Carrier 38AUQ Service Manual

Installation, Start-Up
and Service Instructions
CONTENTS
SAFETY CONSIDERATIONS .................... 2
INSTALLATION GUIDELINES .................. 3
INSTALLATION ........................... 7- 16
Step 1 - Plan for Unit Location .................. 7
Step 2 - Complete Pre-Installation Checks ......... 8
Step 3 - Prepare Unit Mounting Support ........... 8
Step 4 - Rig and Mount the Unit ................. 8
Step 5 - Complete Refrigerant Piping Connections... 8
Step 6 - Install Accessories .................... 12
Step 7 - Complete Electrical Connections ......... 12
PRE-START-UP ............................... 17
System Checks .............................. 17
Turn On Crankcase Heaters .................... 17
Preliminary Charge ........................... 17
START-UP .............................. 17 - 20
38AUQ Units ............................... 17
OPERATING SEQUENCE ...................... 21
Indoor (Supply) Fan .......................... 21
Cooling Unit Without Economizer ............... 21
Cooling Unit With Economizer ................. 21
Defrost Cycle ............................... 21
Supplemental Heating/Emergency Heating ........ 22
Cooling and Heating Shutdown ................. 22
ROUTINE SYSTEM MAINTENANCE ............ 22
Quarterly Inspection
(and 30 days after initial start) .................. 22
SERVICE ................................ 23 - 35
Refrigeration System ......................... 23
Compressor Oil .............................. 23
Servicing Systems on Roofs
with Synthetic Materials ....................... 23
Liquid Line Filter Driers ....................... 23
Filed Refrigerant Access Ports .................. 23
Outdoor Coil Metering Devices ................. 23
Refrigerant System Pressure Access Ports ......... 24
Compressor Protection ........................ 24
Crankcase Heater ............................ 24
Commercial Defrost Board ..................... 24
Comfort Alert Diagnostic Module ............... 31
Lubrication ................................. 33
Outdoor Coil Maintenance and
Cleaning Recommendations .................... 33
Service Parts ................................ 35
Fastener Torque Values ........................ 35
TROUBLESHOOTING ......................... 36
APPENDIX A
Air Conditioner and Heat Pump with Puron _n_-
Quick Reference Guide ........................ 37
APPENDIX B
Wiring Diagram List .......................... 37
APPENDIX C
Low Ambient Option -- Factory Installed ......... 38
START-UP CHECKLIST ................... 43 - 44

Carrier 38AUQ Specifications

General

Brand	Carrier
Model	38AUQ
Category	Heat Pump
Language	English

Summary

Safety Considerations

Installation

Jobsite Survey

Conducting a site assessment to determine the optimal unit location, considering clearances and support.

Step 1 Plan for Unit Location

Pre-Start-Up

System Check

Verifying unit electrical characteristics, leak checks, dehydration, and component connections before operation.

Turn On Crankcase Heater

Energizing the crankcase heater for 24 hours to ensure refrigerant removal from oil before compressor start.

Preliminary Charge

Adding liquid refrigerant to the system's high side before starting to prevent compressor damage.

Start-Up

Preliminary Checks

Ensuring power supply, crankcase heater operation, leak checks, and wiring are correct before unit start.

Compressor Rotation

Verifying correct compressor rotation direction, especially for 3-phase units, using CADM and pressure checks.

Operating Sequence

Cooling Unit Without Economizer

Heating

Operation sequence for heating mode, including Stage 1 heat and defrost cycle initiation.

Defrost Cycle

Details the process of clearing frost and ice from the outdoor coil by reversing the cycle.

Service

Refrigeration System

Important considerations for handling Puron® refrigerant, including pressure and equipment compatibility.

Compressor Oil

Information on POE oil, its hygroscopic nature, and precautions for handling to avoid moisture absorption.

Liquid Line Filter Drier

Compressor Protection

Commercial Defrost Control

Comfort Alert Diagnostic Module

Troubleshooting