Bryant 604D--A installation instructions 604D-- --A, Connect 24 vac across terminals TR and TR1

604D-- -- A

When demand ventilation control is not being used, the minimum position potentiometer should be used to set the occupied ventilation position. The maximum demand ventilation position should be turned fully clockwise. Adjust the minimum position potentiometer to allow the minimum amount of outdoor air, as required by local codes, to enter the building. Make minimum position adjustments with at least 10_F (12.2_C) temperature difference between the outdoor and return-air temperatures. To determine the minimum position setting, perform the following procedure:

1.Calculate the appropriate mixed air temperature using the following formula:

(To x OA/100) + (TR x RA/100) = TM TO = Outdoor-Air Temperature

OA = Percent of Outdoor Air TR = Return-Air Temperature RA = Percent of Return Air TM = Mixed-Air Temperature

As an example, if local codes require 10% outdoor air during occupied conditions, outdoor-air temperature is 60_F (15.6_C), and return-air temperature is 75_F (23.9_C). (60 x .10) + (75 x .90) = 73.5_F (23.1_C)

2.Disconnect the supply air sensor from terminals T and T1.

3.Ensure that the factory-installed jumper is in place across terminals P and P1. If remote damper positioning is being used, make sure that the terminals are wired according to Fig. 44 and that the minimum position potentiometer is turned fully clockwise.

4.Connect 24 vac across terminals TR and TR1.

5.Carefully adjust the minimum position potentiometer until the measured mixed-air temperature matches the calculated value.

6.Reconnect the supply air sensor to terminals T and T1.

Remote control of the Economizer damper is desirable when requiring additional temporary ventilation. If a field-supplied remote potentiometer (Honeywell part number S963B1128) is wired to the Economizer controller, the minimum position of the damper can be controlled from a remote location. To control the minimum damper position remotely, remove the factory installed jumper on the P and P1 terminals on the Economizer controller. Wire the field-supplied potentiometer to the P and P1 terminals on the Economizer controller. See Fig. 43 and Fig. 44.

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