AIR QUALITY SENSOR Ð Air quality (AQ) sensors are CO2 sensors shipped inside the fan section for ®eld instal- lation. To wire the sensors after they are mounted in the con- ditioned air space and return air duct, see Fig. 62 and the instructions shipped with the sensors. For each sensor, use two 2-conductor 20 AWG twisted-pair cables (unshielded) to connect the separate 24 vac power source to the sensor and the sensor to the option module (PSIO slave) terminals. To connect each AQ sensor to the option module, identify the positive (1) and negative (−) terminals on the sensor; connect AQ1 to terminals 25 and 26 and connect AQ2 to terminals 28 and 29.

OUTSIDE AIR VELOCITY PRESSURE (OAVP) SEN- SOR Ð The OAVP sensor is factory installed and wired. As shown in Fig. 62, the sensor's power wiring is connected to TB2, 9 and 10 for 39L units or TB2, 29 and 30 for 39NX units; the signal leads are connected to terminals 31 and 32 in the option module.

Note that if the velocity pressure of the supply and/or re- turn air is below 0.75 in. wg, the system may require trans- ducers with lower ranges than those of the default factory- supplied transducers. As a general rule, size transducers so that the maximum air velocity pressure is 75% of the transducer's maximum value. For example, if the 39L or 39NX unit produces a maximum air velocity pressure of

0.15in. wg, a transducer with a maximum value of

0.20in. wg can be used. Sizing the transducers according to these guidelines ensures that they have good resolution.

Factory-Supplied Return Fans with Inlet Guide Vanes (IGVs) are factory wired except for the air supply control signal from the air¯ow monitoring stations, which is con- nected in the ®eld to the bulkhead ®tting.

Return Fans with Field-Supplied IGV Actuators must be able to receive a 4 to 20 mA signal and may NOT have an im- pedance of more than 600 ohms. An isolated power source must be ®eld-supplied and installed. See Table 9 for recommended actuators.

To install actuators, see Fig. 65. Using a 2-conductor

20 AWG conductor cable (one twisted pair, unshielded) rated for the application, connect the positive (1) wire to terminal 37 in the option module. Connect the negative (−) wire to terminal 38. Connect the 24 vac power leads to TB2, terminals 23 and 24.

Field-Supplied Return Fans with Variable Frequency Drives must have 4 to 20 mA signal input boards and their own ®eld-supplied and installed power sources.

To install return fans with variable frequency drives, see Fig. 66. Using a 2-conductor 20 AWG conductor cable (one twisted pair, unshielded) rated for the application, con- nect the positive (1) signal wire to terminal 37 in the option module. Connect the negative signal (−) wire to terminal 38.

The supply fan minimum set point must be equal to the return fan minimum air¯ow, plus the delta air¯ow that is to be maintained.

LEGEND

AQ Ð Air Quality Sensor

OAVP Ð Outside Air Velocity Pressure Sensor

Field Wiring Factory Wiring

NOTE: See unit label diagram or Fig. 12 for remote-mount control box connections.

Fig. 62 Ð Air Quality and OAVP Sensor Wiring

FAN VOLUME CONTROL (Fig. 63)

Air¯ow Monitoring Stations are ®eld-selected and ®eld- installed in the supply and return air ducts; see Fig. 63. Install each monitoring station in a straight portion of the duct with any upstream or downstream elbows or ®ttings at least 2.5 diameters away.

Use approved plenum tubing to connect each monitoring station to the bulkhead ®ttings on top of the control box. For runs up to 50 ft, use 1¤4-in. OD tubing. For runs over 50 ft, use 3¤8-in. OD tubing.

Differential Pressure Transducers for fan volume control are factory-installed in the control box (two are supplied). The power supply for the transducers is also factory installed. Both transducers have pressure ranges of 0.0 to 1.0 in. wg and produce 2 to 10 vdc signals. See Fig. 64 for wiring details.

IGV Ð Inlet Guide Vane

Field Wiring

NOTE: Air monitoring stations are ®eld supplied and installed; pres- sure transducers are factory supplied and installed.

Fig. 63 Ð Field-Installed Fan Volume Control

62

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Carrier 39L specifications Air Quality and Oavp Sensor Wiring
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39L specifications

The Carrier 39L is a cutting-edge air conditioning unit designed for both residential and commercial applications, providing exceptional cooling and heating performance. Equipped with advanced technologies, this system ensures optimal climate control while maintaining energy efficiency.

One of the standout features of the Carrier 39L is its inverter technology. This innovation allows the system to adjust its compressor speed based on the ambient temperature, which results in a significant reduction in energy consumption. By operating at varying capacities rather than a fixed output, the 39L can maintain a consistent temperature, enhancing comfort while lowering electricity bills.

The Carrier 39L also includes a high-efficiency air filtration system, designed to capture dust, allergens, and other airborne particles. This not only improves indoor air quality but also promotes a healthier living environment. The filtration system is complemented by anti-bacterial treatment, ensuring that the air circulated within your space is both clean and refreshing.

In terms of design, the Carrier 39L boasts a sleek and compact form factor, making it easy to integrate into various settings, from homes to offices. Its quiet operation is another notable feature, as it minimizes noise levels, allowing occupants to enjoy a serene atmosphere without disruptive sound.

Further enhancing convenience, the Carrier 39L comes equipped with smart connectivity options. Users can control the unit remotely via a smartphone app, making it easy to adjust settings, program schedules, and monitor energy usage from anywhere. This feature not only improves user experience but also supports energy-saving practices.

Durability is also a key characteristic of the Carrier 39L. Constructed with high-quality materials and coated with corrosion-resistant treatments, the unit is built to withstand various environmental conditions. This ensures long-lasting performance and reduces the need for frequent maintenance.

Overall, the Carrier 39L is a versatile, efficient, and user-friendly air conditioning solution. Its blend of advanced technologies, energy-saving capabilities, and robust design makes it an ideal choice for those seeking reliable climate control in their spaces. Whether for residential comfort or commercial necessity, the Carrier 39L stands out as a leader in modern air conditioning.
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