Carrier 38HQ 18-24 User Manual

SAFETY CONSIDERATIONS
Install and servicing air-conditioning equipment
can be hazardous due to system pressure and
electrical components. Only trained and qualified
service personnel should install or service air-
conditioning equipment untrained personnel may
perform basic maintenance such as cleaning and
replacing filters. All other operations should be
performed by trained service personnel. When
working on air conditioning equipment, observe
safety precautions in literature, and on tags and
labels attached to unit. Follow all safety codes.
Wear safety glasses and work gloves. Use
quenching cloth for brazing operations. Have a fire
extinguisher available. Read these instructions
thoroughly. Consult local building codes and
National Electrical Code (NEC) for special
installation requirements.
38HK 18-70
(50/60 Hz)
1-6 Nomin
Condensing Units
38HQ 18-24
Insta
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CONTENTS
Page
SAFETY CONSIDERATIONS …………………...………… .
INSTALLATION …………………………………….…………
Step 1 — Complete Pre-Installation Checks ……………
• UNPACK UNIT……………………………………………….
• INSPECT SHIPMENT……………………………………….
• CONSIDER SYSTEM REQUIREMENTS………………….
Step 2 — Rig and Mount Unit ……………………………
• MOUNTING ON GROUND…………………………………
• MOUNTING ON WALL…………………………………….
• MOUNTING ON ROOF………………………………………
• RIGGING……………………………………………………..
Step 3 — Complete Refrigerant Piping Connections …
• MAKE PIPING SWEAT CONNECTIONS………………….
• PROVIDE SAFETY RELIEF……………………………….
Step 4 — Make Electrical Connections ………………..
• POWER WIRING……………………………………………
• CONTROL CIRCUIT WIRING………………………………
• CONNECTIONS TO DUCT-FREE FAN COIL UNITS……..
Step 5 — Accessory Installation………………………….
START-UP……………………................................................
SERVICE ……………………………………………………
MAINTENANCE …………………………………………..
WIRING DIAGRAMS……………………………………….
TROUBLESHOOTING ……………………………………. .
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Carrier 38HQ 18-24 Specifications

General

Brand	Carrier
Model	38HQ 18-24
Category	Air Conditioner
Language	English

Summary

Safety Considerations

Unit Dimensions and Specifications

Physical and Performance Data

Electrical Data and Specifications

Installation Procedures

Pre-Installation Checks

Covers initial checks before unit installation.

Rigging and Mounting

Guidance on lifting, positioning, and securing the unit.

Refrigerant Piping Connections

Details on making refrigerant line connections.

Electrical Connections and System Integration

Electrical Connections

Instructions for power and control wiring.

Duct-Free Fan Coil Unit Integration

Information on connecting to specific indoor units.

Service and Maintenance Overview

Service Operations

Key service procedures and component checks.

Service Procedures and Components

Compressor Protection Systems

Details on relief valve, overload, and pressure switches.

Pumpdown Procedure

Steps to safely pump down the system for repairs.

Maintenance and Component Handling

Service Valve Handling

Information on the function and handling of service valves.

Routine Maintenance Tasks

Guidance on lubrication and coil cleaning.

Typical Wiring Schematics

Long-Line Application Guidelines

Approved Systems and Tubing Sizing

Lists approved units and recommends vapor-line diameters.

Long-Line Application Guidelines - Metering and Solenoids

Metering Device Sizing

Guidance on selecting metering devices for long-line systems.

Liquid-Line Solenoid Configuration

Information on liquid-line solenoid types and installation.

Long-Line Application Guidelines - Charging and Speed

Refrigerant Charging Information

Details on calculating additional refrigerant charge for long lines.

Two-Speed Application Differences

Discusses differences for 2-speed systems in long-line applications.

Pre-Start-Up Checklist

Outdoor Unit and Piping Checks

Pre-start-up checks for outdoor unit, power, and piping.

Indoor Unit and Control Checks

Checks for indoor unit piping, controls, and wireless remote.

Fan System and Power Supply Verification

Checks for fan rotation, air filters, and power supply.

Start-Up Procedures

Indoor Fan Operation Verification

Verifying indoor fan operation in different modes.

System Operation Observation

Observing outdoor unit operation after selecting cooling mode.