Bryant 581B Supply Air Sensor Temperature/Resistance Values, EconoMi$er IV Control Modes

Table 3 — 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

G. EconoMi$er IV Control Modes

Determine the EconoMi$er IV control mode before set up of the control. Some modes of operation may require different sensors. Refer to Table 4. The EconoMi$er IV is supplied from the fac- tory 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.

Outdoor Dry Bulb Changeover

The standard controller is shipped from the factory config- ured for outdoor dry bulb changeover control. The outdoor air and supply air temperature sensors are included as stan- dard. For this control mode, the outdoor temperature is com- pared 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 outside air dampers to mini- mum position. If the outdoor-air temperature is below the set point, the position of the outdoor-air dampers will be con- trolled to provide free cooling using outdoor air. When in this mode, the LED next to the free cooling set point potentiome- ter will be on. The changeover temperature set point is con- trolled 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.

Differential Dry Bulb Control

For differential dry bulb control the standard outdoor dry bulb sensor is used in conjunction with an additional acces- sory dry bulb sensor (part number CRTEMPSN002A00). The accessory sensor must be mounted in the return airstream. See Fig. 34. Wiring is provided in the EconoMi$er IV wiring harness. See Fig. 27.

In this mode of operation, the outdoor-air temperature is compared to the return-air temperature and the lower tem- perature airstream is used for cooling. When using this mode of changeover control, turn the enthalpy set point potentiom- eter fully clockwise to the D setting. See Fig. 32.

Table 4 — 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
	and					CRCBDIOX005A00††
Duct-Mounted
	33ZCASPCO2**
CO2 Sensor

*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.

†33ZCSENCO2 is an accessory CO2 sensor.

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

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

Fig. 32 — EconoMi$er IV Controller Potentiometer

and LED Locations

19

	18	LED ON
				D
	17
	16		LED OFF		LED ON
						C
	15
mA	14				LED OFF			LED ON
									B
	13
	12							LED OFF		LED ON
												A
	11
	10										LED OFF
	9												100
	40	45	50	55	60	65	70	75	80	85	90	95
					DEGREES FAHRENHEIT

Fig. 33 — Outdoor Air Temperature

Changeover Set Points

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