Carrier 48LC User Manual

48LC
Single Package Rooftop
Gas Heating/Electric Cooling Unit
with Puronr (R---410A) Refrigerant
Size: 07
Installation Instructions
NOTE: Read the entire instruction manual before starting
the installation
TABLE OF CONTENTS
SAFETY CONSIDERATIONS 2....................
Rated Indoor Airflow (cfm) 3.....................
INSTALLATION 7...............................
Jobsite Survey 7................................
Step 1 -- Plan for Unit Location 7..................
Roof Mount 7...............................
Step 2 -- Plan for Sequence of Unit Installation 7......
Curb--Mount Installation 7.....................
Pad--Mount Installation 7......................
Frame--Mount Installation 7....................
Step 3 -- Inspect Unit 8...........................
Step 4 -- Provide Unit Support 8...................
Roof Curb Mount 8..........................
Slab Mount (Horizontal Units Only) 8...........
Alternate Unit Support
(In Lieu of Curb or Slab Mount) 10.............
Step 5 -- Field Fabricate Ductwork 10...............
Step 6 -- Rig and Place Unit 10....................
Positioning on Curb 10.......................
Step 7 -- Convert to Horizontal and Connect
Ductwork 11............................
Step 8 -- Install Outside Air Hood 12...............
Economizer Hood Package Removal and Setup —
Factory Option 12............................
Economizer Hood 12.........................
Step 9 -- Install Flue Hood 13.....................
Step 10-- Install Gas Piping 13.....................
Factory--Option Thru--Base Connections
(Gas Connections) 14.........................
Step 11 -- Install External Condensate Trap & Line 16...
Step 12 -- Make Electrical Connections 16...........
Field Power Supply 16........................
Units With Factory--Installed
Non--Fused Disconnect or HACR 21.............
Units Without Factory--Installed
Non--Fused Disconnect or HACR 22.............
All Units 22................................
Convenience Outlets 23.......................
HACR 24..................................
Factory--Option Thru--Base Connections
(Electrical Connections) 24....................
Units Without Thru--Base Connections 25........
Field Control Wiring 25.......................
Thermostat 25...............................
Unit without Thru--Base Connection Kit 25.......
Heat Anticipator Settings 25...................
RTU Open (Factory Option) 25..................
Integrated Staging Control (ISC) Board 26...........
ISC Board — Sequence of Operation 26...........
General 26.................................
Ventilation 26...............................
Cooling 27.................................
Economizer (Optional) 27.....................
Low Ambient Cooling Operation
Down to 40
_F(4_C) 27.......................
Heating 28.................................
EconoMi$er X (Factory Installed Option) 29.........
Unit Installation 29..........................
Enthalpy Sensor Relocation 29.................
W7220 Economizer Controller 29................
User Interface 29............................
Keypad 29.................................
Menu Structure 30.............................
Connections and Applications 35.................
W7220 Economizer Module Wiring 35..........
Economizer Control Configurations 36............
Enthalpy Changeover Control 36...............
Enthalpy Settings 36.........................
Demand Control Ventilation 38.................
Economizer Occupancy Control 39..............
Hardware 40.................................

Carrier 48LC Specifications

General

Brand	Carrier
Model	48LC
Category	Air Conditioner
Language	English

Summary

SAFETY CONSIDERATIONS

WARNING Hazards

Highlights critical safety warnings for fire, explosion, electrical shock, and unit operation.

INSTALLATION

Jobsite Survey and Planning

Covers jobsite survey, unit location, and installation sequence planning.

Unit Rigging and Placement

Procedures for lifting, moving, and positioning the unit on its support.

Piping and Ductwork Connections

Covers gas piping, condensate drainage, and basic ductwork installation.

Electrical Connections

Procedures for connecting field power supply and factory options.

Economizer X System

W7220 Economizer Controller

Covers the controller's features, user interface, and keypad navigation.

Economizer Control Configurations

Details enthalpy changeover and economizer settings for optimal operation.

Demand Control Ventilation (DCV)

Explains DCV function, CO2 sensors, and fan speed adjustments.

Variable Frequency Drive (VFD) Setup

VFD Keypad Operation and Connections

Explains VFD keypad layout, navigation, and connecting the keypad.

Program the VFD for Fan Speeds

Step-by-step guide to program VFD for 3 discrete fan speeds.

Smoke Detectors Installation

Return Air Smoke Sensor Installation

Instructions for completing the installation of return air smoke sensors.

Accessory Installation

Pre-Start and Start-Up Procedures

START-UP CHECKLIST

A comprehensive checklist for pre-start and operational verification.