Contents
Main
Controls Operation, and Troubleshooting
CONTENTS
48FK,JK034-104 48FM078-104 50FK,FY,JK,JY034-104 50FM,FS078-104 Variable-Air Volume Rooftop Units
CONTENTS (cont)
SAFETY CONSIDERATIONS
GENERAL
Rooftop Information
VAV Control System
Processor Board
Fig. 1 Processor Board
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Relay Board
Display Board
Thermistors
Table 3 Output Pin and Terminal Assignments
Fig. 5 Relay Board
Compressor Operation
Accessory Board
Single-Step Demand Limit
Demand Limit Control Module (DLCM)
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Economizer
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Supply Fan Variable Frequency Drive (VFD)
High Capacity Modulating Power Exhaust Variable Frequency Drive (48FM and 50FM,FS Units Only)
Temperature Reset
CONTROLS INSTALLATION
Control Wiring
Space Temperature Reset
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Demand Limit
Control From Remote Building Management System (BMS)
[(P3 SASP) X(0.6 F) X (TR R@13.3) ]
Smoke Control Modes
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Air Pressure Tubing
034-048 UNITS
Fig. 32 Smoke Control Wiring
054-104 UNITS
48FK, JK AND 50FK, JK034-104 UNITS
48FM, AND 50FM, FS034-104 UNITS
START-UP Initial Check
Configuration Header
DIP Switches
Adjusting Set Points
Potentiometers
Supply Fan Control with IGV Option
Supply Fan Control with VFD Option
STOP RESET
RUN
READ WRITE
Modulating Power Exhaust (Option or Acces- sory) (48FK,JK and 50FK,JK Units) The Mod-
High Capacity Power Exhaust (48FM and 50FM,FS Units) The power exhaust VFD will modu-
START UNIT
Quick Test Program Turn on power to unit.
Table 16 Quick Test, Unit Configuration and Switch Check
Table 17 Quick Test, Thermistor and Potentiometer Check
Table 18 Quick Test, Output Relay Check
OPERATING INFORMATION Digital Display The VAV control system uses a 2-digit
Operating Sequence The sequence presented be-
Head Pressure Control All units have as standard a
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Supply Fan Control with IGV In most VAV units,
Supply Fan Control with VFD When equipped
Modulating Power Exhaust (48FK,JK and 50FK,JK Units Option or Accessory) The pow-
High Capacity Modulating Power Exhaust (48FM and 50 FM,FS Units) The high-capacity
Unit Staging Compressor loading and unloading se-
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Table 20 Compressor Loading and Unloading Sequences
Fig. 48 Modulating Power Exhaust Return End Sheet Metal Skin Detail; 48FM and 50FM,FS Units
Table 20 Compressor Loading and Unloading Sequences (cont)
TROUBLESHOOTING
Checking Display Codes To view the digital dis-
Complete Unit Stoppage If the unit is off, there are
Single Circuit Stoppage If a single circuit stops,
Restart Procedure Before attempting to restart the
Diagnostic Codes Diagnostic codes are warnings of
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Thermistor Troubleshooting The VAV con trol
Electronic Controls Checkout The following will
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Enthalpy Sensor Checkout To test operation of
Economizer Motor All control of the motor (i.e.,
Supply Fan Variable Frequency Drive
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Table 30 Carrier Default Program Parameter Values (Supply Fan VFD)
Power Exhaust Variable Frequency Drive (48FM and 50FM,FS)
Fig. 56 Variable Frequency Drive Terminal Block
Unit Wiring A typical wiring schematic is shown in
LEGEND AND NOTES FOR FIG. 57
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SERVICE TRAINING
START-UP CHECKLIST
I. PRE-START-UP:
II. PRELIMINARY CHECKLIST ITEMS:
III. START-UP
IV. NOTES
