Bryant 580J*04--12 appendix Exhaust Setpoint Adjustment, Minimum Position Control

N1			EXH	TR	TR1
	N		Set
		2V	10V
P1		EXH		24	24 Vac
				Vac	COM
	P
			Min	HOT	_
T1			Pos	+

T Open

		DCV	1	2
		Max
	2V	10V
AQ1	DCV			5
AQ		DCV		4
SO+		Set	3
SO	2V	10V
SR+	Free		EF	EF1
	Cool
SR	B	C
	A	D

C06038

Fig. 50 - EonoMi$er IV Control

Indoor Air Quality (IAQ) Sensor Input

The IAQ input can be used for demand control ventilation control based on the level of CO2 measured in the space or return air duct.

Mount the accessory IAQ sensor according to manufacturer specifications. The IAQ sensor should be wired to the AQ and AQ1 terminals of the controller. Adjust the DCV potentiometers to correspond to the DCV voltage output of the indoor air quality sensor at the user-determined setpoint. (See Fig. 51.)

CO2 SENSOR MAX RANGE SETTING

	6000
(ppm)	5000
CONFIGURATION	4000						800 ppm
	3000						900 ppm
							1000 ppm
	2000						1100 ppm
RANGE	1000
	0
	2	3	4	5	6	7	8
	DAMPER VOLTAGE FOR MAX VENTILATION RATE

C06039

Fig. 51 - CO2 Sensor Maximum Range Settings

If a separate field-supplied transformer is used to power the IAQ sensor, the sensor must not be grounded or the EconoMi$er IV control board will be damaged.

When using demand ventilation, the minimum damper position represents the minimum ventilation position for VOC (volatile organic compounds) ventilation requirements. The maximum demand ventilation position is used for fully occupied ventilation.

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.

Exhaust Setpoint Adjustment

The exhaust setpoint will determine when the exhaust fan runs based on damper position (if accessory power exhaust is installed). The setpoint is modified with the Exhaust Fan Setpoint (EXH SET) potentiometer. (See Fig. 45.) The setpoint represents the damper position above which the exhaust fans will be turned on. When there is a call for exhaust, the EconoMi$er IV controller provides a 45 ± 15 second delay before exhaust fan activation to allow the dampers to open. This delay allows the damper to reach the appropriate position to avoid unnecessary fan overload.

Minimum Position Control

There is a minimum damper position potentiometer on the EconoMi$er IV controller. (See Fig. 45.) The minimum damper position maintains the minimum airflow into the building during the occupied period.

When using demand ventilation, the minimum damper position represents the minimum ventilation position for VOC (volatile organic compound) ventilation requirements. The maximum demand ventilation position is used for fully occupied ventilation.

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 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 100OA ) + (TR x 100RA ) =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, and return-air temperature is 75_F.

(60 x .10) + (75 x .90) = 73.5_F

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. 41 and that the minimum position potentiometer is turned fully clockwise.

4.Connect 24 vac across terminals TR and TR1.

580J

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