Carrier 50FK, JK034-074, 48FK specifications Controls Operation and Troubleshooting

48FK,JK034-074 50FK,FY,JK,JY034-104 Variable-Air Volume Rooftop Units

Controls Operation,

and Troubleshooting

CONTENTS

Page

SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . 2

GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

Rooftop Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

VAV Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Processor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

·P1 Ð SUPPLY-AIR SET POINT

·P2 Ð ECONOMIZER POSITION

·P3 Ð RESET LIMIT

·P4 Ð DEMAND LIMIT

·P5 Ð ECONOMIZER MINIMUM POSITION

·P6 Ð WARM-UP SET POINT

·P7 Ð SASP RESET TEMPERATURE

·PROCESSOR BOARD OUTPUTS

·CONFIGURATION HEADER AND DIP SWITCH

ASSEMBLY

Relay Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Display Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Thermistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

·T1 Ð SUPPLY-AIR TEMPERATURE THERMISTOR

·T2 Ð RETURN-AIR TEMPERATURE THERMISTOR

·T3 Ð SATURATED CONDENSING TEMPERATURE, CIRCUIT 1

·T4 Ð SATURATED CONDENSING TEMPERATURE, CIRCUIT 2

·T10 Ð RESET TEMPERATURE

Compressor Operation . . . . . . . . . . . . . . . . . . . . . . . . . 7

·CONTROL RELAY (CR)

Accessory Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

·P3 Ð RESET LIMIT

·P5 Ð ECONOMIZER MINIMUM POSITION

·P6 Ð 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 Con®guration 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

Manufacturer reserves the right to discontinue, or change at any time, speci®cations or designs without notice and without incurring obligations.

Book	1	1	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
Tab	1a	1b