Bryant 580J*04--12 Differential Enthalpy Control, Mounting Location, Outdoor Enthalpy Changeover

provided in the EconoMi$er IV wiring harness. (See Fig. 38.)

outdoor dry bulb temperature sensor with the accessory enthalpy sensor in the same mounting location. (See Fig. 39.) When the outdoor air enthalpy rises above the

580J

ECONOMI$ERIV

ECONOMI$ERIV

CONTROLLER

GROMMET

RETURN AIR

SENSOR

RETURN DUCT (FIELD-PROVIDED)

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outdoor enthalpy changeover setpoint, the outdoor-air damper moves to its minimum position. The outdoor enthalpy changeover setpoint is set with the outdoor enthalpy setpoint potentiometer on the EconoMi$er IV controller. The setpoints are A, B, C, and D. (See Fig. 46.) The factory-installed 620-ohm jumper must be in place across terminals SR and SR+ on the EconoMi$er IV controller.

Differential Enthalpy Control

For differential enthalpy control, the EconoMi$er IV controller uses two enthalpy sensors (HH57AC078 and CRENTDIF004A00), one in the outside air and one in the return air duct. The EconoMi$er IV controller compares the outdoor air enthalpy to the return air enthalpy to determine EconoMi$er IV use. The controller selects the lower enthalpy air (return or outdoor) for cooling. For example, when the outdoor air has a lower enthalpy than the return air, the EconoMi$er IV opens to bring in

Fig. 48 - Return Air Temperature or Enthalpy Sensor

Mounting Location

In this mode of operation, the outdoor-air temperature is compared to the return-air temperature and the lower temperature airstream is used for cooling. When using this mode of changeover control, turn the enthalpy setpoint potentiometer fully clockwise to the D setting. (See Fig. 45.)

Outdoor Enthalpy Changeover

For enthalpy control, accessory enthalpy sensor (part number HH57AC078) is required. Replace the standard

outdoor air for free cooling.

Replace the standard outside air dry bulb temperature sensor with the accessory enthalpy sensor in the same mounting location. (See Fig. 39.) Mount the return air enthalpy sensor in the return air duct. (See Fig. 48.) Wiring is provided in the EconoMi$er IV wiring harness. (See Fig. 41.) The outdoor enthalpy changeover setpoint is set with the outdoor enthalpy setpoint potentiometer on the EconoMi$er IV controller. When using this mode of changeover control, turn the enthalpy setpoint potentiometer fully clockwise to the D setting.

																													85		90	95	100		105	110
																													(29)		(32)	(35)	(38)		(41)	(43)
																											46
CONTROL			CONTROL POINT																					4	4
CURVE APPROX. deg. F (deg. C)
																				42								80
				AT 50% RH
A				73 (23)													AIR											(27)
																			40
B				70 (21)												DRY																		(%)
C				67 (19)									POUND				3	8														HUMIDITY
D				63 (17)
															36												75
												PER														(24)
													3	4
									BTU																						RELATIVE
												32
																							70
										30
																					(21)
								28
																						0
						ENTHALPY														1	0			0
							26												65				9			80
					2	4													(18)								70
																												0
				2	2											60												6
																												50
			2	0												(16)
																		A											4	0
		8											55
	1
													(13)			B															30
1	6
												50
14														C
											(10)																						20
12								45				D
							40	(7)
																																				0
							(4)
																																				1
					35
					(2)
																											D C	B	A
																																				HIGH LIMIT
																																				CURVE
					35		40	45				50		55		60			65				70				75	80	85		90	95	100		105	110
					(2)		(4)	(7)				(10)	(13)			(16)			(18)				(21)				(24)	(27)	(29)		(32)	(35)	(38)		(41)	(43)
					APPROXIMATE DRY BULB TEMPERATURE--degrees F (degrees C)

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Fig. 49 - Enthalpy Changeover Setpoints

38