Carrier 48HJ004---007 Dehumidification of Fresh Air with DCV Control, Adjust Evaporator-Fan Speed

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. 46 ---EconoMi$er IV Control

CO2 SENSOR MAX RANGE SETTING

	6000
(ppm)	5000
CONFIGURATION	4000						800 ppm
	3000						900 ppm
							1000 ppm
	2000						1100 ppm
RANGE	1000
	0
	2	3	4	5	6	7	8
	DAMPER VOLTAGE FOR MAX VENTILATION RATE

C06039

Fig. 47 ---CO2 Sensor Maximum Range Setting

CO2 Sensor Configuration

The CO2 sensor has preset standard voltage settings that can be selected anytime after the sensor is powered up. (See Table 8.)

Use setting 1 or 2 for Carrier equipment. (See Table 8.)

1.Press Clear and Mode buttons. Hold at least 5 seconds until the sensor enters the Edit mode.

2.Press Mode twice. The STDSET Menu will appear.

3.Use the Up/Down button to select the preset number. (See Table 8.)

4.Press Enter to lock in the selection.

5.Press Mode to exit and resume normal operation.

The custom settings of the CO2 sensor can be changed anytime after the sensor is energized. Follow the steps below to change the non-standard settings:

1.Press Clear and Mode buttons. Hold at least 5 seconds until the sensor enters the Edit mode.

2.Press Mode twice. The STDSET Menu will appear.

3.Use the Up/Down button to toggle to the NONSTD menu and press Enter.

4.Use the Up/Down button to toggle through each of the nine variables, starting with Altitude, until the desired setting is reached.

5.Press Mode to move through the variables.

6.Press Enter to lock in the selection, then press Mode to continue to the next variable.

Dehumidification of Fresh Air with DCV Control

Information from ASHRAE indicates that the largest humidity load on any zone is the fresh air introduced. For some applications, a device such as a 62AQ energy recovery unit is added to reduce the moisture content of the fresh air being brought into the building when the enthalpy is high. In most cases, the normal heating and cooling processes are more than adequate to remove the humidity loads for most commercial applications.

If normal rooftop heating and cooling operation is not adequate for the outdoor humidity level, an energy recovery unit and/or a dehumidification option should be considered.

Step 9 —Adjust Evaporator-Fan Speed

Adjust evaporator-fan speed to meet jobsite conditions.

Tables 9 and 10 show fan rpm at motor pulley settings. Tables 11 and 15 show maximum amp draw of belt-drive motor. Table 14 shows sound data. Refer to Tables 16-35 for performance data. See Table 36 for accessory static pressure drop. See Fig. 48 for the Humidi-MiZer™system static pressure drops.

Belt drive motors

Fan motor pulleys are factory set for speed shown in Table 1 or 2. Check pulley alignment and belt tension prior to start-up.

To change fan speed:

1.Shut off the unit power supply and tag disconnect.

2.Loosen the belt by loosening the fan motor mounting nuts. (See Fig. 49.)

3.Loosen movable pulley flange setscrew. (See Fig. 50.)

4.Screw movable flange toward fixed flange to increase speed and away from fixed flange to decrease speed. Increasing fan speed increases load on motor. Do not exceed maximum speed specified in Table 1 or 2.

5.Set movable flange at nearest keyway of pulley hub and tighten setscrew. (See Table 1 or 2 for speed change for each full turn of pulley flange.)

6.Adjust belt tension and align gan and motor pulleys per guidance below.

To align fan and motor pulleys, loosen fan pulley setscrews and slide fan pulley along fan shaft. Make angular alignment by loosening motor from mounting.

Additional motor and fan alignment, as well as angular alignment can be made by loosening the four motor mounting bolts from the mounting plate.

To adjust belt tension:

1.Loosen the two motor mounting nuts as shown in Fig. 49. Some models may have a third mounting nut located on the opposite side of the fan motor mounting plate.

2.Slide motor mounting plate away from fan scroll for proper belt tension (1/2-in. deflection with 8 to 10 lb of force) and tighten mounting nuts.

3.Adjust lock bolt and nut on mounting plate to secure motor in fixed position.

48HE,HJ

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