Install Motormaster® III Controls — Only one Motormaster III control is required per unit.

Motor — One outdoor-fan motor (OFM) must be changed out in the field to accommodate the Motormaster III accessory. The replacement motor part no. is HD52AK652.

For 48AJ,AK,AW,AY020-030 and 48EJ,EK,EW,EY024- 034 units, the Motormaster controlled OFM is the no. 2 OFM and is located at the left side of the unit looking from the com- pressor end. The no. 1 OFM is controlled to shut off at 55 F and on at 65 F outdoor-air temperature and does NOT need to be changed out.

For 48AJ,AK,AW,AY035-050 and 48EJ,EK,EW,EY038- 054 units, the Motormaster controlled OFM is no. 1 OFM and is located at the left side of the unit looking from the compres- sor end and the second motor back. The no. 3 and 4 OFM are controlled to shut off at 55 F and on at 65 F outdoor-air temper- ature and do NOT need to be changed out. The no. 2 OFM is intended to run at all ambient temperatures.

For 48AJ,AK,AW,AY060 and 48EJ,EK,EW,EY058-068 units, the Motormaster controlled OFM is no. 3 OFM and is lo- cated at the left side of the unit looking from the compressor end and the second motor back.

The no. 4, 5, and 6 OFMs are controlled to shut off at 55 F and on at 65 F outdoor-air temperature and do NOT need to be changed out. The no. 1 and 2 OFMs are intended to run at all ambient temperatures.

Sensor — Install the sensor for thermistor input control in the location shown in Fig. 53A-53E. Connect sensor leads to the violet and gray control signal leads on the Motormaster III control.

Signal Selection Switch — Remove the cover of the Motor- master III control. Set the switch to accept the thermistor sensor input signal. Set the frequency to match the unit power supply (60 Hz).

Motormaster III Control — The recommended mounting loca- tion is in the indoor fan section, mounted on the panel that sep- arates the indoor and outdoor sections. On VAV units, this location is next to the VFD (variable frequency drive).

Do not route the Motormaster III control wiring next to the VFD on VAV units. Use a separate connector through the parti- tion when wiring to the OFM.

Electrical Connections

To avoid possibility of electrical shock and personal injury, turn off all power to unit before making electrical connections.

When replacing the OFM, reconnect the black, yellow, and blue wires form the outdoor fan contactor to the black, yellow, and blue wires of the Motormaster III control. Run new wires from the red, orange, and brown wires to the leads of the new OFM. Connect the green wire from the control to ground.

NOTE: On all 575-v units, 2 transformers (part no. HT01AH851) must be used for each Motormaster III control to lower the supply voltage to the control to 460-v. Transform- ers can be mounted anywhere outside the control box.

1 BOTH SIDES

18

B

0.312 DIA HOLES

61

17.167

 

BETWEEN

 

HOLES

 

(TYPICAL)

CROSS-BREAK

A

0.5

4.62

 

UNIT SIZE

A

B

48AJ,AK,AW,AY020-050 and

80.5

79.5

48EJ,EK,EW,EY024-054

 

 

48AJ,AK,AW,AY060 and

120.5

119.5

48EJ,EK,EW,EY058-068

 

 

NOTE: All dimensions are in inches. Material: 20 gage galvanized steel or other non-corrosive material.

Fig. 52 — Motormaster III Control Baffle Details

Fig. 53A — Motormaster III Sensor Location

(48AJ,AK,AW,AY020-030 and

48EJ,EK,EW,EY024-034)

55

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Carrier 48EW, 48EY024-068, 48AW, 48AY020-060 Unit Size, 80.5 79.5 48EJ,EK,EW,EY024-054, 120.5 119.5 48EJ,EK,EW,EY058-068
Page 54 Page 56

48EJ, 48AJ, 48AK, 48EK, 48AY020-060 specifications

The Carrier 48EJ, 48AW, 48EK, 48AJ, and 48EY024-068 are cutting-edge rooftop air conditioning units designed for commercial applications. These models are renowned for their reliability, energy efficiency, and innovative technologies aimed at providing optimal indoor comfort.

One of the standout features of these units is their advanced cooling and heating capabilities. They employ a multi-stage compressor system that allows for precise temperature control, accommodating various load requirements. This flexibility is particularly beneficial in commercial settings where the cooling load can fluctuate throughout the day.

Energy efficiency is paramount in today’s environmental landscape, and Carrier has ensured that these models meet stringent efficiency standards. They incorporate high-efficiency scroll compressors, which significantly reduce energy consumption while delivering powerful performance. The units are also equipped with variable speed fans that adjust airflow based on demand, further optimizing energy use.

In terms of construction, these rooftop units feature a robust design that enhances durability and longevity. The cabinet is constructed to withstand harsh weather conditions, ensuring reliable performance year-round. Additionally, the units are equipped with corrosion-resistant coatings, particularly useful in coastal environments where salt exposure can be a concern.

The Carrier 48EJ, 48AW, 48EK, 48AJ, and 48EY models utilize advanced controls and connectivity features, allowing for easy integration into building management systems. This connectivity enables remote monitoring and control, facilitating quick response to changing conditions and simplifying maintenance tasks.

Noise reduction is another key characteristic of these models. They are designed with sound-absorbing insulation and low-noise fan blades to ensure quiet operation, making them suitable for noise-sensitive environments such as schools and hospitals.

These units are also available with various options for air filtration and dehumidification. The use of high-efficiency air filters enhances indoor air quality by trapping dust, pollen, and other airborne particles. Enhanced dehumidification capabilities ensure that spaces remain comfortable even in humid conditions.

In conclusion, the Carrier 48EJ, 48AW, 48EK, 48AJ, and 48EY024-068 rooftop units are engineered to offer exceptional performance, energy efficiency, and durability. With their advanced technologies and user-friendly features, they stand out as reliable solutions for meeting diverse commercial cooling and heating needs, making them a popular choice for many businesses.
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