Hot Gas Bypass Ð An optional hot gas bypass system may be factory installed on circuit no. 1. This system will introduce discharge vapor from the compressor discharge line into the distributors and evaporator coil circuits on circuit no. 1 when suction pressures drop to damaging levels. No ®eld adjustments of the hot gas bypass valve should be required.

Condenser Fans Ð Each fan is supported by a formed wire mount bolted to fan deck and covered with a wire guard. The exposed end of the fan motor shaft is protected from weather by grease. If fan motor must be removed for service or replacement, be sure to regrease fan shaft and reinstall fan guard. For proper performance, fan should be 7¤8 in. (22 mm) below top of venturi on the fan deck to top of the fan hub. (See Fig. 64.) Tighten set screws to 15 ± 1 ft-lbs (20 ± 1.3 N-m). Figure 64 shows proper position of mounted fan.

NOTE: Fan rotation is clockwise when viewed from top of unit.

Fig. 64 Ð Condenser Fan Adjustment

IMPORTANT: Check for proper fan rotation (clock- wise viewed from above). If necessary to reverse, switch leads.

Compressor Removal Ð Access to the pump end of the compressor is from the compressor side of the unit. Access to the motor end of the compressor is from the inside of the unit. All compressors can be removed from the com- pressor side of the unit.

IMPORTANT: All compressor mounting hardware and support brackets removed during servicing must be re- installed prior to start-up.

1.Disconnect power to unit; lockout power to compressor.

2.Close suction and discharge service valves.

3.Relieve refrigerant pressure into a refrigerant recovery system.

4.Remove:

a.Fan-cycling pressure switch (FCPS)

b.High-pressure switch

c.Low-pressure switch

5.Disconnect power wires at terminal box and disconnect conduit.

6.Disconnect wires from crankcase heater.

7.Disconnect service valves from compressor.

NOTE: On units with 2 compressors per circuit, discon- nect both oil equalizer lines located on the motor barrel and on the oil pump sump.

8.Units 48/50MP62L:

a.Remove 4 large screws securing compressor mount- ing pan to unit base rail.

b.Slide compressor (on mounting pan) to outside of unit frame; support and/or lower to ground.

c.Unbolt compressor from mounting pan and remove.

9.Units 48/50MP70M,82N,90P,10R:

a.Remove 4 large screws securing compressor to the com- pressor rails.

b.Lift compressor off mounting bolts and remove.

Compressor Replacement Ð Perform the following:

1.Reverse procedure in Compressor Removal section to end of Step 4.

2.Reinstall service valves and safety switches, and tighten to torques as listed:

TORQUE

COMPRESSOR(S)

Tighten discharge valves to Ð

 

20-25 ft-lbs ( 27- 34 N-m)

06E-250

80-90 ft-lbs (109-122 N-m)

06E-265,275,299

Tighten suction valves to Ð

 

80- 90 ft-lbs (109-122 N-m)

06E-250

90-120 ft-lbs (122-163 N-m)

06E-265,275,299

Tighten the following ®ttings as speci®ed Ð

120 in.-lbs (13.5 N-m)

High-Pressure Switch

120 in.-lbs (13.5 N-m)

Low-Pressure Switch

3.Leak-check and evacuate system, reclaim refrigerant.

4.Recharge system per pre-start-up and start-up sequences. Recheck oil levels.

5.Energize crankcase heater for 24 hours prior to restart of system.

TROUBLESHOOTING

The 48/50MP units provide extensive troubleshooting in- formation to service personnel through the use of status codes and alarm and alert codes from the control system, which are displayed on the unit HSIO or through the use of Service Tool or CCN Building Supervisor. For more information on diagnostics, codes, and possible causes, refer to the Controls and Troubleshooting manual.

Use the Quick Test function to check control inputs and outputs (including economizer actuators). Refer to Controls and Troubleshooting Guide.

If there are indications of hunting (rapid oscillations) of control functions (such as duct static pressure or supply air temperature), or if the response rate is too slow, check the gain values. Refer to the Control Loop Checkout section on page 40 for more information.

If the unit is equipped with an optional VFD and the sup- ply or exhaust fan is not running when required, refer to the troubleshooting section of the separate VFD technical manual provided with the unit.

For troubleshooting information on mechanical systems, refer to the troubleshooting and diagnostics table on the next page.

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Carrier 50MP62L-10R, MPE62L-10R, 48MPD Compressor Replacement Ð Perform the following, Troubleshooting, Torque Compressors
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MPE62L-10R, 50MP62L-10R, 48MPD specifications

The Carrier 48MPD, 50MP62L-10R, and MPE62L-10R are advanced rooftop packaged units designed for a variety of commercial HVAC applications. These systems offer a compelling blend of energy efficiency, versatility, and high performance, making them ideal choices for businesses looking to enhance their indoor climate control.

One of the standout features of the Carrier 48MPD series is its high efficiency rating, which significantly reduces operational costs while minimizing environmental impact. The unit utilizes advanced scroll compressors that provide reliable and efficient cooling capabilities, ensuring optimal temperature regulation regardless of outdoor conditions. This innovative design also contributes to quieter operation, enhancing indoor comfort without disruptive noise levels.

The Carrier 50MP62L-10R model boasts superior cooling and heating capabilities, equipped with a multi-speed fan system that allows for tailored airflow to suit specific project requirements. This model's economizer feature is pivotal for harnessing outside air to offset mechanical cooling, leading to further energy savings, particularly in moderate weather conditions. Additionally, the unit's dual-fuel capability enhances its operational flexibility, allowing it to switch between electric and gas heating sources depending on efficiency needs.

In terms of control technologies, the MPE62L-10R is equipped with Carrier's advanced Smart Evaporator Control, which ensures precise humidity management while optimizing energy consumption. This model also integrates seamlessly with building automation systems, enabling remote monitoring and adjustments for greater operational oversight and efficiency. The intuitive user interface simplifies system programming and operation, making it accessible even for those without extensive technical backgrounds.

Another important characteristic of these units is their robust construction, designed to withstand challenging weather conditions and ensure longevity. The use of high-quality materials and components means lower maintenance costs over time.

Overall, the Carrier 48MPD, 50MP62L-10R, and MPE62L-10R represent a well-engineered suite of HVAC solutions that excel in efficiency, adaptability, and user-friendliness, establishing themselves as leading choices for commercial indoor climate management. With their blend of innovative technology and solid performance, these systems are well-suited to meet the diverse needs of modern commercial spaces.
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