If the 50HCQ unit has an economizer system and free-cooling operation is required, a sensor representing Return Air Temperature must also be connected (field-supplied and installed). This sensor may be a T-55 Space Sensor (see Fig. 31) installed in the space or in the return duct, or it may be sensor PNO 33ZCSENSAT, installed in the return duct. Connect this sensor to TB1-1 and TB1-3 per Fig. 32.

Configure the Unit for Thermostat Mode —

Connect to the CCN bus using a CCN service tool and navigate to PremierLink Configuration screen for Operating Mode. Default setting is Sensor Mode (value 1). Change the value to 0 to reconfigure the controller for Thermostat Mode.

Differential Enthalpy Control —

Differential enthalpy control is provided by sensing and comparing the outside air and return air enthalpy conditions. Install the outdoor air enthalpy control as described above. Add and install a return air enthalpy sensor.

Return Air Enthalpy Sensor —

Mount the return-air enthalpy sensor (33CSENTSEN) in the return-air section of the economizer. The return air sensor is wired to the enthalpy controller (33CSENTHSW). See Fig. 37.

50HCQA

When the PremierLink is configured for Thermostat Mode, these functions are not available: Fire Shutdown (FSD), Remote Occupied (RMTOCC), Compressor Safety (CMPSAFE), Supply Fan Status (SFS), and Filter Pressure Switch (FILTER).

Economizer Controls

Outdoor Air Enthalpy Control (PNO 33CSENTHSW) —

The enthalpy control (33CSENTHSW) is available as a field-installed accessory to be used with the EconoMi$er2

4-20

24V

 

 

RED

 

 

 

 

 

Main

GND

 

 

BLK

+ VDC

 

 

 

 

 

 

Out

LOW

 

 

GRA

 

 

+24-36 VDC In

4-20 Main Out

ECONO

MOTOR

ESL

damper system. The outdoor air enthalpy sensor is part of the enthalpy control. (The separate field-installed accessory return air enthalpy sensor (33CSENTSEN) is required for differential enthalpy control. See Fig. 36.)

Locate the enthalpy control in the economizer next to the Actuator Motor. Locate two GRA leads in the factory harness and connect the gray lead labeled “ESL” to the terminal labeled “LOW”. See Fig. 36. Connect the enthalpy control power input terminals to economizer actuator power leads RED (connect to 24V) and BLK (connect to GND).

C09027

Fig. 37 - Outside and Return Air Enthalpy Sensor

Wiring

To wire the return air enthalpy sensor, perform the following:

1.

Use a 2-conductor, 18 or 20 AWG, twisted pair cable

 

to connect the return air enthalpy sensor to the enthal-

 

py controller.

2.

Connect the field-supplied RED wire to (+) spade

 

connector on the return air enthalpy sensor and the

 

(+) terminal on the enthalpy controller. Connect the

Enthalpy

 

 

Switch

 

 

24V

RED

 

GND

BLK

 

LOW

GRA

ESL

 

 

7

ECONO MOTOR

CTB

ECON

BLK wire to (-) spade connector on the return air en-

thalpy sensor and the (-) terminal on the enthalpy

controller.

Indoor Air Quality (CO2 sensor) —

The indoor air quality sensor accessory monitors space carbon dioxide (CO2) levels. This information is used to monitor IAQ levels. Several types of sensors are available, for wall mounting in the space or in return duct, with and without LCD display, and in combination with space temperature sensors. Sensors use infrared technology to

Factory Wiring Harness

C09026

Fig. 36 - Enthalpy Switch (33CSENTHSW) Connections

The outdoor enthalpy changeover setpoint is set at the enthalpy controller.

measure the levels of CO2 present in the space air.

The CO2 sensors are all factory set for a range of 0 to 2000 ppm and a linear mA output of 4 to 20. Refer to the instructions supplied with the CO2 sensor for electrical requirements and terminal locations. See Fig. 38 for typical CO2 sensor wiring schematic.

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Carrier 50HCQA installation instructions Economizer Controls

50HCQA specifications

The Carrier 50HCQA is a cutting-edge rooftop air conditioning unit designed for commercial applications, combining efficiency, reliability, and advanced technology to ensure optimal indoor climate control. This model stands out in Carrier's extensive range of HVAC solutions, showcasing a blend of innovative features suitable for diverse building types.

One of the key features of the Carrier 50HCQA is its high-efficiency compressor. With variable-speed capabilities, the compressor adjusts its output to meet the precise cooling or heating demands of the space, promoting energy savings and consistent temperature management. This flexibility results in reduced energy consumption, making the 50HCQA an environmentally friendly choice for businesses looking to lower their carbon footprint.

The 50HCQA integrates advanced microprocessor controls, streamlining operation and enhancing user interaction. This technology allows for sophisticated diagnostics, monitoring, and scheduling, giving facility managers the tools they need to optimize system performance. The user-friendly interface ensures that settings can be easily adjusted, and real-time performance metrics can be accessed to ensure efficient operation.

In terms of construction, the Carrier 50HCQA is built with durability in mind. The unit features a robust cabinet design with a galvanized steel construction that is resistant to corrosion. This feature enhances the longevity of the unit, making it suitable for a variety of weather conditions. Additionally, the insulated casing reduces sound levels, providing a quieter operation that is particularly beneficial in noise-sensitive environments.

Another significant characteristic of the 50HCQA is its environmentally responsible refrigerant options. It utilizes R-410A refrigerant, which has a lower Global Warming Potential (GWP) compared to traditional refrigerants. This aspect not only meets regulatory standards but also supports users in making eco-friendly choices in their HVAC systems.

The 50HCQA also supports a range of optional accessories, including economizers for enhanced energy efficiency and improved air quality. This allows for increased outdoor air intake during suitable conditions, which can significantly contribute to enhancing indoor air quality—an essential factor for occupant comfort and health.

In conclusion, the Carrier 50HCQA is an exemplary model in the commercial HVAC sector, delivering powerful performance, advanced control technologies, and robust construction. Its energy-efficient design, user-friendly controls, and eco-conscious refrigerant options make it a top choice for businesses aiming to invest in sustainable and reliable climate control solutions.