Carrier 50TCA04-A07 appendix Enthalpy Changeover Setpoints, Indoor Air Quality IAQ Sensor Input

50TC

																													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)

C06037

Fig. 62 - Enthalpy Changeover Setpoints

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. 63 - EonoMi$er IV Control

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 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. 52.) Mount the return air enthalpy sensor in the return air duct. (See Fig. 61.) Wiring is provided in the EconoMi$er IV wiring harness. (See Fig. 52.) The outdoor enthalpy changeover setpoint is set with the outdoor enthalpy setpoint potentiometer on the EconoMi$er IV controller. When using this mode of changeover control, turn the enthalpy setpoint potentiometer fully clockwise to the D setting.

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. 64.)

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