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C7400A and C7400C

PRODUCT DATA FEATURES

• Senses and combines and of outdoor air. • As enthalpy of outdoor air increases, the outdoor air closes to a preset minimum position. • As enthalpy of outdoor air becomes low, the outdoor air damper opens to reduce the mechanical cooling load in the building. • Maximum savings is achieved when two C7400 Enthalpy Sensors are used for differential enthalpy changeover control. • Compact size and lightweight construction allows easy mounting in HVAC rooftop unit. A mounting kita is available. APPLICATION • Sensors are enclosed in a rugged, corrosion-resistant -fiber reinforced plastic duct-mount case. The C7400A Enthalpy is used with the economizer logic modules with the A,B,C, and D performance curves; the • Provides a 4 to 20 mA output signal to Economizer C7400C sensor is used with the logic modules with the Logic Module; setpoint is located on the logic module. A,B,C,D, and E performance curves. The sensors combined with the economizer logic modules permit the use of outdoor air as the first stage of cooling in heating, ventilating and (HVAC) systems. a part number 50053060-001

Contents Application ...... 1 Specifications ...... 2 Installation ...... 2 Ordering Information ...... 2 Operation ...... 4

63-2140-13 C7400A AND C7400C ENTHALPY SENSORS

SPECIFICATIONS INSTALLATION

Models: C7400A enthalpy sensor for use with economizer logic When Installing this Product... modules with A,B,C, and D performance curves. 1. Read these instructions carefully. Failure to follow them C7400C enthalpy sensor for use with economizer logic could damage the product or cause a hazardous condi- modules with A,B,C,D, and E performance curves. tion. 2. Check the ratings given in the instructions and on the Dimensions: product to make sure the product is suitable for your C7400A2xxx and C7400C2xxx – See Fig. 1. application. Output Signal:4 to 20 mA current signal increases from 4 mA 3. Installer must be a trained, experienced service techni- to 20 mA as enthalpy decreases. cian. 4. After installation is complete, check out product opera- Ambient Temperature Ranges: tion as provided in these instructions. Shipping: -40°F to 150°F (-40°C to 66°C) 5. Verify polarity of wiring connections from sensor to logic Operating: module are correct. C7400A2xxx and C7400C2xxx: -40ºF to 150ºF (-40ºC to 65.6ºC) NOTE: Maximum torque for the mounting screws is 17.7 lb-in (2 Nm) Maximum Consumption: C7400A2xxx and C7400C2xxx: 3.5mA minimum @ 40 Vdc-20 mA: 0.8 VA maximum CAUTION Supply (all models): Electrical Shock or Equipment Damage Hazard. C7400A2xxx and C7400C2xxx: 12 to 40 Vdc Can shock individuals or short equipment circuitry. Electrical Connections: Disconnect power supply before installation. Two 1/4 in. (6 mm) quick connect terminals. Follow specific installation instructions furnished by the HVAC Approvals: equipment manufacturer. If not available, use this procedure. Underwriters Laboratories Inc. Flammability Rating: UL94-5V.

51/64 (21)

4-1/4 (108) 2-3/4 (70)

2-1/64 (55)

M32331

Fig. 1. Approximate dimensions of C7400A2xxx and C7400C2xxx Enthalpy Sensors in inches (mm).

ORDERING INFORMATION

When purchasing replacement and modernization products from your TRADELINE® wholesaler or , 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 Environmental and Controls Sales Office (check white pages of your phone directory). 2. Honeywell Customer Care 1985 Douglas Drive North Minneapolis, Minnesota 55422-4386 3. http://customer.honeywell.com or http://customer.honeywell.ca International Sales and Service Offices in all principal cities of the world. in Belgium, Canada, China, Czech Republic, Germany, Hungary, Italy, Mexico, Netherlands, United Kingdom, and United States.

63-2140—13 2 C7400A AND C7400C ENTHALPY SENSORS

Location — Differential enthalpy control requires two C7400 Sensors. Mount one sensor in the outdoor intake IMPORTANT duct, the other in the return air duct. When selecting the location, make sure the C7400 — The C7400 Sensor is designed to operate in Enthalpy Sensor is not exposed to rain, snow or direct 500 ft./min. minimum airflow. sunlight. Wiring NOTES: — The C7400 Sensor can be mounted in any IMPORTANT position. However, the sensor must be installed All wiring must agree with applicable codes, where it is exposed to freely circulating air, but pro- ordinances and regulations. tected from rain, snow and direct sunlight. Follow the wiring information furnished by the HVAC equipment manufacturer or see Fig. 2 for typical wiring hookups.

W7459 ECONOMIZER PACKAGE MOUNTED ON ACTUATOR

L1 TR 1 (HOT) TR 24 Vac TR1 TR1 L2 BC 5 SO + A D ENTHALPY + SETPOINT SR + S 2 5 OUTDOOR AIR ENTHALPY SENSOR C7400A 1 2

3 T + 3 4 MINIMUM MIXED AIR 4 T1 S POSITION SENSOR T T1 RETURN AIR ENTHALPY SENSOR C7400A P1 P OPEN MINIMUM P1 P POSITION

W7459 ECONOMIZER PACKAGE ACTUATOR

1 PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.

2 CONNECT C7400 ENTHALPY SENSOR TO TERMINALS SR AND + FOR DIFFERENTIAL ENTHALPY CONTROL. REMOVE 620 OHM AND MOUNT THE SECOND C7400 ENTHALPY SENSOR IN RETURN AIR.

3 SEE LOGIC MODULE SPECIFICATION FOR ADDITIONAL WIRING INFORMATION.

4 VERIFY POLARITY OF WIRING TO LOGIC MODULE IS CORRECT.

5 USE C7400A SENSOR WITH A,B,C, AND D PERFORMANCE CURVE LOGIC MODULES AND USE C7400C SENSOR WITH A,B,C,D AND E PERFORMANCE CURVE LOGIC MODULES. M27817

Fig. 2. Wiring connections for C7400 Enthalpy Sensors.

3 63-2140—13 C7400A AND C7400C ENTHALPY SENSORS

OPERATION

Controller Dial Setting C7400A OUTPUT CURRENT Control setpoint scale is located on the logic modules. Control 100 points (A,B,C,D, and E) are field selectable and are used for single enthalpy sensing. Turn to D or E (fully clockwise ) 90 when differential enthalpy control is desired. When differential enthalpy control is desired, two enthalpy sensors must be 80 connected to the economizer logic module. See Fig. 2 on page 3. 70

60 20 mA 16 mA 12 mA Operation 8 mA 4 mA

18 mA 14 mA 10 6 mA

The C7400 Enthalpy Sensor is used with an economizer logic 50 m A module and damper actuator to proportion an outdoor air PERCENT RF damper in a ventilation system. 40 Each enthalpy control setpoint (A,B,C, and D) or (A,B,C,D, and E) combines temperature and humidity conditions, resulting in 30 the control curve shown in Fig. 5 and 6. When the enthalpy of the outdoor air is below (left of) the appropriate curve, the 20 outdoor air damper can proportion open on a call for cooling from the space . If the outdoor enthalpy rises above 10 40 50 60 70 80 90 100 (right of) the control curve, the outdoor air damper closes to the (4) (10) (16) (21) (27) (32) (38) minimum position. TEMPERATURE F ( C) M22117

NOTE: Curves illustrate reset in temperature control Fig. 3. C7400A Sensor output current versus RH. point due to changes in relative humidity.

For differential enthalpy, turn the control setpoint to D or E (fully C7400C SENSOR OUTPUT CURRENT clockwise ): 100 — If outdoor air enthalpy is lower than return air enthalpy, the outdoor air damper proportions open on a call for cooling. 90 — If outdoor air enthalpy is higher than return air enthalpy, the outdoor air damper closes to minimum position. Differential 80 enthalpy control provides savings and increased comfort by using the air with the lowest enthalpy. 70 — If outdoor air enthalpy and return air enthalpy are equal, the

60 20 mA 18 mA 16 mA 14 mA 12 mA 10 mA outdoor air damper proportions open on a call for cooling. 8 mA 6 mA 4 mA

NOTE: The relationship between the C7400 Sensor out- 50

put current and relative humidity is shown in Fig. PERCENT RF 3 and 4. 40

30

20

10 40 50 60 70 80 90 100 (4) (10) (16) (21) (27) (32) (38)

TEMPERATURE ºF ( ºC) M27816

Fig. 4. C7400C Sensor output current versus RH.

63-2140—13 4 C7400A AND C7400C ENTHALPY SENSORS

85 90 95 100 105 110 (29) (32) (35) (38) (41) (43)

CONTROL CONTROL POINT CURVE APPROX. °F (°C) 44 46 AT 50% RH 80 (27) A 73 (23) B 70 (21)

C 67 (19) (%) D 63 (17) AIR 75 D DRY (24)

70 (21) RELATIVE HUMIDITY

100 65 90 80 ENTHALPY—BTU PER POUN (18) 70

60 60 (16) 50 A 40 55 (13) B 30 50 (10) C 20 45 12 14 16 18 20 22 24 26 28 30 D 32 34 36 38 40 42 (7) 40 (4) 10 35 (2)

1 B A D C

35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 (2) (4) (7) (10) (13) (16) (18) (21) (24) (27) (29) (32) (35) (38) (41) (43) APPROXIMATE DRY BULB TEMPERATURE— °F (°C) 1 HIGH LIMIT CURVE FOR W7210D, W7212, W7213, W7214, W7340B. M11160C

Fig. 5. Partial psychrometric chart with single C7400A Enthalpy Sensor and A,B,C, and D Logic Module performance Curves.

5 63-2140—13 C7400A AND C7400C ENTHALPY SENSORS

85 90 95 100 105 110 (29) (32) (35) (38) (41) (43)

CONTROL CONTROL POINT CURVE APPROX. °F (°C) AT 50% RH 80 (27) A 73 (23) B 70 (21) C 67 (19) D 63 (17) Y AIR 38 40 42 44 46 E 55 (13) 75 (24)

70 (21) RELATIVE HUMIDITY (%)

100 65 90 80 ENTHALPY—BTU PER POUND DR (18) 70

60 60 (16) 50 A 40 55 (13) B 30 50 (10) C 20 45 12 14 16 18 20 22 24 26 28 30 D 32 34 36 (7) 40 (4) E 10 35 (2)

1 B A D C E

35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 (2) (4) (7) (10) (13) (16) (18) (21) (24) (27) (29) (32) (35) (38) (41) (43) APPROXIMATE DRY BULB TEMPERATURE— °F (°C) 1 HIGH LIMIT CURVE FOR W7210D, W7212, W7213, W7214, W7340C. M23879A

Fig. 6. Partial psychrometric chart with single C7400C enthalpy sensor and the A,B,C,D, and E logic module performance curves.

63-2140—13 6 C7400A AND C7400C ENTHALPY SENSORS

7 63-2140—13 C7400A AND C7400C ENTHALPY SENSORS

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Automation and Control Solutions Honeywell International Inc. 1985 Douglas Drive North ® U.S. Registered Trademark Golden Valley, MN 55422 © 2012 Honeywell International Inc. 63-2140—13 M.S. Rev. 08-12 customer.honeywell.com Printed in United States