7.Realign fan and motor pulleys:

a.Loosen fan pulley setscrews.

b.Slide fan pulley along fan shaft.

c.Make angular alignment by loosening motor from mounting plate.

8.Tighten belts.

9.Restore power to unit.

C06041

Fig. 31 - Evaporator-Fan Alignment and Adjustment

Evaporator Fan Belt Tension Adjustment

To adjust belt tension:

1.Turn off unit power.

2.Slide out fan deck to service position as shown in Evaporator Fan Service and Replacement section above.

3.Loosen motor mounting plate bolts.

4.Move motor mounting plate to adjust to proper belt tension. Motor adjuster bolts may be used to tighten belts. (See Fig. 30.) Do not overtighten belt.

5.Check for proper belt alignment. Adjust if necessary.

6.Tighten motor mounting plate bolts to lock motor in proper position.

7.Return fan deck back into operating position.

8.Restore power to unit.

Variable Frequency Drive (VFD) Replacement

The 48/50PD units are equipped with a VFD that is mounted behind the blower housing on the fan sled. The VFD’s remote display is mounted on the front of the fan housing for easier access. The VFD is mounted to a plate which is mounted to the fan sled. When accessing the VFD or to remove the VFD, follow the Evaporator fan service and replacement Steps 1-5 and the following steps:

IMPORTANT: If fan deck stop screws are removed for further access, the front of the fan deck MUST BE SUPPORTED.

1.Remove the 2 screws holding the VFD’s mount bracket to the fan sled. The horizontal cross section of the bottom half of the mount bracket is shown on Fig. 32.

2.Cut the wire ties holding the VFD power wires to the fan housing and the two wire ties holding the control wires to the VFD display/keypad at the top of the fan scroll.

3.With the VFD still attached, remove the mount bracket from the fan sled. To do this requires a slight lift on the screw side then a push towards the pulley side of the fan sled.

(See Fig. 32.) Lift out the bracket when the pulley side is clear from the fan sled.

4.With all the wires stilled attached to the VFD, turn the VFD assembly so it is parallel with the fan sled.

5.Pull the VFD assembly to the front of the fan sled and place in a secure flat surface.

6.Disconnect the power, ground, RJ45, and control wiring to the VFD making sure to note their connections.

IMPORTANT: Wires are marked with VFD terminal labels and wiring diagram shows the wiring connections.

7.

Remove the 4 screws holding the VFD to the mount bracket

 

 

and remove the VFD.

 

8.

Remove the replacement VFD cover and install jumper

 

 

wires provided with it as shown on the unit wiring diagram.

 

 

If jumpers are not provided with the replacement VFD,

 

 

remove them from the defective one or field supply the

 

 

 

 

jumpers.

 

9.

Set AI1 and AI2 DIP switches to the U (off) direction as

48/50PD

 

indicated on the plastic housing near the DIP switch.

10.

Replace the VFD with the new one.

 

11.

Install the 4 screws in the VFD to secure it to the mounting

 

 

bracket.

 

12.

Connect the wiring as it was on the previous VFD, refer to

 

 

the wiring diagram.

 

13.

Move the VFD assembly to the back of the fan sled.

 

14.

Turn the VFD assembly lengthwise with the fan housing,

 

 

making sure the screw side of the bracket lines up with the

 

 

screw holes on the fan sled.

 

15.

Make sure the bracket s pulley side U bend is clear of the

 

 

fan sled and pull the assembly towards the screw side.

 

16.

Install the 2 screws in the bracket to secure it to the fan sled.

 

17.

Secure power and control wires with new wire ties.

 

18.

Follow the Evaporator fan service and replacement Steps

 

 

6-9.

 

19.

Power up VFD and set up its parameters per Table 40 in

 

 

Appendix B.

 

IMPORTANT: If fan deck stops were removed, they must be reinstalled.

For VFD service and maintenance, refer to Appendix B.

C08662

Fig. 32 - VFD Mount Bracket Cross Section

Condenser-Fan Adjustment

1.Shut off unit power supply.

2.Remove condenser-fan assembly (grille, motor, motor cover, and fan) and loosen fan hub setscrews.

3.Adjust fan height as shown in Fig. 33.

4.Tighten setscrews and replace condenser-fan assembly.

5.Turn on power to unit.

63

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Carrier 48/50PD05 manual Evaporator Fan Belt Tension Adjustment, Variable Frequency Drive VFD Replacement
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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.
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