Page 1: Table Of Contents
CODES 51, 52, 55, 56: COMPRESSOR FAILURE Printed in U.S.A. Form 48/50F,J-1T 48FK,JK034-074 50FK,FY,JK,JY034-104 ......21 .
Page 2: Safety Considerations
GENERAL Page IMPORTANT: This literature contains controls, operation, and troubleshooting data for 48FK,JK and 50FK,FY,JK,JY variable air volume rooftop units. Use this guide in conjunction with the separate Installation Instructions literature packaged with the unit.
Page 3 LEGEND — Dual In-Line Package EPROM — Erasable, Programmable Read-Only Memory — Electronic Expansion Valve Do not remove label covering EPROM. Removal causes pro- gram to be erased. Several temperature inputs are connected to the proces- sor. There are either 4 or 5 thermistors (depending on the ﬁeld-installed accessories) which input temperature data into the processor through pin terminal connector J1.
Page 4 LEGEND — Thermistor Field Wiring Accessory Fig. 2 — Pin Terminal Connector J1 Thermistor Inputs Table 2 — Pin Terminal Connector J2 Status Switch Inputs CONNECTOR J2 STATUS SWITCH TERMINAL NO. Oil Pressure, Circuit 2 Oil Pressure, Circuit 1 Loss Of Charge, Circuit 2 Loss of Charge, 9,10...
Page 5: P3 - Reset Limit
The potentiometer locations and functions are as follows: P1 — SUPPLY-AIR SET POINT — This potentiometer is located on the display board. The supply-air set point is the cooling mode control temperature which the VAV control system will attempt to maintain at Thermistor T1 by con- trol of economizer position and/or cycling unloaders and compressors.
Page 6 Table 3 — Output Pin and Terminal Assignments OUTPUT PIN- TERMINAL Stage 1 J6-1 Compressor Relay (K1)* Stage 2 J6-2 Compressor Relay (K2)* Stage 3 J6-3 Compressor Relay (K3)* Stage 4 J6-4 Compressor Relay (K4)† Stage 5 J6-5 Compressor Relay (K5)† Stage 6 J6-6 Compressor Relay (K6)†...
Page 7: Compressor Operation
P1 SUPPLY AIR TWO-DIGIT SET POINT DISPLAY POTENTIOMETER Fig. 6 — Display/Set Point Board Compressor Operation CONTROL RELAY (CR) — This relay provides informa- tion to the processor about compressor operation (one con- trol relay per compressor). The relay controls and protects the compressor and also controls the crankcase heater.
Page 8 GAS SECTION HORIZONTAL SUPPLY SECTION (48FK,JK ONLY) (50FY,JY ONLY) AND EXTENDED PLENUM SECTION (50FKX,FKY,JKX,JKY) Fig. 7 — Thermistor T1 Location, 48FK,JK, 50FY,JY and 50FKX,FKY,JKX,JKY 034-048 Units FAN DISCHARGE/ELECTRIC HEAT SECTION Fig. 8 — Thermistor T1 Location, 50FK,JK034-048 Units...
Page 9 GAS SECTION HORIZONTAL DISCHARGE SECTION (50FY,JY) (48FK,JK) AND EXTENDED PLENUM SECTION (50FKX,FKY,JKX,JKY) Fig. 9 — Thermistor T1 Location, 48FK,JK, 50JY and 50JKX,JKY 054-074 Units and 50FKX,FKY and 50FY054-104 Units FAN DISCHARGE/ELECTRIC HEAT SECTION Fig. 10 — Thermistor T1 Location, 50FK,JK054-074 Units...
Page 10: Economizer
STANDARD FILTERS Fig. 11 — Thermistor T2 Location, Size 034-048 Units STANDARD FILTERS Fig. 12 — Thermistor T2 Location, Size 054-104 Units Economizer — Economizer control is used to control the outside and return air dampers of the unit, to satisfy space cooling demand using all outside air (when permitted), and to satisfy cooling in conjunction with compressor operation (when conditions permit).
Page 11 054 UNITS 064, 074, 078 UNITS 088, 104 UNITS Fig. 14 — Thermistor T3 and T4 Locations, Size 054-104 Units...
Page 12: Variable Frequency Drive (Vfd)
LEGEND ECON — Economizer — Minimum — Potentiometer — Variable-Air Volume Fig. 15 — Accessory Relay Board (Standard; Factory Supplied) LEGEND — Integrated Circuit — Input — Potentiometer RTN — Return Fig. 16 — Two-Step Demand Limit Module Fig. 17 — Enthalpy Sensor Location Variable Frequency Drive (VFD) —...
Page 13: Controls Installation
Fig. 25. If multiple sensors are required to average the space tem- perature, see Fig. 26. Use only Carrier Part Number HH79NZ014 sensor, in arrangements of 4 or 9 sensors, with total wiring not to exceed 1000 ft.
Page 17 034-048: TB3 054-104: TB4 OCCUPIED/UNOCCUPIED SWITCH NIGHT SETBACK THERMOSTAT NOTES: 1. Occ/Unocc switch closes when occupied. 2. Night setback thermostat closes when in night setback heating. Fig. 23 — Occupied/Unoccupied Switch with Night Setback Thermostat 034-048: TB3 054-104: TB4 N.O. N.C.
Page 18: Installation Configuration Operating Sequence Demand Limit
SIZES 034-048 TO ACCESSORY SPACE TEMPERATURE RESET CONTROL BOARD SIZES 054-104 SENSOR 1 SPACE TEMPERATURE RESET — 4 SENSOR AVERAGING APPLICATION SIZES 034-048 TO ACCESSORY SPACE TEMPERATURE RESET CONTROL BOARD SIZES 054-104 NOTE: Sensor part number is HH79NZ014. SPACE TEMPERATURE RESET — 9 SENSOR AVERAGING APPLICATION Fig.
Page 19: Operating Sequence
Connect the potentiometer end terminals to terminals 8 and 9 on control terminal block TB3 (sizes 034-048) or TB4 (sizes 054-104) (see Fig 27). Connect the switch terminals to the potentiometer wiper arm terminal and to terminal 10 on TB3 or TB4. To enable demand limit function, change DIP switch 5 to position ON.
Page 20 VFDs that permit direct communication between the VFD and several BMS communication sys- tems. Contact your Carrier representative for information on selecting an appropriate accessory interface board and the name of the local service office (for sale and installation of the accessory boards).
Page 21: Smoke Control Modes
EXTERNAL ALARM SIGNAL — The unit controls pro- vide an external alarm status signal via a 115-vac output sig- nal at the relay board J5, available at TB2-4 and TB2-5 (common). This signal can be forwarded to the BMS by add- ing a signal relay at the alarm output, placing its coil across terminals TB2-4 and TB2-5 and using its contacts to control a discrete input to the BMS (see Fig.
Page 22: Pressurization Mode
INSTALLATION — To enable one or more of the possible smoke control modes available with these units, determine the switches required for the desired mode(s) from Table 6, ﬁeld-supply and install the appropriate switches and ﬁeld wire per Fig. 32. Switch functions are shown in Table 7. Table 5 —...
Page 23: Air Pressure Tubing
SWITCH CONFIGURATION NUMBER SW-1 N.C. SW-2 N.C. SW-3 N.O. SW-4 N.O. SW-5 N.C. SW-6 N.O. SW-7 N.O. SW-8 N.C. A: N.O. SW-9A/B B: N.C. LEGEND — Building Pressure DPS — Differential Pressure Switch EOR — Economizer Open Relay — Heat Interlock Relay —...
Page 24 034-048 UNITS SW-1 REMOVE JUMPER SW-2 REMOVE JUMPER SW-3 SW-4 SW-5 REMOVE JUMPER SW-6 SW-9A SW-9B REMOVED FROM TB3-7 REMOVED FROM C-DPS LEGEND DPS — Differential Pressure Switch — Heat Interlock Relay — Switch — Terminal Block ALL UNITS SW-7 SW-8 Fig.
Page 25: Start-Up
Fig. 33 — Modulating Power Exhaust and Inlet Guide Vane Differential Pressure Switch (Sizes 034-048) Fig. 34 — Inlet Guide Vane Differential Pressure Switch and Variable Frequency Drive Duct Pressure Transducer (Sizes 054-104) Fig. 35 — Modulating Power Exhaust Differential Pressure Switch (Sizes 054-104) MODULATING POWER EXHAUST —...
Page 26: Conﬁguration Header
Table 9 — Potentiometer Inputs and Ranges POTENTIOMETER DESCRIPTION Supply Air Set Point Economizer Position Reset Limit Demand Limit, P4† Single-Step DLCM-P1 Demand Limit, 2-Step DLCM-P2 Minimum Economizer Position Warm-Up Set Point Reset P7** Temperature *Optional factory-installed economizer is required. Potentiometer P2 is not a set point. †Accessory two-step demand limit module is required (which has 2 potentiometers), or a 5 to 20 k-ohm ﬁeld-supplied potentiometer is required for single-step demand limit.
Page 27: Adjusting Set Points
OFF. Conﬁrm setting per Table 10. Change only if in error. DIP SWITCH NO. 4 — Morning Warm-Up. For 48FK,JK models, this switch will be ON (morning warm-up enabled). For 50FK,JK units with factory-installed electric heaters, this switch will be ON.
Page 28: Supply Fan Control With Igv Option
Its lo- cation is not shown in this ﬁgure. Fig. 37 — Inlet Guide Vane Motor, 48FK,JK, 50FY,JY, and 50FJX,FJY,FKX,FKY034-074 Units Fig. 38 — Inlet Guide Vane Motor,...
Page 29 Troubleshooting, Vari- STOP able Frequency Drive section (page 52). RESET IMPORTANT: The Carrier factory default values for the VFD may be different than the default values of the manufacturer. Refer to the Service section when checking default values.
Page 30: Modulating Power Exhaust (Option Or Accessory)
Table 13 — VFD Set Point (Frequency Command) for Duct Pressure PRESSURE VFD SET POINT (Hz) (in. wg) 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 Table 14 — Changing the VFD Set Point (Frequency Command)* KEY OPERATION LED MESSAGE XX.X or OFF 60.0 45.0 (ﬂashing)
Page 31: Start Unit
START UNIT To start unit: 1. Close the unit-mounted ON/OFF switch (located in the main control box). 2. Close the ﬁeld-supplied and -installed timeclock (or con- trol) switch (contacts located at Terminals 1 and 2 (TB3 for 034-048, TB4 for 054-104). IMPORTANT: The ﬁeld-supplied and installed switch (or timeclock) MUST BE CLOSED to put unit in Occupied mode.
Page 32 Table 15 — Quick Test, Unit Conﬁguration and Switch Check QUICK NORMAL TEST DISPLAY STEP NO. 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1 1.0. 1.1. 1.2. 1.3. LEGEND DIP — Dual, In-Line Package —...
Page 33 Table 16 — Quick Test, Thermistor and Potentiometer Check QUICK NORMAL TEST DISPLAY STEP NO. 1 — Thermistor OK 1.4. 0 — Thermistor Faulty 1 — Thermistor OK 1.5. 0 — Thermistor Faulty 1 — Thermistor OK 1.6. 0 — Thermistor Faulty 1 —...
Page 34: Operating Information
Table 18 — Sensor Resistance Values TEMP RESISTANCE TEMP RESISTANCE (Ohms) (Ohms) −60 362,640 11,396 −55 297,140 9,950 −50 245,245 8,709 −45 202,841 7,642 −40 168,250 6,749 −35 139,960 5,944 −30 116,820 5,249 −25 98,420 4,644 −20 82,665 4,134 −15 69,685 3,671 −10...
Page 35: Operating Sequence
Operating Sequence — The sequence presented be- low assumes that the unit is equipped with heat for morning warm-up and an economizer. If these items are not enabled with the appropriate DIP switches, the processor bypasses these subroutines. This sequence is also based on an EPROM (erasable, programmable, read-only memory) processor chip with the identiﬁcation ‘HT204485-1-XX,’...
Page 36: Head Pressure Control
SIZE 044 UNITS — These units have 2 compressors and 1 unloader on compressor no. 1. See Fig. 42 for compressor and condenser fan motor locations. The unit operating se- quence is as follows: Stage 1 Relays K1 and K3 are energized. Compressor no.
Page 37 054, 064 UNITS 054-088 UNITS 074, 078 UNITS 088, 104 UNITS 104 UNITS Fig. 43 — Component Arrangement, 054-104 Units...
Page 38: Supply Fan Control With Igv
Supply Fan Control with IGV — 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.
Page 39 Fig. 44 — Modulating Power Exhaust Component Locations; Sizes 034-048...
Page 41 Fig. 46 — Modulating Power Exhaust Return End Sheet Metal Skin Detail; Sizes 034-048 Fig. 47 — Modulating Power Exhaust Return End Sheet Metal Skin Detail; Sizes 054-104...
Page 42 Table 19 — Compressor Loading and Unloading Sequences COOLING Lead Circuit STAGE Unloader Comp 1 COOLING Lead Circuit STAGE Unloader Comp 1 COOLING Lead Circuit STAGE Comp 1 COOLING Lead Circuit STAGE Unloader Comp 1 SIZE 034 UNITS Lag Circuit Unloader Comp 2 SIZE 038 UNITS...
Page 43 Table 19 — Compressor Loading and Unloading Sequences (cont) COOLING Lead Circuit STAGE Comp 1 Unloader U1 COOLING Lead Circuit STAGE Comp 1 Unloader U1 COOLING Lead Circuit STAGE Comp 1 Unloader U1 COOLING Lead Circuit STAGE Comp 1 Unloader U1 COOLING Lead Circuit STAGE...
Page 44: Troubleshooting
TROUBLESHOOTING By using the display module, actual operating conditions of the unit are displayed while it is running. The Quick Test function allows proper operation of compressors, compres- sor unloaders, fans, and other components to be checked while unit is stopped. If an operating fault is detected, an alarm is generated and an alarm code(s) is displayed.
Page 45: Diagnostic Codes
Diagnostic Codes — Diagnostic codes are warnings of abnormal or fault conditions, and may cause either one circuit or the whole unit to shut down. They are assigned code numbers as described below. Table 22 contains a description of each diagnostic code error and possible cause.
Page 46 CODES 59 AND 60: LOW-PRESSURE SWITCH — These codes are used to indicate a low-pressure switch failure. The processor monitors the low-pressure switch. If the switch opens, either by low refrigerant charge, circuit failure, or wir- ing error, the circuit is locked off. Code 59 indicates a failure of the lead circuit, and as a result, that circuit will be shut down.
Page 47 10 Kohm, 3-wire linear potentiometer and an accessory 2-step control are available from Carrier. The single-step control has a single potentiometer while 2-step control has 2 potentiometers (mounted on the demand limit board, see Fig. 26).
Page 48 These 2 steps will help determine if a component other than a board is at fault or if the problem is external to control circuit. A volt-ohmmeter will be needed to troubleshoot boards. A digital meter is preferred but a Simpson 260 or equivalent will work.
Page 49 Step 5 — Check Relay Board Outputs from the Processor Board — This step involves checking the output signals from relays K1-K3 on the relay board. 1. Turn power to OFF position. 2. Connect negative test probe to TP19 (meter still set to dc).
Page 50 Table 24 — Pin Terminal Connector J1 Voltages TERMINAL (vdc ± 0.25 v) Step 9 − Thermistor Input Connector Checkout 1. Turn power to OFF position. 2. Disconnect all plugs for pin terminal connector J2 and mark them for later replacement. 3.
Page 51 Table 27 — Terminal Strip J5 Connector Resistance Reading J5 PIN NUMBERS QUICK TEST STEP NO. 1. to 2.5. 2.7. 2.8. 2.9. to 3.3. LEGEND — Inﬁnity Step 2 — Check the Display LEDs 1. Enter Quick Test mode. 2. If is not displayed, replace display board.
Page 52 Carrier equipment. Some speciﬁcations and control conﬁguration defaults for Carrier applications will differ from the VFD manufacturer manual included in the packet. See Table 29 for listing of Carrier-speciﬁc de- fault values. STANDARD TRANSDUCER CONTROL — The VFD moni- tors and controls duct pressure (DP) via a differential pres- sure transducer.
Page 53 Gr.Pr (Protection) Gr.Ut (Utility) *These settings differ from the Toshiba defaults and are required for Carrier applications. NOTE: To restore original factory settings, change tYP to 6 in Setup mode (SetP). This restores the VFD original factory settings. PARAMETER ACC1...
Page 54 Occasionally it may be necessary to restore the VFD de- faults to the general Carrier use values. These are stored in an OPTION ROM (read-only memory chip). However, some variables may need to be manually changed to match the speciﬁc unit’s factory default settings.
Page 55 LEGEND AND NOTES FOR FIG. 55 — Alarm — Contactor — Circuit Breaker — Control Circuit Breaker COMP — Compressor — Crankcase Heater — Control Relay — Differential Pressure Switch — Discharge Pressure Transducer — Enering-Air Temperature — Enthalpy Control —...
Page 58 Course descriptions and schedules are in our catalog. CALL FOR FREE CATALOG 1-800-962-9212 [ ] Packaged Service Training Copyright 1999 Carrier Corporation Manufacturer reserves the right to discontinue, or change at any time, speciﬁcations or designs without notice and without incurring obligations. Book 1 1 PC 111 Catalog No.
Page 59 VERIFY THAT POWER SUPPLY MATCHES UNIT DATA PLATE VERIFY THAT ALL ELECTRICAL CONNECTIONS AND TERMINALS ARE TIGHT CHECK GAS PIPING FOR LEAKS (48FK,JK ONLY) CHECK THAT INDOOR-AIR FILTERS ARE CLEAN AND IN PLACE CHECK FAN WHEEL AND PROPELLER FOR LOCATION IN HOUSING/ORIFICE, AND VERIFY SET SCREWS...
Page 60 VERIFY REFRIGERANT CHARGE USING CHARGING CHARTS IN UNIT INSTALLATION INSTRUCTIONS GENERAL ECONOMIZER MINIMUM VENT SETTING TO JOB REQUIREMENTS IV. NOTES Copyright 1999 Carrier Corporation Manufacturer reserves the right to discontinue, or change at any time, speciﬁcations or designs without notice and without incurring obligations. Book 1 1 PC 111 Catalog No.

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