Honeywell W7340 Manual Do Utilizador

9

63-2569—04

On the W7340A and B models, the logic module as shipped 

from the factory, limits the minimum position setpoint to 50%. 

The logic module will not allow a minimum position greater 

than 50% open (from fully closed).

NOTE: This setpoint limit can only be changed using a 

Modbus command.

 or 

Where:

T

O

 = Outdoor air temperature

OA = Percent of outdoor air

T

R

 = Return air temperature

RA = Percent of return air

T

M

 = Resulting mixed air temperature

NOTE: The following sample calculation uses only 

Fahrenheit temperature.

EXAMPLE: Assume local codes require 10% outdoor air 

during occupied conditions, outdoor air is 60° F 

and return air is 75° F. Under these conditions, 

what is the temperature of the mixed air?

 or

 

Mixed air will be 73.5° F when OA is 60° F and RA is 75° F with 

10 percent outdoor air entering the building.

NOTE: The W7340C model min position and DCV min must 

be set in the field by the installer. See Section DCV 

Min and Min Position Damper Set up.

The outdoor enthalpy changeover setpoint returns the outdoor 

air damper to minimum position when enthalpy rises above its 

setpoint. Enthalpy setpoint scale markings, located on the 

device, are A, B, C, D and E. See Fig. 10 for the corresponding 

control point.

Differential enthalpy control uses:

— W7340A and B use two C7400A Enthalpy Sensors 

connected to one logic module, or

— Two 10K NTC temperature sensors and two C7600C 

Humidity Sensors connected to one logic module.

— W7340C uses C7400C Enthalpy Sensor(s) or

— Two 10K NTC temperature sensors and two C7600C 

Humidity Sensors connected to one logic module.

With outdoor and return air sensors, the logic module 

compares outdoor air to return air instead of to a setpoint as it 

does for single enthalpy. The logic module 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.

NOTE: When using the W7340 for differential enthalpy, keep 

the setpoint potentiometer set at D.

The exhaust setpoint determines when the exhaust fan will run 

based on the damper position.

The logic module, as shipped from the factory, uses an 

exhaust setpoint of 25%. When the damper position is greater 

than 25% open (from fully closed), relay contact for the 

exhaust fan is closed. When the damper position is below 22% 

open, the relay is de-energized.

The W7340 can be configured for humidity or enthalpy 

sensors. Configuration can be performed manually or over the 

Modbus.

To configure the W7340 manually:

1. Within the first three minutes after powering the device, 

short the external minimum damper position terminals 

(P-P1).

NOTE: The LED will go solid within five seconds of 

shorting these terminals.

2. Maintaining the short for another five seconds causes 

the LED to flash quick pulses (between off periods) 

indicating the sensor configuration type:

a. Two quick pulses: Humidity.

b. Three quick pulses: Enthalpy.

3. To toggle the sensor configuration type:

a. Remove the short until the LED goes solid again.

b. Reapply the short for another five seconds.

NOTE: Once the short is removed for over 10 seconds, 

the device saves the most recent configuration.

OA

×

(

)

RA

×

(

)

+

=

–

(

)

OA T

+

×

=

0.1x6° F

(

)

0.9x75° F

(

)

+

6.0° F 67.5° F

+

73.5° F

=

=

60° F 75° F

–

(

)

0.1 75° F

+

×

1.5

–

75° F

+

73.5° F

=

=