Bryant 551B,C, EconoMi$er IV Control Modes, Outdoor Dry Bulb Changeover, EconoMi$er IV Wiring

551B,C

EconoMi$er IV Control Modes							Outdoor Dry Bulb Changeover
Determine the EconoMi$er IV control mode before set up of the							The standard controller is shipped from the factory configured for
control. Some modes of operation may require different							outdoor dry bulb changeover control. The outdoor-air and
sensors. (See Table 6.) The EconoMi$er IV is supplied from the							supply-air temperature sensors are included as standard. For this
factory with a supply-air temperature sensor and an outdoor- air							control mode, the outdoor temperature is compared to an
temperature sensor. This allows for operation of the EconoMi$er							adjustable set point selected on the control. If the outdoor-air
IV with outdoor air dry bulb changeover control. Additional							temperature is above the set point, the EconoMi$er IV will adjust
accessories can be added to allow for different types of							the outdoor-air dampers to minimum position. If the outdoor air
changeover control and operation of the EconoMi$er IV and unit.							temperature is below the set point, the position of the outdoor air
							dampers will be controlled to provide free cooling using outdoor
Table 6—EconoMi$er IV Sensor Usage							air. When in this mode, the LED next to the free cooling set point
							potentiometer will be on. The changeover temperature set point is
							controlled by the free cooling set point potentiometer located on
	ECONOMI$ER IV WITH OUTDOOR AIR
							the control. (See Fig. 33.) The scale on the potentiometer is A, B,
APPLICATION		DRY BULB SENSOR
		Accessories Required					C, and D. See Fig. 34 for the corresponding temperature
Outdoor Air	None. The outdoor air dry bulb sensor						changeover values.
Dry Bulb		is factory installed.					Differential Dry Bulb Control
Differential		CRTEMPSN002A00*
Dry Bulb							For differential dry bulb control the standard outdoor dry bulb
Single Enthalpy			HH57AC078				sensor is used in conjunction with an additional accessory dry
			HH57AC078
Differential							bulb sensor (part number CRTEMPSN002A00). The accessory
					and
Enthalpy							sensor must be mounted in the return airstream. (See Fig. 35.)
		CRENTDIF004A00*
							Wiring is provided in the EconoMi$er IV wiring harness. (See
CO2 for DCV
							Fig. 27.)
Control using a		33ZCSENCO2
Wall-Mounted							In this mode of operation, the outdoor-air temperature is
CO2 Sensor
							compared to the return-air temperature and the lower temperature
CO2 for DCV	33ZCSENCO2†			O
Control using a	and					CRCBDIOX005A00††	airstream is used for cooling. When using this mode of
Duct-Mounted	33ZCASPCO2**			R			changeover control, turn the enthalpy setpoint potentiometer fully
CO2 Sensor
							clockwise to the D setting. (See Fig. 33.)

*CRENTDIF004A00 and CRTEMPSN002A00 accessories are used on many different base units. As such, these kits may contain parts that will not be needed for installation.

2sensor.

**33ZCASPCO2 is an accessory aspirator box required for duct-mounted applications.† 33ZCSENCO2 is an accessory CO

††CRCBDIOX005A00 is an accessory that contains both 33ZCSENCO2 and 33ZCASPCO2 accessories.

FOR OCCUPANCY CONTROL

REPLACE JUMPER WITH

FIELD-SUPPLIED TIME CLOCK

8

7

LEGEND	Potentiometer Defaults Settings:
DCV— Demand Controlled Ventilation	Power Exhaust	Middle
	Minimum Pos.	Fully Closed
IAQ — Indoor Air Quality
	DCV Max.	Middle
LA — Low Ambient Lockout Device
	DCV Set	Middle
OAT — Outdoor-Air Temperature
	Enthalpy	C Setting
POT — Potentiometer

RAT — Return-Air Temperature

NOTES:

1.620 ohm, 1 watt 5% resistor should be removed only when using differential enthalpy or dry bulb.

2.If a separate field-supplied 24 v transformer is used for the IAQ sensor power supply, it cannot have the secondary of the transformer grounded.

3.For field-installed remote minimum position POT, remove black wire jumper between P and P1 and set control minimum position POT to the minimum position.

C06028

Fig. 27 ---EconoMi$er IV Wiring

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