Heat Interlock Relay (Fig. 27) Ð The heat interlock relay (HIR) is factory wired and installed on VAV units only. It is a single-pole,double-throw (SPDT) relay that provides normally-open and normally-closed contacts to interface with air terminal units. It allows the air terminals to open when the PIC unit goes into the heating mode. The contacts are silver cadmium oxide and are rated as follows:

48 va at 24 vac and .25 power factor

125 va at 115 vac and .25 power factor

125 va at 230 vac and .25 power factor

The contact terminations are no. 6 screw terminals.

NOTE: The HIR is not used in digital air volume control (DAV) applications.

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Fig. 27 Ð Relay (P/N HK35AB001)

Fan Relay Ð The fan relay is factory wired and installed on all 39L and 39NX units. It is a SPST relay that provides a normally-open contact. The relay interfaces with the mo- tor starter circuit and automatically starts/stops the fan when the HOA switch is in the AUTO mode. The contacts are sil- ver cadmium oxide and are rated as follows:

48 va at 24 vac and .25 power factor

125 va at 115 vac and .25 power factor

125 va at 230 vac and .25 power factor

The contact terminations are factory wired to TB1.

Duct High Humidity Switch (Fig. 28) Ð The duct high humidity switch (DHH) is shipped inside the fan sec- tion. It is used as a safety input when the humidity control options have been ordered. The DHH adjustment knob pro- vides settings from 15 to 95% humidity.

Locate the DHH control element in the duct, downstream of the humidi®er. Adjust the DHH to the ASHRAE (American Society of Heating, Refrigeration, and Air Con- ditioning Engineers) recommended maximum setting of 80%. Settings higher than 80% are not recommended.

The DHH is normally mounted in a horizontal position on the outside surface of the duct with the sensing element ex- posed to freely circulating air.

DO NOT install the duct high humidity switch in lo- cations where excessive moisture, corrosive fumes, and/or vibration are present. Be sure to allow minimum dimen- sions from the elbows or junctions as indicated in Fig. 29.

Mount the DHH as follows:

1.Position the mounting template on the duct. Remove ad- hesive backing and press template onto duct.

2.Drill four 1¤8-in. mounting holes as indicated on the template.

3.Cut out center portion of duct as outlined on template.

4.Mount DHH to duct using screws provided.

For distances up to 500 ft, use 2-conductor 20 AWG cable to connect the switch to the PIC control box terminals. Refer to Field Wiring Connections section, page 52 for fur- ther details.

The DHH adjustment knob provides settings from 15 to 95% relative humidity, The scale range is marked on the face of the switch. The high humidity set point should be at least 65%.

NOTE: The duct high humidity switch has a relative humid- ity differential of 5%.

Fig. 28 Ð Duct High Humidity Switch

(P/N HL38ZG024)

Fig. 29 Ð Duct High Humidity Switch

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Carrier 39L specifications COI L Comno

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.