Carrier 38MAQB24R-3 - User Manual

20 pages

Save Page as PDF

To Next Page

Specifications subject to change without notice.

Fig. 1 —Sizes 9K to 36K

NOTES: Read the entire instruction manual before starting the

installation.

Images are for illustration purposes only. Actual

models may differ slightly.

TABLE OF CONTENTS

PAGE

SAFETY CONSIDERATIONS........................................................2

INTRODUCTION ............................................................................3

ACCESSORIES................................................................................3

DIMENSIONS..................................................................................4

CLEARANCES ................................................................................7

INSTALLATION REQUIREMENTS .............................................8

INSTALLATION .............................................................................8

Step 1 - Check Equipment ................................................................8

Step 2 - Mount Unit ..........................................................................8

Step 3 - Condensate Drain Installation .............................................9

Step 4 - Refrigerant Piping ...............................................................10

Step 5 - Evacuate Coil And Tubing System .....................................13

Step 6 - Electrical Connections.........................................................14

WIRING ...........................................................................................14

ELECTRICAL DATA......................................................................15

CONNECTION DIAGRAMS ..........................................................15

START-UP .......................................................................................16

CARE AND MAINTENANCE........................................................16

TROUBLESHOOTING ...................................................................16

OUTDOOR UNIT DIAGNOSTIC GUIDES ...................................17

DUCTLESS START-UP CHECKLIST ...........................................18

Installation Instructions

38MA*R

Outdoor Unit Single Zone Ductless System

Sizes 09 to 36

Questions and Answers

L
Luis WashingtonAug 3, 2025
What to do if Carrier Air Conditioner shows high/low voltage protection on compressor terminal?
- V
  vvanceAug 4, 2025
  If your Carrier Air Conditioner's compressor terminal shows high or low voltage protection errors, the first step is to check the voltage levels. Ensure that the power supply to the unit is stable and within the recommended range.

Summary

Safety Considerations

Hazard Warnings and Precautions

Specific safety warnings including electrical, explosion, and equipment damage hazards.

Installation Steps Part 3

Step 4: Refrigerant Piping

Instructions for running, cutting, and flaring refrigerant piping.

Installation Steps Part 4

Step 6: Connect the Pipes

Connecting refrigerant pipes to the indoor and outdoor units.

Step 7: Pressure Test Piping

Testing the refrigerant lines for leaks using nitrogen pressure.

Installation Steps Part 5

Step 5: Evacuate Coil and Tubing System

Procedure for removing air and moisture from the refrigerant circuit.

Installation Steps Part 6

Step 6: Electrical Connections

Wiring the outdoor unit power supply and communication lines.

Troubleshooting

Unit Diagnostic Guides

Explanation of diagnostic codes and LED indicators for troubleshooting.

Outdoor Unit Diagnostic Guides

Ductless Start-Up Checklist (Continued)

Piping and Evacuation Verification

Performance and Error Code Reporting

The 38MA*R Outdoor Unit is a single-zone ductless system designed for air-conditioning applications, available in sizes ranging from 09 to 36. These units are R-410A condensing units, featuring an inverter-driven compressor that operates at various input power frequencies (Hz) to control motor speed, ensuring application flexibility and efficient operation.

Function Description:

The primary function of the 38MA*R Outdoor Unit is to provide cooling and heating (if applicable) for single-zone ductless systems. It works in conjunction with an indoor unit, circulating R-410A refrigerant to transfer heat between the indoor and outdoor environments. The inverter-driven compressor allows for variable capacity operation, which contributes to energy efficiency and precise temperature control. The unit is designed for horizontal discharge, optimizing airflow and installation flexibility.

Important Technical Specifications:

The 38MA*R Outdoor Unit is available in several capacities, ranging from 0.75 tons (9,000 BTUH) to 3.00 tons (36,000 BTUH). Voltage options include 115V (for 1.00 ton/12,000 BTUH models) and 208/230V (for all other capacities). All models operate on a single-phase, 60 Hz power supply.

Dimensions and Weight:

9K-12K (115V and 208/230V):
- Height (H): 21.81 in (554 mm)
- Width (W): 32.09 in (815 mm)
- Depth (D): 13.11 in (333 mm)
- Operating Weight: 82.9 lbs (37.6 kg) for 115V, 91.5 lbs (41.5 kg) for 208/230V.
18K (208/230V):
- Height (H): 27.63 in (702 mm)
- Width (W): 33.66 in (855 mm)
- Depth (D): 14.17 in (360 mm)
- Operating Weight: 118.2 lbs (53.6 kg)
24K-36K (208/230V):
- Height (H): 31.89 in (810 mm)
- Width (W): 37.24 in (946 mm)
- Depth (D): 16.14 in (410 mm)
- Operating Weight: 145.5 lbs (66 kg) for 24K, 139.8 lbs (63.4 kg) for 30K, 147.3 lbs (66.8 kg) for 36K.

Refrigerant Piping:

Minimum piping length: 10 ft (3 m).
Standard piping length: 25 ft (7.5 m).
Maximum piping length: 82 ft (25 m) for 9K-18K models, 164 ft (50 m) for 24K-36K models.
Maximum outdoor-indoor height difference: 32 ft (10 m) for 9K-12K models, 65 ft (20 m) for 18K-24K models, 82 ft (25 m) for 30K-36K models.
Liquid pipe sizes: 1/4 in (6.35 mm) for 9K-18K, 3/8 in (9.52 mm) for 24K-36K.
Gas pipe sizes: 1/2 in (12.7 mm) for 9K-18K, 5/8 in (16 mm) for 24K-36K.
Additional refrigerant charge (between standard and max piping length) varies by model, e.g., 0.16 oz/ft (15 g/m) for 9K-18K, 0.32 oz/ft (30 g/m) for 24K-36K.
Refrigerant type: R-410A.
Factory charge amount: 2.76 lbs (1.25 kg) for 12K (115V), 3.31 lbs (1.5 kg) for 9K-12K (208/230V), 4.30 lbs (1.95 kg) for 18K, 5.73 lbs (2.60 kg) for 24K, 6.06 lbs (2.75 kg) for 30K, 7.50 lbs (3.40 kg) for 36K.

Electrical Data:

Minimum Circuit Amps (MCA) and Maximum Over-Current Protection (MOCP) values are provided for each model.
Rated Load Amps (RLA) for the compressor and Full Load Amps (FLA) for the outdoor fan motor are specified.
Connection cable size: 14AWG (3 wire + Ground, 208/230V, stranded wire recommended).

Usage Features:

Installation Flexibility: Designed for various applications with a significant maximum piping length and lift, allowing for flexible placement of indoor and outdoor units.
High Wind Installation: Can be installed with the air inlet side facing a wall to prevent high wind exposure.
Condensate Management: Features a basepan with multiple holes for draining during defrost. A drain joint and hose are provided to redirect condensate, especially in heating mode, to prevent water damage. Rubber plugs are available for sealing basepan holes if required.
Electronic Expansion Valve: All outdoor units are equipped with an electronic expansion valve to manage refrigerant flow to the connected fan coil, optimizing performance.
Quiet Operation: Grommets are included to secure the outdoor unit and help prevent vibration during operation.
Diagnostic Display: Equipped with diagnostic code display LEDs (Red and Green) on the outdoor unit board for ease of service and troubleshooting. These LEDs indicate various operational statuses and error conditions, such as high/low voltage protection, EEPROM errors, compressor speed issues, and communication errors.

Maintenance Features:

Periodic Maintenance: To ensure high performance and minimize equipment failure, periodic maintenance is recommended. The frequency may vary based on geographic areas.
Troubleshooting Guides: The manual provides detailed diagnostic guides, including LED status codes (E1, F0-F5, P0-P4, P7, J0-J5, JL, J8) that correspond to specific malfunctions like communication errors, overcurrent protection, sensor faults, fan speed issues, and voltage protection. This aids technicians in quickly identifying and resolving problems.
Leak Check and Evacuation: Comprehensive instructions are provided for pressure testing the refrigerant piping using dry nitrogen and evacuating the coil and tubing system using either the deep vacuum method (500 microns) or the triple evacuation method, ensuring a tight and dry system.
Component Accessibility: The design allows for access to components for service, with recommended clearances around the unit for proper airflow and maintenance.
Wiring Accessibility: The field wiring cover can be removed for easy access to electrical connections and terminal blocks.

Safety Considerations:

The manual emphasizes safety, highlighting potential hazards related to system pressures, electrical components, and equipment location. It mandates that installation, start-up, and servicing be performed by trained, qualified installers and service mechanics. Warnings are provided against electrical shock, explosion hazards (due to using air or oxygen for leak testing), and equipment damage (from improper installation, contamination, or burying refrigerant pipes excessively). Clearances are specified to ensure proper airflow and service access, and precautions are detailed for working with refrigerant piping, including proper cutting, deburring, flaring, and tightening procedures. The use of dry nitrogen for pressure testing is strictly enforced to prevent injury or property damage.

Carrier 38MAQB24R-3 Specifications

General

Refrigerant	R-410A
Voltage	208/230V
Phase	1
Compressor Type	Inverter
Stages	Variable
Outdoor Unit Noise Level	55 dB(A)
Cooling Capacity	24000 BTU/h
Heating Seasonal Performance Factor (HSPF)	10.0
Operating Temperature (Cooling)	5°F - 122°F
Outdoor Unit Dimensions (H x W x D)	35.4 x 12.6 inches