Controls Operation and Troubleshooting
48FK,JK034-074 50FK,FY,JK,JY034-104 Variable-Air Volume Rooftop Units
GENERAL
CONTENTS cont
SAFETY CONSIDERATIONS
Fig. 1 Ð Processor Board
Table 1 Ð Pin Terminal Connector J1 Thermistor Inputs
Return-Air Temperature
Fig. 3 Ð Pin Terminal Connector J2
Status Switch Inputs
Fig. 2 Ð Pin Terminal Connector J1 Thermistor Inputs
Table 2 Ð Pin Terminal Connector J2 Status Switch Inputs
The potentiometer locations and functions are as follows
Table 3 Ð Output Pin and Terminal Assignments
Fig. 5 Ð Relay Board
Compressor Operation
Fig. 8 Ð Thermistor T1 Location, 50FK,JK034-048 Units
GAS SECTION
HORIZONTAL SUPPLY SECTION
48FK,JK ONLY
Fig. 9 Ð Thermistor T1 Location, 48FK,JK, 50JY and
50JKX,JKY 054-074 Units and 50FKX,FKY and 50FY054-104 Units
Fig. 10 Ð Thermistor T1 Location, 50FK,JK054-074 Units
GAS SECTION
Fig. 11 Ð Thermistor T2 Location, Size 034-048 Units
Fig. 12 Ð Thermistor T2 Location, Size 054-104 Units
Fig. 13 Ð Thermistor T3 and T4 Locations Size 034-048 Units
STANDARD
Fig. 14 Ð Thermistor T3 and T4 Locations, Size 054-104 Units
054 UNITS 064, 074, 078 UNITS 088, 104 UNITS
Fig. 15 Ð Accessory Relay Board Standard Factory Supplied
Fig. 16 Ð Two-Step Demand Limit Module
Fig. 17 Ð Enthalpy Sensor Location
Fig. 18 Ð Variable Frequency Drive Sizes 034-048 and
CONTROLS INSTALLATION
Space Temperature Reset
Fig. 20 Ð Unit Control Box Arrangement, Sizes
Fig. 21 Ð Unit Control Box Arrangement, Sizes
Fig. 22 Ð Unit Control Box Arrangement, Sizes 088 and
Fig. 23 Ð Occupied/Unoccupied Switch with Night Setback Thermostat
Fig. 25 Ð Accessory Reset Board
Voltage Drop Characteristics
Fig. 24 Ð Heat Interlock Relay
Fig. 26 Ð Space Temperature Sensor Averaging
Fig. 29 Ð 115-Volt Field Wiring to Accessory
Fig. 27 Ð Single-Step Demand Limit
Fig. 28 Ð Two-Step Demand Limit Module
2-Step Demand Limit Control Module
This emulation requires the following eld-supplied parts
Fig. 30 Ð Remote SASP Wiring
Fig. 31 Ð External Alarm Indication
P Ð Manual Potentiometer R Ð Fixed Resistor Field Wiring
R Ð Resistor Factory Installed Factory Wiring Field Wiring
Table 6 Ð Smoke Control Switches Required for Each Mode
Modulating Power
Table 5 Ð Smoke Control Modes
Fire
Table 7 Ð Switch Functions
Modulating Power Exhaust
Table 8 Ð Tubing Size
SIZE in
ALL UNITS
Fig. 32 Ð Smoke Control Wiring
034-048 UNITS
Fig. 33 Ð Modulating Power Exhaust and Inlet
Guide Vane Differential Pressure Switch Sizes
Pressure Switch and Variable Frequency Drive
Fig. 35 Ð Modulating Power Exhaust Differential Pressure Switch Sizes
Table 11 Ð Conguration Header Jumpers
Table 10 Ð Conguration Header and DIP Switch Factory Settings
Table 9 Ð Potentiometer Inputs and Ranges
Table 12 Ð DIP Switches
Fig. 36 Ð Inlet Guide Vane Motor 50FK,JK034-074 Units
Fig. 37 Ð Inlet Guide Vane Motor, 48FK,JK, 50FY,JY
and 50FJX,FJY,FKX,FKY034-074 Units Fig. 38 Ð Inlet Guide Vane Motor
Size 078-104 Units
READ STOP WRITE RESET
Fig. 39 Ð Differential Pressure Switch for Inlet Guide
Modulating Power Exhaust Option
Fig. 41 Ð Jumper Removal to Disable Motor
Table 14 Ð Changing the VFD Set Point Frequency Command
Modulating Power Exhaust Option or Acces
Table 13 Ð VFD Set Point Frequency Command for Duct Pressure
START UNIT
Table 15 Ð Quick Test, Unit Conguration and Switch Check
CONTROL SWITCH
QUICK
NORMAL
Table 16 Ð Quick Test, Thermistor and Potentiometer Check
Table 17 Ð Quick Test, Output Relay Check
OPERATING INFORMATION
Table 18 Ð Sensor Resistance Values
warm-up routine, and a 26 will be displayed
044 AND 048 UNITS
Fig. 42 Ð Component Arrangement, 034-048 Units
034 AND 038 UNITS
Fig. 43 Ð Component Arrangement, 054-104 Units
054, 064 UNITS
074, 078 UNITS
088, 104 UNITS 104 UNITS
Supply Fan Control with IGV Ð In most VAV units, the supply fan static pressure is controlled by inlet guide vanes. The inlet guide vanes operate independently from the micro- processor. The supply static pressure is controlled by a dif- ferential pressure switch. If the unit is equipped with a re- turn fan, building pressure is controlled by another differential pressure switch
Fig. 44 Ð Modulating Power Exhaust Component Locations Sizes
Fig. 45 Ð Modulating Power Exhaust Component Locations Sizes
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Table 19 Ð Compressor Loading and Unloading Sequences
Table 19 Ð Compressor Loading and Unloading Sequences cont
Table 21 Ð Operation Status Codes
TROUBLESHOOTING
Table 20 Ð Controls Troubleshooting
Table 22 Ð Diagnostic Codes
· Wiring Problem Ð If the circuit is open, a failure will be detected
82 to be displayed on display board when display button is
will be energized and an error code of 82 will be displayed
ergize alarm light and cause an error code of 83 to be dis
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Fig. 48 Ð Processor Board Test Points
Fig. 49 Ð Relay Board Test Points
Table 23 Ð Voltage Reading
Fig. 50 Ð Relay Board Pin Terminal Connector J9
Fig. 51 Ð Display Board Pin Terminal Connector J10
Table 24 Ð Pin Terminal Connector J1 Voltages
Table 25 Ð Pin Terminal Connector J2 Voltages
Step 1 Ð Low-voltage relay resistance check
Step 2 Ð High-voltage relay resistance check
Table 27 Ð Terminal Strip J5 Connector Resistance Reading
Table 28 Ð Enthalpy Sensor Checkout
Variable Frequency Drive
Fig. 52 Ð Damper Motor Connection Diagram VAV
1. Disconnect all power to the unit and the VFD
Table 29 Ð Carrier Default Program Parameter Values
Frequency Settings
Gr.Fb
Gr.SF
Table 30 Ð Required User Adjusted Defaults
Table 31 Ð Motor Overload Settings
Fig. 53 Ð Variable Frequency Drive Terminal Block Size 034-048 Units
Fig. 54 Ð Variable Frequency Drive Terminal Block Size 054-104 Units
LEGEND AND NOTES FOR FIG
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SERVICE TRAINING
CALL FOR FREE CATALOG
START-UP CHECKLIST
II. PRELIMINARY CHECKLIST ITEMS
CONTROL SETTINGS
I. PRE-START-UP
TEMPERATURES
III. START-UP
IV. NOTES
ELECTRICAL
