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48FK,JK034-074
50FK,FY,JK,JY034-104
Variable-Air Volume Rooftop Units
Controls Operation,
and Troubleshooting
CONTENTS
Page Page
• NIGHT SETBACK CONTROL
SAFETY CONSIDERATIONS .....................2
• UNIT SUPPLYAIR SET POINTADJUSTMENT
GENERAL...................................2-13
• DEMAND UNIT (1-STAGE OR 2-STAGE)
Rooftop Information............................2
• SUPPLY DUCT PRESSURE SET POINTADJUSTMENT
VAV Control System ...........................2
• EXTERNALALARM SIGNAL
Processor Board ....
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CONTENTS (cont) GENERAL Page IMPORTANT: This literature contains controls, • CODES 59AND 60: LOW-PRESSURE SWITCH operation, and troubleshooting data for 48FK,JK and • CODES 63AND 64: OIL PRESSURE SWITCH 50FK,FY,JK,JYvariableairvolumerooftopunits.Use • CODE 70: ILLEGAL UNIT CONFIGURATION thisguideinconjunctionwiththeseparateInstallation • CODES 71 TO 76: THERMISTOR/RESISTOR Instructions literature packaged with the unit. FAILURE • CODE 81: RESET THERMISTOR OR Carrier 48FK,JK and 50FK,FY,JK,JY uni
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LEGEND *EPROM HT204485-1-XX where ‘‘XX’’ is the current revision number. DIP — Dual In-Line Package EPROM — Erasable, Programmable Read-Only Memory NOTE: Processor Board is positioned in unit with J3 and J10 con- EXV — Electronic Expansion Valve nections at the bottom. Do not remove label covering EPROM. Removal causes pro- gram to be erased. Fig. 1 — Processor Board Several temperature inputs are connected to the proces- In addition to the unit status switch inputs, the processor sor. There are
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LEGEND CR — Control Relay EC — Enthalpy Control LEGEND LPS — Low-Pressure Switch T— Thermistor Field Wiring Fig. 3 — Pin Terminal Connector J2 Accessory Status Switch Inputs Fig. 2 — Pin Terminal Connector J1 Thermistor Inputs Table 2 — Pin Terminal Connector J2 Status Switch Inputs CONNECTOR J2 UNIT SIZE STATUS SWITCH TERMINAL NO. 034-104 Oil Pressure, 1,2 Jumpered Circuit 2 Oil Pressure, 3,4 Jumpered Circuit 1 Loss Of Charge, 7,8 LPS2 Circuit 2 Loss of Charge, 9,10 LPS1 Circuit 1 Economizer 13
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Thepotentiometerlocationsandfunctionsareasfollows: The configuration header (part no. 30GB660001) is a series of 8 small wires that are broken or unbroken in a P1 — SUPPLY-AIR SET POINT — This potentiometer is patterntoindicateseveraluniquecharacteristicsoftheunit. located on the display board.The supply-air set point is the The configuration header is factory set and should not be cooling mode control temperature which the VAV control changed.Changingthefactorysettingmaycausetheunitto system will
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Table 3 — Output Pin and Terminal Assignments OUTPUT PIN- NAME RATING DEVICE TERMINAL Stage 1 J6-1 CR1 Compressor Relay (K1)* Stage 2 J6-2 U2** Compressor Relay (K2)* Stage 3 J6-3 U1 Compressor Relay (K3)* Stage 4 J6-4 Not Used 24 vac Compressor Relay (K4)† Stage 5 J6-5 CR2 Compressor Relay (K5)† Stage 6 J6-6 Not Used Compressor Relay (K6)† J6-7 Economizer Open Relay (K7) EOR J6-8 Economizer Close Relay (K8) ECR J5-1 Supply Fan Relay (K9) IFC J5-2 Morning Warm-Up Relay (K10) HIR Stage 1 Condense
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P3—RESETLIMIT—Theprocessorboardisprogrammed P1 SUPPLY AIR TWO-DIGIT DISPLAY SET POINT DISPLAY BUTTON for occupied space temperature reset. In order for reset to POTENTIOMETER work, the accessory temperature reset board must be used. Potentiometer P3 is the maximum set point temperature to which the supply air can be reset. P5—ECONOMIZERMINIMUMPOSITION—Thispo- tentiometer controls the set point for the minimum position of the economizer. P6—MORNINGWARM-UPTEMPERATURE—Thispo- tentiometer controls t
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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 8
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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 9
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STANDARD BAG FILTERS FILTERS Fig.11—ThermistorT2Location,Size034-048Units Fig. 13 — Thermistor T3 and T4 Locations, Size 034-048 Units ENTHALPYCONTROL—Outsideairenthalpycontrolis standard with the factory-installed economizer option. En- thalpy is sensed by a controller located behind the end out- side air hood.The control can be accessed by removing the upper hood filter. See Fig. 17. DIFFERENTIALENTHALPY—Addedefficienciesinecono- mizer control can be gained by installing a differential en- thal
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054 UNITS 064, 074, 078 UNITS 088, 104 UNITS Fig. 14 — Thermistor T3 and T4 Locations, Size 054-104 Units 11
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Variable Frequency Drive (VFD) — The optional VFDisusedtomodulatesupplyfanairflowtomaintainduct static pressure on VAV applications. The VFD is located in the supply fan section (see Fig. 18 and 19), and can be ac- cessed by opening the fan section access door. Theunitissuppliedwithapressuretransducercapableof measuring from 0.0 to 5.0 in. wg. The pressure transducer will senda4to20mAsignal to the VFD to modulate the speedoftheindoorfanmotortopreciselycontrolthefanto the desired static pressure s
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capacity stages to maintain user-established supply-air set There are no required 115-volt field wiring connections, point temperature. When VAV units are also equipped with therefore no provisions have been made in the unit for run- optionalsupplyductpressurecontrols(eitherinletguidevanes ning115-voltwiring.Ifanyofthefield-installedoptionsre- [IGV]orvariablefrequencydrivepackage),theunitalsosenses quiring 115-volt connections are desired, the unit must be an increase in duct static pressure and r
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14 Fig. 20 — Unit Control Box Arrangement, Sizes 034-048
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15 Fig. 21 — Unit Control Box Arrangement, Sizes 054-078
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16 Fig. 22 — Unit Control Box Arrangement, Sizes 088 and 104
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034-048: TB3 034-048: TB3 Controlwillautomaticallyadjustleavingairtemperatureby 054-104: TB4 054-104: TB4 the following formula: MSP = SP + [(P3 - SP) / 3] x (P7 − T10) 12 where: MSP = Modified Leaving-Air Set Point OCCUPIED/UNOCCUPIED SP = Supply-Air Set Point SWITCH P3 = Maximum Supply-Air Temperature (reset limit) P7 = Reset Initiation Temperature (reset set point) NIGHT SETBACK THERMOSTAT T10 = Actual Space Temperature 3 = Ratio for reset (F) (fixed parameter) Table 4 — Thermistor Resistan
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RED RED BLK BLK SIZES 034-048 TB3 RED RED RED 12 BLK BLK BLK 15 TO ACCESSORY SPACE TEMPERATURE RESET CONTROL BOARD SIZES 054-104 TB4 12 15 SENSOR 1 SENSOR 2 SENSOR 3 SENSOR 4 SPACE TEMPERATURE RESET — 4 SENSORAVERAGINGAPPLICATION SIZES 034-048 TB3 RED RED RED 12 BLK BLK BLK 15 TO ACCESSORY SPACE TEMPERATURE RESET CONTROL BOARD SENSOR 1 SENSOR 3 SENSOR 2 SIZES 054-104 TB4 12 RED RED 15 BLK BLK SENSOR 4 SENSOR 5 SENSOR 6 NOTE:SensorpartnumberisHH79NZ014. RED RED BLK BLK SENSOR 7 SENSOR 8 SENSOR 9
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Connect the potentiometer end terminals to terminals 8 034-048: TB3 054-104: TB4 and9oncontrolterminalblockTB3(sizes034-048)orTB4 (sizes 054-104) (see Fig 27). Connect the switch terminals 8 to the potentiometer wiper arm terminal and to terminal 10 on TB3 or TB4. Toenabledemandlimitfunction,changeDIPswitch5to positionON.(DisconnectcontrolpowerbeforechangingDIP 5-20K 9 switchpositions.Reconnectpowerafterallchangeshavebeen POTENTIOMETER (P4) made.) SetthepotentiometerP4todesiredcapacityreductio
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OCCUPIED/UNOCCUPIED—Theunitcontrolsystemwill Configuration— Configure as follows: initiate normal occupied mode functions (including Morn- 1. Set DIP switch no. 2 to ON. ingWarm-up, Economizer Minimum Position, and Cooling 2. Adjust manual potentiometer to 12.6 to 12.8 k-ohm. Cycle)wheneveracontactclosureismadethatemulatesthe normaltimeclockcontacts.SeeFig.23.(‘‘Occupied/Unoccupied 3. ConfiguretransducerforjobsiteinputsignalfromBMS. Switch’’).ThecontactclosurefromtheBMSmustbeaniso- 4. AdjustPotenti
