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Controls Operation,
and Troubleshooting
CONTENTS
Page
SAFETY CONSIDERATIONS .....................2
GENERAL ...................................2-13
Rooftop Information ............................2
VAV Control System ...........................2
Processor Board ..............................2
• P1 — SUPPLY-AIR SET POINT
• P2 — ECONOMIZER POSITION
• P3 — RESET LIMIT
• P4 — DEMAND LIMIT
• P5 — ECONOMIZER MINIMUM POSITION
• P6 — WARM-UP SET POINT
• P7 — SASP RESET TEMPERATURE
• PROCESSOR BOARD OUTPUTS
• CONFIGURATION HEADER AND DIP SWITCH
ASSEMBLY
Relay Board
..................................5
Display Board .................................5
Thermistors ...................................5
• T1 — SUPPLY-AIR TEMPERATURE THERMISTOR
• T2 — RETURN-AIR TEMPERATURE THERMISTOR
• T3 — SATURATED CONDENSING TEMPERATURE,
CIRCUIT 1
• T4 — SATURATED CONDENSING TEMPERATURE,
CIRCUIT 2
• T10 — RESET TEMPERATURE
Compressor Operation
.........................7
• CONTROL RELAY (CR)
Accessory Board
..............................7
• P3 — RESET LIMIT
• P5 — ECONOMIZER MINIMUM POSITION
• P6 — MORNING WARM-UP TEMPERATURE
Single-Step Demand Unit
.......................7
Demand Limit Control Module (DLCM) ............7
Economizer ..................................10
• ENTHALPY CONTROL
• DIFFERENTIAL ENTHALPY
Variable Frequency Drive (VFD)
.................12
Temperature Reset ............................12
CONTROLS INSTALLATION ...................13-25
Control Wiring ...............................13
• NIGHT SETBACK THERMOSTAT
• SPACE TEMPERATURE RESET ACCESSORY
(50DJ900021)
Space Temperature Reset
......................13
• INSTALLATION
• CONFIGURATION
• OPERATING SEQUENCE
Demand Limit
................................18
• SINGLE-STEP DEMAND LIMIT
• TWO-STEP DEMAND LIMIT
• INSTALLATION
• CONFIGURATION
• OPERATING SEQUENCE
Control From Remote Building Management
System (BMS)
..............................19
• OCCUPIED/UNOCCUPIED
Page
• NIGHT SETBACK CONTROL
• UNIT SUPPLY AIR SET POINT ADJUSTMENT
• DEMAND UNIT (1-STAGE OR 2-STAGE)
• SUPPLY DUCT PRESSURE SET POINT ADJUSTMENT
• EXTERNAL ALARM SIGNAL
• REMOTE ECONOMIZER CONTROL
Smoke Control Modes
.........................21
• FIRE SHUTDOWN MODE
• PRESSURIZATION MODE
• EVACUATION MODE
• SMOKE PURGE MODE
• INSTALLATION
• CONFIGURATION
• OPERATING SEQUENCE
Air Pressure Tubing
...........................23
• INLET GUIDE VANES
• VARIABLE FREQUENCY DRIVE
• MODULATING POWER EXHAUST
START-UP
.................................25-30
Initial Check .................................25
Configuration Header .........................26
DIP Switches .................................26
Adjusting Set Points ..........................27
Potentiometers ...............................27
Supply Fan Control with IGV Option .............28
Supply Fan Control with VFD Option ............28
Modulating Power Exhaust
(Option or Accessory) .......................30
START UNIT ................................31-34
Quick Test Program ...........................31
OPERATING INFORMATION ...................34-43
Digital Display ...............................34
•
CODES 0 THROUGH 8, CAPACITY STEPS
• CODES 20 THROUGH 30 AND 88, OPERATIONAL
STATUS
• CODES 51 THROUGH 87, DIAGNOSTIC
INFORMATION
Operating Sequence
..........................35
• SIZE 034, 038 AND 048-088 UNITS
• SIZE 044 UNITS
• SIZE 104 UNITS
Head Pressure Control
........................36
Supply Fan Control with IGV ...................38
Supply Fan Control with VFD ...................38
Modulating Power Exhaust (Option or
Accessory Except FY,JY Units) ...............38
Unit Staging .................................38
TROUBLESHOOTING ........................44-57
Checking Display Codes .......................44
Complete Unit Stoppage .......................44
Single Circuit Stoppage .......................44
Restart Procedure ............................44
Diagnostic Codes .............................45
•
CODES 51, 52, 55, 56: COMPRESSOR FAILURE
48FK,JK034-074
50FK,FY,JK,JY034-104
Variable-Air Volume Rooftop Units
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 1
Tab 1a 1b
PC 111 Catalog No. 534-716 Printed in U.S.A. Form 48/50F,J-1T Pg 1 4-99 Replaces: 48/50D,F,J-1T