INDOOR-AIR QUALITY (IAQ) Ð This function main- tains the correct occupied ventilation rate using CO2 as an indicator of occupancy level or controls the levels of volatile organic compounds (VOCs) or other indoor air pollutants by modulating the mixed air dampers. Varying quantities of out- door air are admitted during the Occupied period to main- tain the ventilation rate at its set point or pollutants at or below the con®gured set points of the air-quality (AQ) sen- sors. See Fig. 76.

CO2 sensors are available from the factory as options for ®eld installation. VOC or other types of sensors can be ®eld- supplied and installed. Sensors used with the IAQ feature can be con®gured several different ways:

·One sensor can be installed in either the space or return air stream to continuously monitor a single gas.

·Two sensors (monitoring the same gas) can be installed in different locations to provide separate inputs. For ex- ample, one sensor can be located in an occupied space and another in the return air duct, or each sensor can be in- stalled in a different occupied space.

·Two sensors (typically VOC sensors monitoring the same gas) can be installed inside and outside the occupied space for comparative measurements. The control is con®gured to modify the damper position based on the value of the sensor in the occupied space, but before admitting outside air, the control performs a differential check to determine if the value of the sensor measuring the outside air is higher. If the outside sensor has a higher value, the damper does not change position.

Systems with One AQ Sensor Ð During the unoccupied period, the minimum damper position maintained by the IAQ control is 0. During the occupied period, the control

reads the AQ1 sensor input and compares it to the con®g- ured set point. The control then calculates the minimum damper position to maintain the set point. If no other control is at- tempting to adjust the dampers to a more fully open position than the IAQ control, the damper is adjusted to the position determined by the IAQ control. Otherwise, the damper is positioned by the superseding control routine or at its con- ®gured minimum position.

Systems with Two AQ Sensors (Separate Readings) Ð The preceding sequence for the AQ1 sensor also applies to the AQ2 sensor, but the damper position is determined by either the AQ1 or the AQ2 sensor according to which sensor value demands the more fully open damper position.

Systems with Two AQ Sensors (Differential Check) Ð If dif- ferential sensing is con®gured for two VOC sensors, the con- trol reads the AQ2 (outside air) sensor to determine if its value is greater or less than that of the AQ1 (indoor air) sen- sor. If the AQ2 value is greater than the value of the AQ1 sensor, the mixed-air damper position is set to 0. If the AQ2 value is less than the AQ1 value (by at least 1% of the con- ®gured minimum sensor value), the control uses the AQ1 value to modulate the dampers and maintain the AQ set point.

IAQ System Protection Ð To protect the system against coil freeze-up in cold climates or high heat and humidity in warm climates, the system provides several user-selectable fea- tures to override or modify the IAQ functions. An adjustable maximum position for the mixed-air damper is provided for each AQ sensor, and a selection is available to maintain the minimum mixed-air temperature at approximately 45 F. Space temperature and humidity protection can temporarily sus- pend IAQ functions until the temperature and humidity con- ditions return to the desired set points. On VAV systems dur- ing cooling, the IAQ function can be limited to maintain the required supply-air temperature.

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Carrier 39L specifications

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.