Power Supply, Internal Wiring, Evaporator Fan

48/50PD

CONTROL BOX

AND

COMPRESSOR

ELECTRICAL

OPTIONS PANEL

INDOOR MOTOR

ACCESS DOOR

OUTDOOR AIR

SCREEN (HIDDEN)

CONDENSER COIL

ACCESS PANEL

GAS SECTION

ACCESS

FILTER ACCESS DOOR

BASEPAN CONNECTIONS

ACCESS PANEL

C07002

Fig. 4 - Panel and Filter Locations

On 3-phase units, it is important to be certain the compressors are rotating in the proper direction. To determine whether or not compressors are rotating in the proper direction, use a phase-rotation meter on the unit input power to check for L1-L2-L3 or clockwise rotation or use the Service Test mode to energize a compressor. If the compressor is rotating in the wrong direction, the controls will stop the compressor and display alarm for “Circuit A Failure to Pressurize.”

IMPORTANT: Indoor or outdoor fan rotation direction may not indicate proper input power phase sequence, as some 3-phase units use single-phase fan motors.

To correct the wrong compressor rotation direction, perform the following procedure:

1.Turn off power to the unit and lock out the power.

2.Switch any two of the incoming unit power leads.

3.Turn on power to the unit.

4.Verify corrected compressor rotation.

Power Supply

All 208/230-v units are factory wired for 230-v power supply. If the 208/230-v unit is to be connected to a 208-v power supply, the transformers (TRAN1 and TRAN2) must be rewired by moving the wire from the 230-volt connection and moving to the 200-volt terminal on the primary side of the transformer. Refer to unit label diagram for additional information.

Internal Wiring

Check all electrical connections in unit control boxes; tighten as required.

Evaporator Fan

Fan belt and variable pulleys are factory-installed, but may need to be adjusted for specific applications. Be sure that the fans rotate in the proper direction. See Appendix C for unit specific fan performance data. See Appendix D for unit specific air quality

limits, evaporator fan motor specifications, FIOP static pressures, and fan RPM for various motor pulley settings. Appendix C and D are based on 100% fan speed (VFD at 60Hz). To alter fan performance, see Evaporator Fan Performance Adjustment in the Service section.

The Supply Fan Minimum Speed (Configuration→UNIT→FS.MN) and the Supply Fan Maximum Speed (Configuration→UNIT→FS.MX) can also be used to alter fan performance. The fan should run at the maximum fan speed when setting up the application design point. The unit is equipped with a Variable Frequency Drive (VFD). The VFD’s settings should not be used for adjusting fan performance. Specific VFD information can be found in Appendix B.

IMPORTANT: When setting up and starting the unit, the heating minimum CFM requirements must be upheld when changing belts, pulleys, and configurations. During heating mode, the fan speed is always set to Supply Fan Maximum Speed (FS.MX).

Condenser Fans and Motors

Condenser fans and motors are factory set. Refer to Condenser-Fan Adjustment section as required.

Return-Air Filters

Check that correct filters are installed in filter tracks (see Physical Data table in Installation Instructions). Do not operate unit without return-air filters.

IMPORTANT: For units with 4-in. filter option, units are shipped with standard 2-in. filters. To install 4-in. filters, the filter spacers must be removed.

Outdoor-Air Inlet Screens

Outdoor-air inlet screens must be in place before operating unit.

48/50PD05 specifications

The Carrier 48/50PD05 is a remarkable addition to Carrier's lineup of rooftop units, offering advanced cooling and heating solutions for commercial applications. Designed for medium-sized buildings, this unit is well-suited for both new installations and as a replacement for older systems, thanks to its versatile features and efficient performance.

One of the standout features of the 48/50PD05 is its energy efficiency. It incorporates state-of-the-art technology to achieve high Seasonal Energy Efficiency Ratios (SEER) and EER ratings, reducing operational costs while delivering superior comfort. The unit is also compliant with the latest energy regulations, making it an environmentally friendly choice for building owners concerned about sustainability.

The 48/50PD05 is equipped with a highly efficient scroll compressor, which not only enhances performance but also contributes to quiet operation. This is a significant advantage in commercial spaces where noise levels need to be kept in check for comfort and productivity. Additionally, the unit includes advanced airflow design, ensuring even distribution of conditioned air throughout the space.

Technologically, the Carrier 48/50PD05 features Carrier's Infinity Control system, which allows for precise control of indoor climate. This intelligent control mechanism can be integrated with smart building management systems, enabling users to monitor and manage energy use effectively. Wi-Fi connectivity is also available, providing remote access for real-time adjustments and diagnostics.

Durability is another characteristic of the 48/50PD05. Constructed with high-quality materials, the unit withstands various environmental conditions, ensuring longevity and reliability. Moreover, the modular design facilitates easy maintenance, making service procedures efficient and cost-effective.

In addition to cooling, the Carrier 48/50PD05 offers heating capabilities, often utilizing gas or electric heating options that can be tailored to the specific needs of a building. The unit can also be equipped with integrated economizers, allowing for free cooling during suitable outdoor conditions, further enhancing energy savings.

Overall, the Carrier 48/50PD05 stands out as a high-performance HVAC solution that combines efficiency, technology, and durability. It provides building owners with a versatile tool to ensure comfort while minimizing their environmental footprint. With a strong emphasis on energy savings and advanced control features, this rooftop unit is a smart investment for any commercial property.