Carrier Infinity 25VNA8 User Manual

Service Manual
25VNA8 Infinityr 18V S Variable Spee d Heat Pump
24VNA9 Infinityr 19VS Variable Speed Air Conditioner
with Puronr Refrigerant
TABLE OF CONTENTS
PAGE
UNIT IDENTIFICATION 2.................................................................................
REFRIGERANT PIPING LENGTH LIMITATIONS 3...........................................................
LONG LINE APPLICATIONS 3.............................................................................
SAFETY CONSIDERATIONS 4.............................................................................
GENERAL INFORMATION 4..............................................................................
ELECTRICAL 5..........................................................................................
MAJOR COMPONENTS 5--7...............................................................................
AOC Board 5..........................................................................................
Inverter 5..............................................................................................
Variable Speed Compressor 5..............................................................................
Electronic Expansion Valve (EXP) 6.........................................................................
Outdoor Fan Motor 6.....................................................................................
Pressure Transducer (SPT) 6...............................................................................
Pressure Equalizer Valve (PEV) 6...........................................................................
Outdoor Coil Thermistor (OCT) 6...........................................................................
Suction Thermistor (OST) 7...............................................................................
Discharge Thermistor (ODT) 7.............................................................................
Crankcase Heater 7......................................................................................
Time--Delays 7.........................................................................................
COMMUNICATION AND STATUS FUNCTION LIGHTS 7.....................................................
CHECK CHARGE 9.......................................................................................
TROUBLESHOOTING 9--13................................................................................
Service Tool 14--34......................................................................................
System Communication Failure 14..........................................................................
Model Plug 14..........................................................................................
Status Codes 14.........................................................................................
Variable Speed Compressor Winding Resistance 15.............................................................
Fan Motor 16...........................................................................................
Brown Out Protection 16..................................................................................
230v Line (Power Disconnect) Detection 16...................................................................
Pressure Switch Protection 16..............................................................................
Suction Pressure Transducer (SPT) 16........................................................................
Temperature Thermistors 17...............................................................................
Fault Code Action Table 19................................................................................
Variable Speed Drive LED Location and Description 28..........................................................
Compressor Power Harness Assembly Replacement 29..........................................................
Inverter Assembly with Shield Gasket Installation 31............................................................
Compressor Replacement 34...............................................................................
WIRING DIAGRAMS 37--38.................................................................................
REFRIGERATION SYSTEM 39--43..........................................................................
Refrigerant 39..........................................................................................
Compressor Oil 39.......................................................................................
Servicing Systems on Roofs With Synthetic Materials 39.........................................................
Brazing 39.............................................................................................
Service Valves and Pump down 39..........................................................................
Liquid Line Filter Drier 42................................................................................
Suction Line Filter Drier 42................................................................................
Thermostatic Expansion Valve (TXV) 42.....................................................................
Accumulator 43.........................................................................................
REFRIGERATION S YSTEM REPAIR 43.....................................................................

Carrier Infinity 25VNA8 Specifications

General

Type	Heat Pump
Cooling Capacity	24, 000 - 60, 000 BTU/h
Heating Capacity	24, 000 - 60, 000 BTU/h
SEER Rating	Up to 20.5
Compressor Type	Variable Speed
Refrigerant	R-410A
Wi-Fi Enabled	Yes
Number of Stages	Variable

Summary

Unit Identification and Nomenclature

Safety Considerations and General Information

Safety Warnings and Precautions

Covers electrical, cut, explosion, and general operating safety hazards.

Electrical System and Major Components

Electrical Hazards and Precautions

Refrigerant Charge Check Procedures

Charging in Cooling Mode (Communicating)

Guides charging via UI for communicating systems.

Charging Non-Communicating Systems

Outlines charging procedures for non-communicating thermostats.

Troubleshooting Overview and Diagnostics

Service Tool and Communication Issues

Covers using the service tool and diagnosing communication failures.

Status Codes and Fault Diagnosis

Details status codes, recall mode, and interpreting amber LED flashes.

Troubleshooting Specific Components

Variable Speed Compressor Winding Resistance

Provides steps and values for checking compressor winding resistance.

Fan Motor Resistance Testing

Protection Features: Brown-Out and Line Voltage

High Pressure Switch Protection

Describes the high-pressure switch function and system response.

Suction Pressure Transducer (SPT) Verification

Thermistor Monitoring and Inverter Over-Temperature

Inverter Over-Temperature Protection

Describes inverter temperature sensing and mitigation response.

Fault Code Reference and Interpretation

Amber LED Fault Code Label

Explains how amber LED flashes represent fault codes.

Fault Code Actions and Troubleshooting Steps

Provides a table of fault codes, causes, and actions.

Variable Speed Drive LED Indicators

LED Locations and Descriptions (Sizes 13 & 24B)

Variable Speed Drive LED Indicators (Sizes 25-60)

LED Locations and Descriptions (Sizes 25-60)

LED Functionality and UI Fault Codes

Compressor Power Harness Assembly Replacement

Safety Warnings for Harness Replacement

Emphasizes electrical shock hazards and capacitor discharge.

Compressor Power Harness Replacement Procedure

Step-by-step guide for replacing the compressor power harness.

Inverter Assembly Removal and Installation

Safety Precautions for Inverter Service

Covers electrical hazards and capacitor discharge before inverter service.

Inverter Removal and Installation Procedure

Detailed steps for removing and installing the inverter assembly.

Compressor Replacement Procedures

Safety Warnings for Compressor Replacement

Highlights electrical shock, personal injury, and unit damage hazards.

Mechanical Failure Compressor Replacement

Refrigeration System Overview

Refrigerant and Compressor Oil Handling

Covers refrigerant type, pressures, and POE oil properties.

Service Valves and Pumpdown Basics

Refrigeration System Repair Procedures

Pumpdown and Evacuation Procedures

Details pumpdown and evacuation steps for various system configurations.

Reversing Valve Operation and Replacement

Refrigeration System Components

Filter Drier Installation and Function

Thermostatic Expansion Valve (TXV) Operation

Accumulator and Leak Detection

Leak Detection Methods