Carrier 50TFQ008-012 Supply Air Sensor Temperature, Resistance Values, EconoMi$er IV Sensor Usage

ECONOMI$ER IV STANDARD SENSORS

Outdoor Air Temperature (OAT) Sensor — The outdoor air temperature sensor (HH57AC074) is a 10 to 20 mA device used to measure the outdoor-air temperature. The outdoor-air temperature is used to determine when the EconoMi$er IV can be used for free cooling. The sensor is factory-installed on the EconoMi$er IV in the outdoor airstream. See Fig. 19. The op- erating range of temperature measurement is 40 to 100 F.

Supply Air Temperature (SAT) Sensor — The supply air temperature sensor is a 3 K thermistor located at the inlet of the indoor fan. See Fig. 31. This sensor is factory installed. The op- erating range of temperature measurement is 0° to 158 F. See Table 6 for sensor temperature/resistance values.

The temperature sensor looks like an eyelet terminal with wires running to it. The sensor is located in the “crimp end” and is sealed from moisture.

Table 6 — Supply Air Sensor Temperature/

Resistance Values

TEMPERATURE (F)	RESISTANCE (ohms)
–58	200,250
–40	100,680
–22	53,010
–4	29,091
14	16,590
32	9,795
50	5,970
68	3,747
77	3,000
86	2,416
104	1,597
122	1,080
140	746
158	525
176	376
185	321
194	274
212	203
230	153
248	116
257	102
266	89
284	70
302	55

Outdoor Air Lockout Sensor — The Economi$er IV is equipped with an ambient temperature lockout switch located in the outdoor air stream which is used to lockout the compres- sors below a 42 F ambient temperature. See Fig. 19.

ECONOMI$ER IV CONTROL MODES

IMPORTANT: The optional EconoMi$er2 does not include a controller. The EconoMi$er2 is operated by a 4 to 20 mA signal from an existing field-supplied controller (such as PremierLink™ control). See Fig. 27 for wiring information.

Determine the EconoMi$er IV control mode before set up of the control. Some modes of operation may require different sen- sors. Refer to Table 7. The EconoMi$er IV is supplied from the factory with a supply air temperature sensor and an outdoor air temperature sensor. This allows for operation of the EconoMi$er IV with outdoor air dry bulb changeover control. Additional accessories can be added to allow for different types of changeover control and operation of the EconoMi$er IV and unit.

Table 7 — EconoMi$er IV Sensor Usage

	ECONOMI$ER IV WITH OUTDOOR AIR
APPLICATION		DRY BULB SENSOR
		Accessories Required
Outdoor Air	None. The outdoor air dry bulb sensor
Dry Bulb		is factory installed.
Differential		CRTEMPSN002A00*
Dry Bulb
Single Enthalpy		HH57AC078
Differential		HH57AC078
				and
Enthalpy
		CRENTDIF004A00*
CO2 for DCV
Control using a		33ZCSENCO2
Wall-Mounted
CO2 Sensor
CO2 for DCV	33ZCSENCO2†
Control using a			OR		CRCBDIOX005A00††
	and
Duct-Mounted
	33ZCASPCO2**
CO2 Sensor

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

†33ZCSENCO2 is an accessory CO2 sensor.

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

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

Outdoor Dry Bulb Changeover — The standard controller is shipped from the factory configured for outdoor dry bulb changeover control. The outdoor air and supply air temperature sensors are included as standard. For this control mode, the outdoor temperature is compared to an adjustable set point selected on the control. If the outdoor-air temperature is above the set point, the EconoMi$er IV will adjust the outdoor air dampers to minimum position. If the outdoor-air temperature is below the set point, the position of the outdoor air dampers will be controlled to provide free cooling using outdoor air. When in this mode, the LED next to the free cooling set point potenti- ometer will be on. The changeover temperature set point is controlled by the free cooling set point potentiometer located on the control. See Fig. 32. The scale on the potentiometer is A, B, C, and D. See Fig. 33 for the corresponding temperature changeover values.

SUPPLY AIR

TEMPERATURE

SENSOR

MOUNTING

LOCATION

SUPPLY AIR

TEMPERATURE

SENSOR

Fig. 31 — Supply Air Sensor Location

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