Carrier AC310 User Manual

Transport Air Conditioning
T--304 Rev A Change 07/09
OPERATION AND SERVICE
for
MODELS AC310 & AC350
Rooftop Air Conditioning Units
With
BT324 Carrier Sutrak Digital Display (CSDD)
or
280P/282P Electronic Thermostat

Carrier AC310 Specifications

General

Brand	Carrier
Model	AC310
Category	Air Conditioner
Language	English

Summary

SAFETY SUMMARY

General Safety Notices

General safety notices supplement specific warnings and cautions appearing elsewhere in this manual.

First Aid Procedures

Procedures for immediate medical attention for injuries sustained, no matter how slight.

Operating Precautions

Safety measures to follow during unit operation, including eye protection and keeping clear of fans.

Maintenance Precautions

Safety measures to follow during unit maintenance, including power disconnection and tool safety.

SPECIFIC WARNINGS AND CAUTIONS

Warning: HVAC System Maintenance

Observe warnings listed in the safety summary before performing maintenance on the HVAC system.

Warning: Pre-Operation Checks

Read the entire procedure, park vehicle on a level surface, apply parking brake, and turn off disconnect switch.

Warning: Nitrogen Cylinder Use

Do not use a nitrogen cylinder without a pressure regulator.

Warning: Oxygen Use Near Refrigeration System

Do not use oxygen in or near a refrigeration system as an explosion may occur.

Warning: Filter-Drier Refrigerant Handling

The filter-drier may contain liquid refrigerant; slowly loosen nuts and avoid skin contact.

Caution: Service Port Couplings

AC310/AC350 systems have R134a service port couplings and 1/4 inch flare fittings.

Caution: Liquid Refrigerant Trapping

Ensure manifold gauge set is at suction pressure before disconnecting to prevent trapping liquid refrigerant.

SECTION 1 DESCRIPTION

1.1 Introduction

This section covers operating instructions, service instructions, and electrical data for AC310/AC350 units.

1.2 General Description

Provides an overview of the rooftop unit, including its sections and main components.

1.2.1 Rooftop Unit Components

Describes the rooftop unit containing the condensing section and the evaporator section.

1.2.2 Condensing Section Components

Details components of the condensing section, including coils, fans, filter-driers, and receivers.

1.2.3 Evaporator Section Components

Details components of the evaporator section, including coils, blowers, and expansion valves.

1.2.4 Drivers Evaporator (Optional)

Describes the optional driver's evaporator installed in the vehicle dash.

1.2.5 Compressor Assembly Details

Explains dual and single loop compressor assemblies and their components.

1.2.6 System Operating Controls and Components

Covers electronic thermostats and manual switches controlling system operation.

1.2.7 280P & 282P Electronic Thermostat Controller

Information on the three-mode thermostat controller for cooling, vent, and heat.

1.2.8 CSDD BT-324 Microprocessor Controller

Details the BT-324 controller's modes: Auto, Vent, and Heat.

1.2.9 Optional Motor Fault Board

Describes the motor fault board indicating motor status via LEDs.

1.3 Refrigeration System Component Specifications

Lists specifications for refrigerant charge and component capacities.

1.4 Electrical Specifications - Motors

Provides specifications for evaporator and condenser motors.

1.5 Safety Devices

Details safety devices like pressure switches, circuit breakers, and fuses.

1.6 Air Conditioning Refrigeration Cycle

Explains the vapor compression system operation for cooling.

1.7 Heating Cycle

Describes the heating circuit operation using engine coolant.

SECTION 2 OPERATION (MANUAL CONTROLLER)

2.1 Starting, Stopping, and Operating Instructions

Procedures for starting, stopping, and operating the unit via manual controls.

2.2 Pre-Trip Inspection

Checks to perform after starting the system to ensure proper operation.

2.3 Modes of Operation

Details various operational modes like Cooling, Heating, and Vent.

2.3.1 Temperature Control

How to control interior temperature using the control knob.

2.3.2 Cooling Mode Operation

Describes the sequence of operations for the cooling mode.

2.3.3 Heating Mode Operation

Explains how the heating mode functions using engine coolant.

2.3.4 Boost Pump (Optional)

Function of the optional boost pump in heating mode.

2.3.5 Vent Mode Operation

Describes the unit's operation in vent mode when temperature is satisfied.

2.3.6 Compressor Unloader Control

How unloaders manage compressor capacity for temperature control.

2.3.7 Override Mode - AC310 (Dehumidification)

Enables dehumidification by running cooling circuits with heating.

2.4 Sequence of Operation (280P / 282P)

Step-by-step operational sequence for the 280P/282P thermostat.

2.4.1 Electronic Thermostat Sequence

Detailed sequence of operations triggered by the electronic thermostat.

SECTION 3 OPERATION BT324 CONTROLLER

3.1 Starting, Stopping, and Operating Instructions

Procedures for operating the unit using the BT324 controller.

3.2 Pre-Trip Inspection

Checks required after starting the system for BT324 controller operation.

3.3 Sequence of Operation BT324 CSDD

Outlines the operational sequence for the BT324 CSDD controller.

3.3.1 Function of Keys when "Engine On"

Explains key functions when the engine is running and controller is active.

3.3.2 Illuminating Indications (Display)

Describes what the illuminated indicators on the BT324 display signify.

3.4 Operating Instructions BT324

Detailed operating instructions for the BT324 controller.

3.4.1 Display Information

Explains what the BT324 display shows during operation.

3.4.2 Interior Temperature Control

How to adjust interior temperature settings using the BT324.

3.4.3 Ventilation Control

Information on ventilation speed control with the BT324.

3.4.4 Reheat Function

How to activate and use the optional Reheat mode for humidity control.

3.4.5 Temperature Indication

How to display inside and outside temperatures on the BT324.

3.5 Changing Between Fahrenheit and Celsius

Procedure to switch temperature units on the BT324 controller.

SECTION 4 TROUBLESHOOTING

4.1 System Will Not Cool

Identifies causes and checks for a system that fails to cool.

4.2 System Runs But Has Insufficient Cooling

Addresses issues causing reduced cooling performance.

4.3 Abnormal Pressures

Troubleshooting steps for abnormal system pressures.

4.4 Abnormal Noise Or Vibrations

Diagnosing and resolving unusual noises or vibrations.

4.5 No Evaporator Air Flow Or Restricted Air Flow

Troubleshooting airflow problems related to the evaporator.

4.6 Expansion Valve Malfunction

Identifying and resolving issues with the expansion valve.

4.7 Heating Malfunction

Troubleshooting common heating system failures.

SECTION 5 SERVICE

5.1 Maintenance Schedule

Recommended schedule for daily, weekly, and monthly maintenance tasks.

5.2 Removing Evaporator Cover

Steps for safely removing the evaporator section cover.

5.3 Removing Condenser Cover

Steps for safely removing the condenser section cover.

5.4 Installing Manifold Gauge Set

Guide for connecting a manifold gauge set for system servicing.

5.4.1 Installing R-134a Manifold Gauge/Hose SET

Procedure for preparing and installing the R-134a manifold gauge set.

5.5 Pumping The System Down or Removing Refrigerant Charge

Procedures for system pump down and refrigerant removal.

5.5.1 System Pump Down For Low Side Repair

Steps to pump down the system for low-side repairs.

5.5.2 Removing Entire System Charge

Method for completely removing the refrigerant charge.

5.6 Refrigerant Leak Check

Procedure for checking the refrigeration system for leaks.

5.7 Evacuation and Dehydration

Steps for evacuating and dehydrating the system.

5.7.1 General Procedures

General guidelines for system evacuation and dehydration.

5.7.2 Preparation for Evacuation

Necessary preparations before performing evacuation.

5.7.3 Evacuation and Dehydrating System Procedure

Detailed steps for evacuating and dehydrating the system.

5.8 Adding Refrigerant to System

Guidance on adding refrigerant to the system.

5.8.1 Checking Refrigerant Charge

How to accurately check the system's refrigerant charge.

5.8.2 Adding Full Charge

Procedure for adding the correct amount of refrigerant.

5.9 Checking for Noncondensibles

Method to check for non-condensable gases in the system.

5.10 Checking and Replacing High or Low-Pressure Cutout Switch

Procedures for servicing pressure cutout switches.

5.10.1 Replacing High or Low Pressure Switches

Steps for replacing defective pressure switches.

5.10.2 Checking High or Low Pressure Switches

How to check the functionality of pressure switches.

5.11 Filter-Drier Service

Information on servicing the filter-drier component.

5.11.1 To Check Filter-Drier

How to check if the filter-drier is restricted or needs replacement.

5.11.2 To Replace Filter-Drier Assembly

Steps for replacing the filter-drier assembly.

5.12 Servicing the Heat Valve

Maintenance and troubleshooting for the heat valve.

5.12.1 Coil Replacement

Procedure for replacing the heat valve coil.

5.12.2 Internal Part Replacement

Steps for replacing internal components of the heat valve.

5.12.3 Replace Entire Valve

How to replace the entire heat valve assembly.

5.13 Servicing the Liquid Line Solenoid Valve

Maintenance and troubleshooting for the liquid line solenoid valve.

5.13.1 Coil Replacement

Procedure for replacing the liquid line solenoid valve coil.

5.13.2 Internal Part Replacement

Steps for replacing internal components of the solenoid valve.

5.13.3 Replace Entire Valve

How to replace the entire liquid line solenoid valve.

5.14 Service Valves

Information on the function and use of service valves.

5.15 Replacing Return Air Filters

Steps for removing and replacing the vehicle's return air filters.

5.16 Thermostatic Expansion Valve

Information on the thermostatic expansion valve.

5.16.1 Valve Replacement

Procedure for replacing the thermostatic expansion valve.

5.16.2 Superheat Measurement

How to measure and interpret superheat readings.

SECTION 6 ELECTRICAL

6.1 Introduction

Overview of electrical wiring schematics for AC310/AC350 units.