SPACE TEMPERATURE RESET Ð The space tempera- ture reset is used to reset the supply-air temperature set point upward as the space temperature falls below the Occupied Cooling set point. As space temperature falls below the cool- ing set point, the space temperature is reset upward as a func- tion of the reset ratio. The reset ratio is the degrees of change in supply-air temperature per degree of space temperature change. A reset limit speci®es the maximum number of de- grees the supply-air temperature may be raised. Both the re- set ratio and the reset limits are user adjustable.

When the fan is ON, and the system is in the Occupied mode, the control reads the space temperature sensor and computes the reset value. If the reset value is greater than the reset limit, the control uses the reset limit as the reset value. The modi®ed supply air temperature set point is de- termined by adding the reset value to the con®gured supply air temperature set point. This value is then used by the cool- ing coil algorithm.

TWO-STEP DEMAND LIMITING (Available on Units Connected to the Carrier Comfort Network Only) Ð If the Demand Limit option is enabled, the control receives and accepts redline alerts and loadshed commands from the Net- work Loadshed option. See the CCN Loadshed manual for additional information.

When a redline alert is received, the system limits the maxi- mum volume (percent of fully open IGVs) per the user- de®ned demand limit no. 1 set point.

When a loadshed command is received, the maximum vol- ume is limited per the user-de®ned demand limit no. 2 set point.

The maximum loadshed timer prevents the system from remaining in Loadshed, if the control loses communications with the Loadshed option. If the timer expires before the

loadshed command is cleared by the Loadshed option, the control clears the loadshed command itself and returns to normal control. The loadshed timer is factory set at 60 minutes.

MIXED-AIR DAMPER CONTROL Ð The mixed-air damper control modulates the outside-air, return-air, and exhaust-air dampers. When outside-air conditions are unsuitable for at- mospheric cooling, the dampers are held at the minimum ad- justable outside-air position. The mixed-air dampers are modulated to maintain a mixed-air temperature equal to supply- air temperature set point minus 3° F. The dampers can also be modulated to maintain a user-con®gured mixed-air tem- perature set point.

If the supply fan is OFF, the mixed-air dampers are held closed to outside air and held open to return air. If the supply fan is ON, and the system is not in the HEAT mode, the system determines if outside-air conditions are suitable for atmospheric cooling. The outside-air temperature is com- pared to the space temperature. If the outside-air tempera- ture is less than the space temperature, the system performs either an enthalpy check using an outside-air enthalpy switch or a differential enthalpy check.

If the outside conditions are suitable, the control uses the mixed-air sensor to maintain the discharge temperature (when- ever the mixed-air sensor option is installed). If the sensor is not provided or fails, the control uses the supply-air sen- sor to modulate the dampers and achieve the set point.

When the outside temperature is less than 40 F, the mixed- air damper opening rate is limited to 5% per minute to pro- tect against nuisance low temperature thermostat tripping and coil freeze-up. Rate limiting is off when the dampers are closed.

102

Page 102
Image 102
Carrier 39L specifications 102

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.