Bryant 607C-A installation instructions Operation, CO2 Sensor Standard Settings

Table 16 – CO2 Sensor Standard Settings

			VENTILATION		CO2	OPTIONAL	RELAY
SETTING	EQUIPMENT	OUTPUT	RATE	ANALOG	CONTROL	RELAY	HYSTERESIS
			(CFM/	OUTPUT	RANGE	SETPOINT
							(PPM)
			PERSON)		(PPM)	(PPM)
1		Proportional	Any	0---10V	0---2000	1000	50
				4---20mA
2	Interface w/Standard Building	Proportional	Any	2---10V	0---2000	1000	50
	Control System			7---20mA
3		Exponential	Any	0---10V	0---2000	1100	50
				4---20mA
4		Proportional	15	0---10V	0---1100	1100	50
				4---20mA
5	Economizer	Proportional	20	0---10V	0---900	900	50
				4---20mA
6		Exponential	15	0---10V	1---1100	1100	50
				4---20mA
7		Exponential	20	0---10V	0---900	900	50
				4---20mA
8	Health & Safety	Proportional	---	0---10V	0---9999	5000	500
				4---20mA
9	Parking/Air Intakes/Loading Docks	Proportional	---	0---10V	0---2000	700	50
				4---20mA

Table 17 – CO2 Sensor Standard Settings Economizer Input/Output Logic

	INPUTS						OUTPUTS
DEMAND	ENTHALPY				COMPRESSOR		N TERMINAL
CONTROL
			Y1	Y2	STAGE	STAGE	OCCUPIED	UNOCCUPIED
VENTILATION	OUTDOOR	RETURN
(DCV)					1	2	DAMPER
	High (Free Cooling		On	On	On	On
		Low	On	Off	On	Off	Minimum position	Closed
	LED off)
Below set (DCV			Off	Off	Off	Off
LED Off)
	Low (Free Cooling		On	On	On	Off	Modulating** (between min.	Modulating** (between closed
		High	On	Off	Off	Off	position and full ---open)	and full ---open)
	LED on)
			Off	Off	Off	Off	Minimum position	Closed
	High (Free Cooling		On	On	On	On	Modulating{{ (between	Modulating{{ (between closed
		Low	On	Off	On	Off	min. position and DCV
	LED off)							and DCV maximum)
							maximum)
Above set (DCV			Off	Off	Off	Off
LED On)
	Low (Free Cooling		On	On	On	Off
		High	On	Off	Off	Off	Modulating***	Modulating{{{
	LED on)
			Off	Off	Off	Off

* For single enthalpy control, the module compares outdoor enthalpy to the ABCD set point.

{Power at N terminal determines Occupied/Unoccupied setting: 24 vac (Occupied), now power (Unoccupied). **Modulating is based on the supply--- air sensor signal.

{{Modulation is based on the DCV signal.

***Modulation is based on the greater of DCV and supply--- air sensor signals, between minimum position and either maximum position (DCV) or fully open (supply--- air signal).

{{{Modulating is based on the greater of DCV and supply--- air sensor signals, between closed and wither maximum position (DCV) or fully open (supply--- air signal).

607C-- -- A

OPERATION

Sequence of Operation—When free cooling is not available, the compressor will be controlled by the thermostat. When free cooling is available, the outdoor-air damper is modulated by the Economizer control to provide a 50_ to 55_F (10_ to 12.8_C) supply-air temperature into the zone. As the supply-air temperature fluctuates above 55_ (12.8_C) or below 50_F (10_C), the dampers will be modulated (open or close) to bring the supply-air temperature back within the set points. For Economizer operation, there must be a thermostat call for the fan (G). This will move the damper to its minimum position during the occupied mode.

NOTE: The DCV Max potentiometer must be closed (CCW) when not using CO2 sensor.

Above 50_F (10_C) supply-air temperature, the dampers will modulate from 100% open to the minimum open position. From 50_F to 45_F (10_ to 7.2_C) supply-air temperature, the dampers will maintain at the minimum open position. Below 45_F (7.2_C), the dampers will be completely shut. As the supply-air temperature rises, the dampers will come back open to the minimum open position once the supply-air temperature rises to 48_F (8.9_C). If

power exhaust is installed, as the outdoor-air damper opens and closes, the power exhaust fans will be energized and deenergized. If field-installed accessory CO2 sensors are connected to the Economizer control, a demand controlled ventilation strategy will begin to operate. As the CO2 level in the zone increases above the CO2 set point, the minimum position of the damper will be increased proportionally. As the CO2 level decreases because of the increase in fresh air, the outdoor-air damper will be proportionally closed. Damper position will follow the higher demand condition from DCV mode or free cooling mode. Damper movement from full closed to full open (or vice versa) will take between 1 1/2 and 2 1/2 minutes. If free cooling can be used as determined from the appropriate changeover command (dry bulb, enthalpy curve, or differential enthalpy), a call for cooling (Y1 closes at the thermostat) will cause the control to modulate the dampers open to maintain the supply air temperature set point at 50_ to 55_F (10_ to 12.8_C). As the supply air temperature drops below the set point range of 50_ to 55_F (10_ to 12.8_C), the control will modulate the outdoor-air dampers closed to maintain the proper supply-air temperature.

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