Carrier 39L specifications

Fig. 39 Ð Air Quality (CO2) Sensor

(Wall Mount Version Shown)

SPAN

								9A32201
			CORPORATION
	ZERO							-012
							-04
						-001C
CARRIER					T40			water
					1
				:
	TRANSDUCER				0	.	of
				:
						in
PRESSURE	Number-				.
	Part	:		0
	Range			OUT		+
				-
IN	.
	Vac
24

PRESSURE

LO

HI

CO2 CONCENTRATION (PPM)

Fig. 40 Ð Ventilation Rates Based on CO2 Set Point

Constant Outside Air (OAC) Control Ð This fea- ture ensures a continuous supply of outside air to the unit and occupied space. The OAC control monitors the outside air velocity pressure (OAVP) with a probe and pressure trans- ducer. The pressure transducer is factory-installed; the probe is factory-supplied for ®eld installation in the outside air ducts. See Fig. 41 and 42.

PROBE INSTALLATION Ð Locate each probe in a straight portion of the outside air duct with any dampers, elbows, or ®ttings at least 2 diameters away. The probe should be in a portion of the duct where the air¯ow is uniform, so that the probe senses the average air velocity in the duct. The probe must also be located so that measurements at the probe are not in¯uenced by the opening or closing of the outdoor-air dampers.

Install the probe at a 90 degree angle to the air¯ow and ensure that the holes in the probe are facing and in line with the air¯ow. The probe tube that is closest to the incoming air¯ow measures velocity pressure; the rear tube measures duct static pressure. Use approved plenum tubing to connect the probe to the bulkhead ®ttings on top of the control box. For runs up to 150 ft, use 1¤4-in. OD tubing. For runs over 150 ft, use 3¤8-in. OD tubing. Use at least 25 ft of tubing to prevent pulsations and erratic operation. Coil any extra tub- ing if necessary.

If the outside air duct is large, additional probes can be installed in the duct and manifolded to obtain a more accu- rate velocity pressure reading for the entire duct. Manifold tubing must be larger than the plenum tubing connecting the manifold to the control box. See Fig. 43 and the preceding for recommended tube sizes.

Fig. 41 Ð OAVP Transducer (P/N HK05ZG004)

Fig. 42 Ð OAVP Probe (P/N 35DN40007001)

NOTE: High-pressure manifold connections shown. Low-pressure con- nections are identical and must duplicate high-pressure connections.

Fig. 43 Ð Probe Manifolding

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