±0.5°F (24°C ±0.3°C) 78°F ±0.5°F (26°C ±0.3°C)

75 73°F ±0.5°F (23°C ±0.3°C) 75°F ±0.5°F (24°C ±0.3°C)

M9085A

2-3/16(56)

4-1/16(103)

7/8 (22)

5/8(16)

2-13/16 (71)

1-1/4(32)

M9091W7459 ECONOMIZER PACKAGE

M7415, M7405 OR M8405 ACTUATOR


63-2684—01 4

RETURN AIR SENSING1. For differential enthalpy control, mount a second C7400

Solid State Enthalpy Sensor in the return air duct.2. Connect sensor to the SR and + terminals of the

W7459A,B,C or D.

C7660 Solid State Dry Bulb Temperature Sensor

IMPORTANTDo not use a C7660 with the W7459D or in a differen-tial dry bulb application. Differential applications should only use enthalpy sensors.

OUTDOOR AIR SENSING1. Mount the C7660 Solid State Dry Bulb Sensor where it is

exposed to freely circulating air and protected from rain, snow, and direct sunlight.

NOTE: Mount in any orientation to scoop the maximum amount of air into the device. Make sure the air flow-ing into the inlet ports is linear.

2. Connect sensor to the SO and + terminals of the W7459A,B, or C.

RETURN AIR SENSING1. For differential control, use enthalpy only and mount a

C7400 enthalpy sensor in the outdoor and return air duct.

2. Connect sensor to the SR and + terminals of the W7459A,B, or C.

NOTE: See Fig. 3 for typical organization of a W7459 Econo-mizer System.

WIRING

CAUTIONElectrical Shock or Equipment Damage Hazard.Can shock individuals or short equipment circuitry.Disconnect power supply before installation.

Refer to Fig. 4 through 10 for typical wiring diagrams:

Fig. 3. Location of C7400 Outdoor and Return Air Sensors, C7150 Mixed Air Sensor, and C7046 Discharge Air Sensor in a W7459 Economizer System.

DISCHARGEAIR SENSOR

C7046ADIRECT EXPANSIONCOIL

M7415 ACTUATORWITH W7459AECONOMIZERCONTROL PACKAGE

C7400

ENTHALPYSENSOR

C7400 ENTHALPYSENSOR

RETURN AIR

OUTDOORAIR

C7150B

MIXED AIRSENSOR

SPACE THERMOSTATOR T7400/W7400PROGRAMMABLESINGLE ZONESYSTEM

FOR DIFFERENTIAL ENTHALPY, TWO C7400 ENTHALPY SENSORS ARE CONNECTED TO W7459 ECONOMIZER CONTROL. ONE IS MOUNTED IN RETURN AIR; THE OTHER IS MOUNTED IN OUTDOOR AIR. DIFFERENTIAL ENTHALPY CONTROL PROVIDES GREATERENERGY SAVINGS THAN SINGLE ENTHALPY.

M10119

1

1

1


5 63-2684—01

Fig. 4. W7459A/C7400 or W7459D/C7400 used in one-stage cooling system with single enthalpy changeover, M7415 Actuator, and one-stage cooling thermostat.

L1 (HOT)

L2

FDR

FDR

FAN

FANDELAYRELAY

HEAT 1

HEAT 2

COOL 1

HVAC EQUIPMENTTERMINAL STRIP

POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.

MOTOR SPRING-RETURNS CLOSED WHEN FAN IS NOT RUNNING.

ENSURE THAT EQUIPMENT TRANSFORMER IS SIZED TO HANDLE THE EXTRA LOAD OF THE ECONOMIZER AND ACTUATOR.

1S IS AN ELECTRONIC SWITCH THAT CLOSES WHEN POWERED BY A 24 VAC INPUT.

RELAYS 1K AND 2K ACTUATE WHEN THE ENTHALPY SENSED BY THE C7400 IS HIGHER THAN THE ENTHALPY SETPOINT A-D.

FACTORY INSTALLED 620 OHM, 1 WATT, 5% RESISTOR SHOULD NOT BE REMOVED. DIFFERENTIAL ENTHALPY NOT RECOMMENDED FOR USE WITH SINGLE STAGE COOLING THERMOSTAT.

FOR T7300 ONLY.

WITH T7300, USE CONTACTS A1 AND A2 INSTEAD OF A TIMER.M10114A

T7300 OR T874THERMOSTAT

T1

P1P1P

T1

1

3 4

2

5

2K

S

1

1

2

3

4

6

TR TR1

SO

SR

+

+

TR

M7415 ACTUATORW7459A ECONOMIZER PACKAGE

+

C

G

W1

Y1

R

W2

RC

G

X

W1

Y1

W2

C7400ENTHALPY SENSOR

UNOCCUPIED

OCCUPIED

ST6008 TIMER

3

2

51K

4

5

T

6

7

7

8

8 P

T

1S

1S1

MINIMUM POSITIONADJUSTMENT

TR1

MINIMUMPOSITION

MIXEDAIRSENSOR

24 VAC

C7150B MIXED AIR OR C7046ADISCHARGE AIR SENSOR

M7415

TR

TR1

T1

P1P

24 VAC

SENSOR

MINPOS

T

620 OHMRESISTOR


63-2684—01 6

Fig. 5. W7459A/C7400 or W7459D/C7400 used in two-stage cooling system with single enthalpy changeover, and M7415 Actuator.

L1 (HOT)

L2

FDR

FDR

FAN

FANDELAYRELAY

HEAT 1

HEAT 2

COOL 1







FACTORY INSTALLED 620 OHM, 1 WATT, 5% RESISTOR SHOULD BE REMOVED ONLY IF A C7400 ENTHALPY SENSOR IS ADDED TO SR AND + FOR DIFFERENTIAL ENTHALPY.

FOR T7300 ONLY.

WITH T7300, USE CONTACTS A1 AND A2 INSTEAD OF S7005 TIMER. M10115A


T1

P1P1P

T1

1

3 4

2

5

2K

S

1

1

2

3

4

6

TR TR1

SO

SR

+

+

TR


+

C

G

W1

Y1

R

W2

RC

G

X

W1

Y1

Y2

W2

C7400OUTDOORAIR ENTHALPY SENSOR

UNOCCUPIED

OCCUPIED

ST6008TIMER

3

2

51K

COOL 2Y2

4

5

T

6

7

7

8

8 P

T

1S

1S1


TR1

MINIMUMPOSITION

MIXEDAIRSENSOR

24 VAC


M7415

TR

TR1

T1

P1P

24 VAC

SENSOR

MINPOS

T

620 OHMRESISTOR

W

R

T6031 AMBIENT LOCKOUT CONTROL 50 F SETPOINT

RH


7 63-2684—01

Fig. 6. W7459A/C7400 or W7459D/C7400 used in two-stage cooling system with single enthalpy changeover, M7415 Actuator, and T775 Thermostat.

L1 (HOT)

L2

FAN

COOL 1





1S IS AN ELECTRONIC SWITCH, WHICH CLOSES WHEN POWERED BY A 24 VAC INPUT.



T775 REQUIRES A MINIMUM OF THREE RELAY OUTPUTS: TWO FOR COOLING AND ONE FOR FAN CONTROL.A MAXIMUM OF ONE STAGE OF HEATING IS POSSIBLE WHEN THE SYSTEM IS WIRED IN THIS FASHION. M11680A

T1

P1P1P

T1

1

3 4

2

5

2K

S

1

1

2

3

4

6

TR TR1

SO

SR

+

+

TR


+

C

G

Y1

R

C7400OUTDOORAIR ENTHALPY SENSOR

3

2

51K

COOL 2Y2

4

5

T

6

7

7

P

T

1S

1S1


TR1

MINIMUMPOSITION

MIXEDAIRSENSOR

24 VAC


M7415

TR

TR1

T1

P1P

24 VAC

SENSOR

MINPOS

T

620 OHMRESISTOR

W

R


NOCOM

NC

NCCOM

NO

NCCOMNO

T775 CONTROLLER

UNOCCUPIED

OCCUPIED

ST6008TIMER


63-2684—01 8

Fig. 7. W7459A/C7400 or W7459D/C7400 used in one-stage cooling system with differential enthalpy changeover, and M7415 Actuator.

L1 (HOT)

L2

FDR

FDR

FAN

FANDELAYRELAY

HEAT 1

HEAT 2

COOL 1


W

R





RELAYS 1K AND 2K ACTUATE WHEN THE OUTDOOR AIR ENTHALPY IS HIGHER THAN THE ENTHALPY SETPOINT A-D.

FACTORY INSTALLED 620 OHM, 1 WATT, 5% RESISTOR SHOULD BE REMOVED ONLY WHEN A C7400 ENTHALPY SENSOR IS ADDED TO SR AND + FOR DIFFERENTIAL ENTHALPY.

FOR T7300 ONLY.

WITH T7300, USE CONTACTS A1 AND A2 INSTEAD OF A TIMER.

M3864B


T1

P1P1P

T1

1

3 4

2

2K

S

C7400OUTDOORAIRENTHALPYSENSOR

C7400RETURNAIRENTHALPYSENSOR

1

1

2

3

4

TR TR1

SO

SR

+

+

TR


+

C

G

W1

Y1

Y2

R

W2

S

+

RC

G

X

W1

Y1

Y2

W2

RH


UNOCCUPIED

OCCUPIED

ST6008TIMER

3

2

5

5

6

1K

4

5

T

6

7

7

8

8 P

T

1S

1S1


TR1

MINIMUMPOSITION

MIXEDAIR SENSOR

C7150B MIXEDAIR ORC7046A DISCHARGE AIR SENSOR

24 VAC


9 63-2684—01

Fig. 8. W7459A/C7400 or W7459D/C7400 used in T7400/W7400 System with M7415 Actuator.

L1 (HOT)

L2

FDR

3K1

GND

FAN

FANDELAYRELAY

HEAT 1

HEAT 2

COOL 1


W

R

14 23 R






USE R8222N WITH PILOT DUTY CONTACTS FOR 3K. CONTACTS 3K1, 3K2 MAKE WHEN ENTHALPY IS BELOW SETPOINTAND ECONOMIZER IS USED FOR FIRST STAGE OF COOLING.

FACTORY INSTALLED 620 OHM, 1 WATT, 5% RESISTOR SHOULD BE REMOVED ONLY WHEN A C7400 ENTHALPY SENSOR IS ADDED TO SR AND + FOR DIFFERENTIAL ENTHALPY.

M10117A

T7400 THERMOSTATT7400/W7400 SYSTEM

T1

P1P1P

T1

1

3 4

2

5

2K

S

C7400ENTHALPYSENSOR

1

1

2

3

4

TR TR1

SO

SR

+

+

TR


+

C

G

W1

Y1

Y2

R

W2

T6031 LOCKOUT 50 F SETPOINT

3

2

6

5

7

61K

COOL 2

4

5

T

6

6

7

P

T

1S

1S1


TR1

MINIMUMPOSITION

MIXEDAIR SENSOR

C7150B MIXEDAIR ORC7046A DISCHARGE AIR SENSOR

T7400B ONLY;T7047C1025 ORT7022A1010REMOTE SENSOR

W7400 CONTROL MODULE

620 OHMRESISTOR

3K RELAY

TR

TR

RHRC

4

3

2

1

24 VAC

3K2

T7400

A

COM

B

ECONO.AUXRELAY

ENTHALPYSWITCH

6

5

RC G

RH W1

W2

Y1

Y2

RC

1

WALLPLATE OR Q7400 SUBBASE

24 VAC


63-2684—01 10

Fig. 9. W7459B/C7400 used in two-stage cooling system with single enthalpy changeover, and M7405 Actuator.

L1 (HOT)L2

M7405

TR

TR1

M3

M1

P1P

24 VAC

W7401

MINPOS

M2

R

C

G

W1

W2

Y1

Y2

RC

TR

G

W1

W2

Y1

Y2

T

T1

6

M1

FDR

FDR

FAN

FANDELAYRELAY

HEAT 1

HEAT 2

COOL 1

COOL 2


W7401 LOGICPANEL

TR

RH

1

2

3

4

M2

M3

5



RELAY 1K ACTUATES WHEN THE ENTHALPY SENSED BY THE C7400 IS HIGHER THAN THE ENTHALPY SETPOINT A-D. M3863

T7400 PROGRAMABLETHERMOSTAT

C7046ADISCHARGE AIR LOW LIMIT SENSOR

24 VAC

P1

P

M2

M1

M3

MINIMUMPOSITION

24 VAC


P1P

M2 M1

M3

2 1

3

1K

S

C7400ENTHALPYSENSOR

620 OHMRESISTOR

1

1

2

3

2

3

TR TR1

SO

SR

+

+

TR1

TR

M7405 ACTUATORW7459B ECONOMIZER PACKAGE

1

2

3

4

+


11 63-2684—01

Fig. 10. W7459C/C7400 used in two-stage cooling system with differential enthalpy changeover, and M8405 Actuator.

Optional Applications

Remote Minimum Position ControlRemote control of outdoor air dampers is desirable when potential exists for temporary additional ventilation. The potentiometer in W7459 controls damper minimum position.

Adding S963B1128 Remote Manual Potentiometer allows occupants to open dampers beyond minimum position for additional ventilation. Connect potentiometer as shown in Fig. 11.

L1 (HOT)

L2

M8405

T

D

APPLY 24VAC T-XFOR MIN POSNT-D FOR MAX POSN

FDR

FDR

FAN

FANDELAYRELAY

HEAT 1

HEAT 2

COOL 1

COOL 2


W

R






FOR T7300 ONLY.

TR1 IS HOT ON W7459C. TR1 IS GROUND ON ALL OTHER MODELS OF W7459. M29167


X

DD6

X

1

3 4

5

2

2K

S

C7400OUTDOORSENSOR

1

1

2

3

4

TR TR1

SO

SR

+

+

T

M8405ACTUATORW7459C ECONOMIZER PACKAGE

+

C

G

W1

Y1

Y2

R

W2

WR

SC7400RETURNSENSOR +

RC

G

X

W1

Y1

Y2

W2

RH

T675/T6031 MIXED AIR CONTROL 55°F SETPOINT

T6031 AMBIENT LOCKOUT CONTROL 50°F SETPOINT

UNOCCUPIED

OCCUPIED

ST6008TIMER

3

2

5

1K

4

5

6

6

MAX

SWSET

MIN

X

7

7


63-2684—01 12

Fig. 11. S963B1128 Remote Minimum Position Potentiometer used with W7459 for remote damper

control.

SETTINGS AND ADJUSTMENTS

Potentiometers with screwdriver adjustment slots, located on face of device, provide adjustments for minimum damper position and enthalpy changeover. See Fig. 12.

Fig. 12. Location of enthalpy setpoint potentiometer, minimum position potentiometer and LED.

Adjusting Minimum Damper PositionMinimum position potentiometer keeps outdoor air damper from closing completely during system operation to provide ventilation.

Minimum Position Adjustment W7459A and W7459D

1. Disconnect mixed air sensor from terminals T and T1.2. Make sure either factory-installed jumper is in place

across terminals P and P1 or if remote damper posi-tioner is required, that it is wired according to Fig. 11 and turned fully clockwise.

3. Connect 24 Vac across terminals TR and TR1.4. Adjust potentiometer on face of W7459 with screwdriver

to desired minimum position.

W7459B1. Make sure either the factory-installed jumper is in place

across terminals P and P1 or if remote damper posi-tioner is required, that it is wired according to Fig. 11 and turned fully clockwise.

2. Connect jumper across terminals M1 and M3.

IMPORTANTDo not contact or connect jumper to M2. If M2 is jum-pered to M1, the motor will not respond to the control-ler.

3. Connect 24 Vac across terminals TR and TR1.4. Adjust potentiometer on face of W7459 with screwdriver

to desired minimum position.

W7459C1. Connect 24 Vac at terminals TR and X.

NOTE: Ensure that terminal D is not connected.

2. Adjust thumbwheel on motor for desired minimum posi-tion.

Outdoor Enthalpy Changeover SetpointThe outdoor enthalpy changeover setpoint is used to return the outdoor air damper to minimum position when enthalpy rises above setpoint. Enthalpy setpoint scale markings, located on W7459, are A, B, C, and D; see Fig. 13 for corresponding control point. The factory-installed 620 ohm jumper must be in place across terminals SR and +.

Differential Enthalpy Changeover SettingDifferential enthalpy control uses two C7400 Solid State Enthalpy Sensors connected to one W7459 Economizer Control. The economizer compares outdoor air to the return air instead of to a set point (as with single enthalpy). Turn enthalpy setpoint potentiometer fully clockwise [cw arrow] to D setting. The economizer selects the lower enthalpy air (return or outdoor) for cooling; for example, when outdoor air has lower enthalpy than return air, the outdoor air damper opens to bring in outdoor air for free cooling.

M10116A

P1P

W7459A,B,D ECONOMIZER PACKAGE

R


W B

CWCLOSE

CCWOPEN

S963B1128 REMOTEMINIMUM POSITIONPOTENTIOMETER

135 OHM

OPEN

1

1M9098B

ENTHALPYCHANGEOVERSETPOINT

MINIMUM DAMPERPOSITION SETTING

LED LIGHTSWHEN OUTDOOR AIR IS SUITABLE FOR FREE COOLING

MINIMUM DAMPER POSITION ADJUSTMENT IS PRESENT ONLY ON W7459A,D MODELS.


13 63-2684—01

Fig. 13. W7459/C7400 performance characteristics for enthalpy changeover settings.

High Enthalpy LimitW7459D Economizer Logic Module has a high outdoor air enthalpy limit feature when used in differential enthalpy mode. The limit feature prevents using high enthalpy outdoor air when return air enthalpy is higher than outdoor air. See Table 2 in the Specifications section.

OPERATION

Integrated Economizer System Single (Outdoor) EnthalpyThe purpose of an economizer is to use outdoor air for cooling whenever possible, to reduce compressor operation. The W7459 Economizer System, when wired as shown in Fig. 4 through 10, responds to a signal from the cooling thermostat. This system uses the C7400 Solid State Enthalpy Changeover Sensor or the C7660 Solid State Dry Bulb Temperature Sensor. The C7400 responds to both dry bulb temperature and

humidity, allowing use of outdoor air at higher temperatures for free cooling when humidity is low. The C7660 responds to only dry bulb temperature and should be used only in dry, arid climates and in single enthalpy applications.

The economizer functions as a true first stage of cooling and provides maximum fuel economy during the cooling cycle. The economizer is automatically locked out during heating. It holds the outdoor air damper at the minimum position setting.

On a call for cooling by the space thermostat, the system operates as follows:

OUTDOOR AIR ENTHALPY IS BELOW SETPOINT1. The outdoor air damper is proportioned open (and the

return air damper is proportioned closed) to maintain between 50°F and 56°F at the mixed/discharge air sen-sor.

2. During economizer operation, mechanical cooling is operated by the second stage of cooling on the space thermostat.

CONTROLCURVE

ABCD

CONTROL POINTAPPROX. °F (°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

60

50

40

30

20

10

ENTHALP

Y—BTU

PER P

OUND D

RY 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)

APPROXIMATE DRY BULB TEMPERATURE—°F (°C)

A

A

B

B

C

C

D

D

M11681

RE

LATI

VE

HU

MID

ITY

(%)

1

1

HIGH LIMIT CURVE FOR W7459D.


63-2684—01 14

OUTDOOR AIR ENTHALPY IS ABOVE SETPOINT1. The outdoor air damper closes to its minimum position.2. A call for cooling from the space thermostat brings on

mechanical cooling.3. During the unoccupied period, the actuator spring return

moves the outdoor air damper to the fully closed posi-tion.

NOTE: See Fig. 3 for representative locations of economizer system devices.

CHECKOUT AND TROUBLESHOOTING

Check the W7459 for proper operation. Table 3 through 5 describe how to simulate various environmental conditions. Make necessary minor adjustments to the minimum position until desired operation is obtained.

If the economizer system does not operate properly, check individual components of the system according to the instructions provided with each device.

If the other components operate properly when disconnected from the W7459, but the system (as a whole) does not, replace the W7459.

CAUTIONEquipment Damage Hazard.Excessive force can damage controls.Use a small screwdriver when adjusting enthalpy changeover and minimum damper position controls.

To check motor, jumper T to T1 to bypass the mixed air sensor.

Table 3. Troubleshooting procedure for W7459A or W7459D Economizer Installed on M7415 Actuator.

Checkout Procedure Proper Response

1. a. Disconnect power at TR and TR1. —

b. Disconnect Jumper P to P1.

c. Jumper TR to 1.

d. Jumper T1 to T.

e. If connected, remove C7400 Solid State Enthalpy Sensor from terminals SO and +. Ensure factoryinstalled 620 ohm resistor is connected to terminals SR and +.

LED is off.

f. Apply power (24 Vac) to terminals TR and TR1. Motor is in closed position.

2. a. Disconnect factory-installed 620 ohm resistor from terminals SR and +.

LED turns on (on A model only, for D model, go to step 3)Motor drives toward open.

3. a. To simulate high and low enthalpy (single enthalpy sensor), reconnect factory-installed 620 ohm resistor from terminals SR and +. Connect 1.2K ohm 4074EJM Checkout Resistor across terminals SO and +.

—

b. Turn enthalpy setpoint potentiometer to “A”. LED turns on, indicating low enthalpy. Motor drives toward open.

c. Turn enthalpy setpoint potentiometer to “D”. LED turns off, indicating high enthalpy. Motor drives toward closed.

d. Disconnect the 1.2K ohm checkout resistor. —

4. a. To verify sensor operation, reconnect the + lead of outdoor enthalpy sensor to the + terminal of W7459.

b. Connect a DC milliammeter between terminal SO of the W7459A and terminal S of the enthalpy sensor. See Fig. 14 (positive meter lead to terminal S of the enthalpy sensor).

Milliammeter indication is between 3 and 25 mA if sensor is operating properly. If milliammeter indicates zero, the sensor may be wired backward.

c. When using differential enthalpy, check the return air enthalpy sensor by connecting a DC milliammeter between terminal SR of the W7459A and terminal S of the return air enthalpy sensor. (Positive meter lead to terminal S of the enthalpy sensor.)



15 63-2684—01

Fig. 14. Meter location for checkout and troubleshooting.

1

1

2

2

M9097

ENTHALPY CHANGEOVERSETPOINT

LED LIGHTS WHENOUTDOOR AIR IS SUITABLE FOR FREE COOLING

INSERT DC MILLIAMMETER BETWEEN SO AND S FOR CHECKOUT AND TROUBLESHOOTING.

JUMPER USED FOR SINGLE ENTHALPY CONTROL.

TR TR1

A

B C

DSO

SR

+

+

+

C7400

620 OHMJUMPER

DC MILLIAMMETER

W7459

S

+

Table 4. Troubleshooting procedure for W7459B Economizer installed on M7405 Actuator.

Checkout ProcedureProper Response


b. Disconnect Jumper P to P1.

c. Jumper M1 to 3.

d. Jumper M2 to 2. M3 remains unconnected.

e. If connected, remove C7400 Solid State Enthalpy Sensor from terminals SO and +. Ensure factoryinstalled 620 ohm resistor is connected to terminals SR and +.

LED is off.


2. a. Disconnect factory-installed 620 ohm resistor from terminals SR and +.

LED turns on.Motor drives toward open.

3. a. To simulate high and low enthalpy (single enthalpy sensor), reconnect factory-installed 620 ohm resistor from terminals SR and +. Connect 1.2K ohm 4074EJM Checkout Resistor across terminals SO and +.

—

b. Turn enthalpy setpoint potentiometer to A. LED turns on, indicating low enthalpy. Motor drives toward open.

c. Turn enthalpy setpoint potentiometer to D. LED turns off, indicating high enthalpy. Motor drives toward closed.


4. a. To verify sensor operation, reconnect the + lead of outdoor enthalpy sensor to the + terminal of W7459.

—

b. Connect a DC milliammeter between terminal SO of the W7459B and terminal S of the enthalpy sensor. See Fig. 14 (positive meter lead to terminal S of the enthalpy sensor).

Milliammeter indication is between 3 and 25 mA if sensor is operating properly.If milliammeter indicates zero, the sensor may be wired backward.

c. When using differential enthalpy, check the return air enthalpy sensor by connecting a DC milliammeter between terminal SR of the W7459B and terminal S of the return air enthalpy sensor. (Positive meter lead to terminal S of the enthalpy sensor.)

Milliammeter indication is between 3 and 25 mA if sensor is operating properly.If milliammeter indicates zero, the sensor may be wired backward.

Automation and Control Solutions

Honeywell International Inc. Honeywell Limited-Honeywell Limitée

1985 Douglas Drive North 35 Dynamic Drive

Golden Valley, MN 55422 Toronto, Ontario M1V 4Z9

customer.honeywell.com


® U.S. Registered Trademark© 2009 Honeywell International Inc.63-2684—01 M.S. 02-09

Table 5. Troubleshooting procedure for W7459C Economizer installed on M8405 Actuator.

Checkout Procedure Proper Response


b. Disconnect wires from terminals 6, X and D.

c. Jumper TR1 to 1.

d. Jumper 6 to D.

e. If connected, remove C7400 Solid State Enthalpy Sensor fromterminals SO and +. Ensure factoryinstalled 620 ohm resistor is connected to terminals SR and +.

LED is off.


2. a. Disconnect factory-installed 620 ohm resistor from terminals SRand +.

LED turns on. Motor drives toward open.

3. a. To simulate high and low enthalpy (single enthalpy sensor),reconnect factory-installed 620 ohm resistor from terminals SR and +. Connect 1.2K ohm 4074EJM Checkout Resistor across terminals SO and +.

—

b. Turn enthalpy setpoint potentiometer to A. LED turns on, indicating low enthalpy. Motor drives toward open.

c. Turn enthalpy setpoint potentiometer to D. LED turns off, indicating high enthalpy. Motor drives toward closed.


4. a. To verify sensor operation, reconnect the + lead of outdoorenthalpy sensor to the + terminal of W7459.

—

b. Connect a DC milliammeter between terminal SO of the W7459Cand terminal S of the enthalpy sensor. See Fig. 14 (positive meter lead to terminal S of the enthalpy sensor).


c. When using differential enthalpy, check the return air enthalpysensor by connecting a DC milliammeter between terminal SR of the W7459C and terminal S of the return air enthalpy sensor (positive meter lead to terminal S of the enthalpy sensor).


By using this Honeywell literature, you agree that Honeywell will have no liability for any damages arising out of your use or modification to, the literature. You will defend and indemnify Honeywell, its affiliates and subsidiaries, from and against any liability, cost, or damages, including attorneys’ fees, arising out of, or resulting from, any modification to the literature by you.

63-2684—01 - W7459A,B,C,D Solid State …B,C,D SOLID STATE ECONOMIZER™ LOGIC MODULE 63-2684—01...

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