Carrier 48LC Series User Manual

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53480263-01 Printed in U.S.A. Form S-VU-LC-4-26-02T Pg 1 6-19 Replaces: S-VU-LC-4-26-01T
Controls, Start-Up, Operation, and
Troubleshooting
NOTE: This literature covers 48/50LC 04-26 models with Sys-
temVu controls version 3.X (factory-installed option).
CONTENTS
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . 2
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Conventions Used in This Manual . . . . . . . . . . . . . . . 3
BASIC CONTROL USAGE . . . . . . . . . . . . . . . . . . . . . . 3
SystemVu Control (factory-installed option). . . . . . . 3
SystemVu Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Accessory Navigator Display . . . . . . . . . . . . . . . . . . . 5
System Pilot™ and Touch Pilot™ Devices . . . . . . . . 7
CCN Tables and Display . . . . . . . . . . . . . . . . . . . . . . . 7
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Unit Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Refrigerant Service Ports . . . . . . . . . . . . . . . . . . . . . . 7
Crankcase Heater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Compressor Rotation . . . . . . . . . . . . . . . . . . . . . . . . . 7
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Internal Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Evaporator Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Condenser Fans and Motors. . . . . . . . . . . . . . . . . . . . 8
Return-Air Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Outdoor-Air Inlet Screens . . . . . . . . . . . . . . . . . . . . . . 8
Accessory Installation . . . . . . . . . . . . . . . . . . . . . . . . . 8
Gas Heat (48LC units only) . . . . . . . . . . . . . . . . . . . . 10
CONTROLS QUICK SET-UP . . . . . . . . . . . . . . . . . . . 10
Control Set Point and Configuration Log . . . . . . . . 10
Initial Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Thermostat Control . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Space Temperature Sensor Control - Direct
Wired (T-55 or T-56 or T-59) . . . . . . . . . . . . . . . . . 11
Space Humidistat Control . . . . . . . . . . . . . . . . . . . . . 11
Relative Humidity Sensor Control . . . . . . . . . . . . . . 11
CCN Communication . . . . . . . . . . . . . . . . . . . . . . . . . 11
CCN Linkage Control . . . . . . . . . . . . . . . . . . . . . . . . . 11
System Pilot™ – Communication Space Sensor . . 11
SystemVu™ Controller . . . . . . . . . . . . . . . . . . . . . . . 11
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Programming Operating Schedules . . . . . . . . . . . . . 12
SERVICE TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Independent Outputs . . . . . . . . . . . . . . . . . . . . . . . . . 13
Fan Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cooling Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Heating Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Automatic Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
THIRD PARTY CONTROL . . . . . . . . . . . . . . . . . . . . . 14
Cooling/Heating Control . . . . . . . . . . . . . . . . . . . . . . 14
Dehumidification Control . . . . . . . . . . . . . . . . . . . . . .14
Remote Occupancy . . . . . . . . . . . . . . . . . . . . . . . . . .14
Remote Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Alarm Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Economizer Damper Control . . . . . . . . . . . . . . . . . . .14
CONTROLS OPERATION . . . . . . . . . . . . . . . . . . . . . .14
Display Configuration. . . . . . . . . . . . . . . . . . . . . . . . .14
Unit Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . .15
GENERAL OPERATION . . . . . . . . . . . . . . . . . . . . . . .15
Demand Determination. . . . . . . . . . . . . . . . . . . . . . . .16
Occupancy Determination . . . . . . . . . . . . . . . . . . . . .17
Indoor Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . .18
Cooling Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Optional Humidi-MiZer Dehumidification System . .21
Indoor Fan Based Dehumidification . . . . . . . . . . . . .25
Heating Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Supply Air Tempering. . . . . . . . . . . . . . . . . . . . . . . . .26
Economizer Operation . . . . . . . . . . . . . . . . . . . . . . . .27
Power Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Indoor Air Quality (IAQ) . . . . . . . . . . . . . . . . . . . . . . .30
Pre-occupancy Purge . . . . . . . . . . . . . . . . . . . . . . . . .31
Temperature Compensated Start . . . . . . . . . . . . . . .31
Linkage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Carrier Comfort Network® (CCN) Operation . . . . . .31
BACnet Network Operation . . . . . . . . . . . . . . . . . . . .32
Alarm Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . .32
Complete Unit Stoppage . . . . . . . . . . . . . . . . . . . . . .32
Restart Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Faults and Alerts. . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Control Module Communication . . . . . . . . . . . . . . . .40
Communication Failures . . . . . . . . . . . . . . . . . . . . . .40
Cooling Troubleshooting . . . . . . . . . . . . . . . . . . . . . .40
Humidi-MiZer® System Troubleshooting . . . . . . . . .41
Economizer Troubleshooting . . . . . . . . . . . . . . . . . .43
Heating Troubleshooting . . . . . . . . . . . . . . . . . . . . . .44
Phase Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Thermistor Troubleshooting . . . . . . . . . . . . . . . . . . .47
Sensor Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Transducer Troubleshooting . . . . . . . . . . . . . . . . . . .48
MAJOR SYSTEM COMPONENTS . . . . . . . . . . . . . . .48
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Main Base Board (MBB) . . . . . . . . . . . . . . . . . . . . . . .67
Input-Output Board (IOB). . . . . . . . . . . . . . . . . . . . . .69
Integrated Gas Control (IGC) Board . . . . . . . . . . . . .70
Protective Devices . . . . . . . . . . . . . . . . . . . . . . . . . . .71
Space Mounted Sensors . . . . . . . . . . . . . . . . . . . . . .71
48/50LC 04-26
Single Package Rooftop Units
with SystemVu™ Controls Version 3.X
and Puron
®
(R-410A) Refrigerant

Carrier 48LC Series Specifications

General

Brand	Carrier
Model	48LC Series
Category	Air Conditioner
Language	English

Summary

SAFETY CONSIDERATIONS

GENERAL SYSTEM INFORMATION

Manual Conventions and Basic Control Usage

Explains manual conventions, SystemVu interface, and fundamental control operations.

SystemVu Controller and Navigator Display Overview

Details the SystemVu interface, Navigator display, and related devices for unit control.

UNIT START-UP AND CONFIGURATION

Pre-Start-Up Checks and Preparations

Covers electrical, refrigerant, and component checks before initial unit start-up.

Initial Control System Setup

Guides through quick setup, network configuration, and system auto-tests.

SystemVu Controller Configuration Parameters

Details settings for thermostat, CCN, System Pilot, and accessories.

OPERATING MODES AND CONTROL LOGIC

Service Test Procedures and Modes

Outlines diagnostic tests for various unit components and operational modes.

Dehumidification, Economizer, and Air Quality Control

Explains the operation and configuration of dehumidification, economizer, and IAQ functions.

Demand Determination and Occupancy Control

Details how unit demand is calculated and occupancy affects operation.

TROUBLESHOOTING AND ALARMS

System Alarms, Faults, and Alerts

Explains how to view, interpret, and clear system alarms and faults.

Component-Specific Troubleshooting

Covers troubleshooting for VFDs, economizers, heating systems, and communication issues.

Major System Components and Service Analysis

Provides diagrams and tables for analyzing component performance and service issues.