Bryant 580F operation manual EconoMi$erIV Controller, CO2 Sensor Maximum Range Setting

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
SO+		Set	3	4
SO	2V	10V
SR+	Free		EF	EF1
	Cool
SR	B	C
	A	D

Fig. 32 — EconoMi$erIV Controller

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

Fig. 33 — CO2 Sensor Maximum Range Setting

To determine the minimum position setting, perform the following procedure:

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

(TO x	OA	) + (TR x	RA	) = TM
	100		100

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 posi- tioning is being used, make sure that the terminals are wired according to Fig. 27 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 EconoMi$erIV damper is desirable when requiring additional temporary ventilation. If a field-supplied remote potentiometer (Honeywell part number S963B1128) is wired to the EconoMi$erIV 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 EconoMi$erIV controller. Wire the field-supplied potenti- ometer to the P and P1 terminals on the EconoMi$erIV con- troller. See Fig. 30.

Damper Movement

Damper movement from full open to full closed (or vice versa) takes 21/2 minutes.

Thermostats

The EconoMi$erIV control works with conventional thermo- stats that have a Y1 (cool stage 1), Y2 (cool stage 2), W1 (heat stage 1), W2 (heat stage 2), and G (fan). The EconoMi$erIV control does not support space temperature sensors. Connections are made at the thermostat terminal connection board located in the main control box.

Occupancy Control

The factory default configuration for the EconoMi$erIV con- trol is occupied mode. Occupied status is provided by the red jumper from terminal TB2-9 to terminal TB2-10. When unoccupied mode is desired, install a field-supplied timeclock function in place of the jumper between terminals TB2-9 and TB2-10. See Fig. 27. When the timeclock contacts are closed, the EconoMi$erIV control will be in occupied mode. When the timeclock contacts are open (removing the 24-v signal from terminal N), the EconoMi$erIV will be in unoccupied mode.

Demand Controlled Ventilation (DCV)

When using the EconoMi$erIV for demand controlled venti- lation, there are some equipment selection criteria which should be considered. When selecting the heat capacity and cool capacity of the equipment, the maximum ventilation rate must be evaluated for design conditions. The maximum damper position must be calculated to provide the desired fresh air.

Typically the maximum ventilation rate will be about 5 to 10% more than the typical cfm required per person, using normal outside air design criteria.

A proportional anticipatory strategy should be taken with the following conditions: a zone with a large area, varied occupancy, and equipment that cannot exceed the required ventilation rate at design conditions. Exceeding the required ventilation rate means the equipment can condition air at a maximum ventilation rate that is greater than the required ventilation rate for maximum occupancy. A proportional- anticipatory strategy will cause the fresh air supplied to increase as the room CO2 level increases even though the CO2 set point has not been reached. By the time the CO2 level reaches the set point, the damper will be at maximum ventilation and should maintain the set point.

In order to have the CO2 sensor control the economizer damper in this manner, first determine the damper voltage output for minimum or base ventilation. Base ventilation is the ventila- tion required to remove contaminants during unoccupied periods. The following equation may be used to determine the

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