
Economizer Sensors
C7400A,C Enthalpy Sensor
The C7400A Enthalpy Sensor is used with the economizer logic 
modules with the A,B,C, and D performance curves; the C7400C 
sensor is used with the logic modules with the 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 air conditioning (HVAC) 
systems.
Application: Enthalpy economizing 
Dimensions, Approximate: 4.25 in high x 2.17 in wide x .81 in deep 
(108 mm high by 55mm wide x 20.5 mm deep) 
Sensor Type: 4-20 mA output 
Color: Gray 
Mounting: Mounted in any position where it is exposed to freely circulating air.
Product Number Application Type
C7400A2001/U A solid state enthalpy sensor designed to sense 
temperature and humidity with 5% accuracy
C7400C2007/U A solid state enthalpy sensor designed to sense 
temperature and humidity with 5% accuracy
• Senses and combines temperature and humidity of outdoor air.
• As enthalpy of outdoor air increases, the outdoor air damper 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 economizer 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 duct mounting 
• Sensors are enclosed in a rugged, corrosion-resistant glass-fiber 
reinforced plastic duct-mount case.
• Provides a 4 to 20 mA output signal to Economizer Logic Module; 
setpoint is located on the logic module.
Operating Temperature Range: 
Operating Humidity Range (% RH): 11 to 89% RH 
Electrical Connections: Two 1/4 in. quick-connect terminals
Approvals 
Underwriters Laboratories, Inc: Component Recognized
Maximum 
Ambient 
Tem peratur e
Description Used With(F) (C)
150 F 66 C Solid State Enthalpy 
150 F 66 C Solid State Enthalpy 
Sensor
Sensor
kit is available.
-40 F to 150 F (-40 C to 66 C) 
W7210, W7212A, W7213, W7214, 
W7215, W7459, W7460
W7210, W7212A, W7213, W7214, 
W7215, W7459, W7460
C7400S Enthalpy Sensor
A separate controller such as the JADE™ Economizer System 
(Model W7220) provides power and communications on the Sylk 
Bus for the C7400S Sylk Bus sensor.
• This unit mounted C7400S enthalpy sensor includes solid state 
temperature and humidity sensors.
• Outputs a digital communicating signal on a two-wire Sylkbus 
communications link, reporting the temperature and humidity 
separately to the controller.
• The controller determines the enthalpy (total heat), enabling 
economizer modes of operation when outside air enthalpy is suitable 
for free cooling.
The C7400S Sylk Bus sensor is a combination temperature and 
humidity sensor, which is intended to be used in commercial roof 
top units for sensing air. The sensor is powered by and 
communicates on the Sylk Bus. The C7400S communicates 
temperature and humidity separately digitally on the Sylk Bus 
Communication Protocol.
Application: Provides Honeywell SYLK Bus signal in relation 
to enthalpy - 5% accuracy
Dimensions, Approximate: 4.25 in high x 2.17 in wide x .81 in deep 
(108 mm high by 55mm wide x 20.5 mm deep) 
Sensor Type: 7-21Vdc 
Color: Gray 
Mounting: 
Operating Temperature Range: 
Product Number Application Type
C7400S1000/U A solid state enthalpy sensor designed to sense temperature and 
Mounted in any position where it is exposed to freely circulating air.
humidity with 5% accuracy. Use with W7220 economizer control, 
for use in outdoor air intakes of HVAC rooftop
-40 F to 150 F (-40 C to 66 C) 
• Enthalpy sensors are compatible with Honeywell economizer 
systems.
• When used with an economizer, the enthalpy boundary curve is 
programmed via the controller. When the temperature and humidity 
are determined to be suitable based on the relationship to the 
boundary, the controller allows outside air for economizing.
• Dual enthalpy sensors in outside air and return switches the 
controllers to economizer mode of operation anytime the outside 
enthalpy is less than the return air enthalpy.
Operating Humidity Range (% RH): 11 to 89% RH 
Electrical Connections: 2-pin header-pin style or 2-pin card edge 
removable terminal blocks
Approvals 
Underwriters Laboratories, Inc: Component Recognized Guide info 
XAPX)
Maximum Ambient 
Temperature
Description Used With(F) (C)
150 F 65 C Solid State 
Enthalpy Sensor
W7220
410 customer.honeywell.com 70-6910