Carrier 48AJ - Page 98

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Fig. 15 — Typical 2 Stage Gas Heat Wiring Schematic (Size 051 and 060 Units Shown)

A48-6866

Main Page

Table of Contents1
Service and Troubleshooting1
Safety Considerations2
General2
Basic Control Usage3
Comfortlink Control3
Scrolling Marquee3
Accessory Navigator™ Display4
Operation4
System Pilot™ Interface4
CCN Tables and Display5
- Generics Status Display Table5
Conventions Used in this Manual5
Start-Up7
Unit Preparation7
Unit Setup7
Internal Wiring7
Accessory Installation7
Crankcase Heaters7
Evaporator Fan7
Controls7
Gas Heat7
Controls Quick Start27
Two-Stage Constant Volume Units with27
- Mechanical Thermostat27
- Space Sensor27
Variable Air Volume Units Using Return Air Sensor or Space Temperature Sensor27
Multi-Stage Constant Volume Units with28
- Mechanical Thermostat28
- Space Sensor28
Economizer Options28
Indoor Air Quality Options28
Exhaust Options28
Set Clock on VFD (if Installed)28
Programming Operating Schedules29
Service Test29
General29
Service Test Mode Logic29
Independent Outputs30
Fans30
Cooling30
Heating30
Third Party Control30
Thermostat30
Alarm Output30
Remote Switch30
VFD Control31
Supply Air Reset31
Demand Limit Control31
Demand Controlled Ventilation Control31
Controls Operation32
Modes32
- System Modes32
- Hvac Modes33
Unit Configuration Submenu35
Cooling Control36
- Setting up the System37
- Machine Dependent Configurations37
- Set Points37
- Supply Air Reset Configuration38
- Cooling Configuration38
- Demand Limit Control45
- Economizer Integration with Mechanical Cooling47
Heating Control47
- Setting up the System47
- Heat Mode Selection Process48
- Temperature Driven Heat Mode Evaluation48
- Heat Mode Diagnostic Help49
- Integrated Gas Control Board Logic51
- Morning Warm up53
- Tempering Mode53
Static Pressure Control54
- Setting up the System54
- Static Pressure Reset56
- Related Points56
Fan Status Monitoring57
- Setting up the System57
- Supply Fan Status Monitoring Logic57
Dirty Filter Switch57
Economizer57
- Unoccupied Economizer Free Cooling59
- Economizer Operation Configuration59
- Economizer Diagnostic Help60
Building Pressure Control61
- Building Pressure Configuration61
- Constant Volume 2-Stage Control61
- Multiple Power Exhaust Stage Building61
- Pressure Control Operation61
Indoor Air Quality Control63
- Setting up the System64
- Pre-Occupancy Purge66
Smoke Control Modes63
- Fire-Smoke Inputs63
Dehumidification and Reheat66
- Setting up the System66
Temperature Compensated Start67
- Setting up the System67
- Temperature Compensated Start Logic68
Carrier Comfort Network (CCN)68
Alert Limit Configuration69
Sensor Trim Configuration69
Discrete Switch Logic Configuration70
Display Configuration71
Remote Control Switch Input71
Hot Gas Bypass72
Space Temperature Offset72
Time Clock Configuration72
Troubleshooting74
Complete Unit Stoppage74
Single Circuit Stoppage74
Service Analysis74
Restart Procedure74
Thermistor Troubleshooting74
Transducer Troubleshooting74
Forcing Inputs and Outputs83
Run Status Menu83
- Auto View of Run Status84
- Economizer Run Status84
- Cooling Information85
- Mode Trip Helper85
- Ccn/Linkage Display Table85
- Compressor Run Hours Display Table85
- Compressor Starts Display Table85
- Time Guard Display Table85
- Software Version Numbers Display Table85
Alarms and Alerts86
Major System Components94
General94
Factory-Installed Components94
Accessory Control Components114
Service118
Service Access118
Cleaning118
Lubrication120
Evaporator Fan Performance Adjustment120
Evaporator Fan Coupling Assembly120
Evaporator Fan Service and Replacement121
Belt Tension Adjustment121
Evaporator-Fan Motor Replacement121
Condenser-Fan Adjustment121
Four-Inch Filter Replacement121
Power Failure121
Refrigerant Charge121
Thermostatic Expansion Valve (TXV)122
Gas Valve Adjustment122
Main Burners122
Filter Drier122
Replacement Parts122
Appendix A - Local Display Tables123
Appendix B - Ccn Tables131
Appendix C - Vfd Information144
- Appendix D - Mode Selection152
- Process152
- Airflow Control During Fire-Smoke Modes154
Index154
Unit Start-Up Checklist159

Carrier 48AJ - Page 98

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