Carrier 48HG014 Controls Operation And Troubleshooting

Contents

Carrier 48HG014 Controls Operation And Troubleshooting Manual pdf 1 page image

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.PC 111 Catalog No. 534-80090 Printed in U.S.A. Form 48/50HG-2T Pg 1 202 10-01 Replaces: 48/50HG-1TBook 1 1 4 4Tab 1a 1b 6a 6bControls Operation and TroubleshootingCONTENTSSAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . 1GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1MAJOR SYSTEM COMPONENTS . . . . . . . . . . . . . . .1-11General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Main Base Board (MBB) . . . . . . . . . . . . . . . . . . . . . . . . . . 1Economizer Control Board (ECB) . . . . . . . . . . . . . . . . 2Scrolling Marquee Display . . . . . . . . . . . . . . . . . . . . . . . 2Board Addresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Control Module Communication. . . . . . . . . . . . . . . . . . 2• RED LED• GREEN LED• YELLOW LEDCarrier Comfort Network Interface. . . . . . . . . . . . . . . . 2Field-Installed Accessories . . . . . . . . . . . . . . . . . . . . . . 2• SPACE TEMPERATURE SENSOR (T55)• SPACE TEMPERATURE SENSOR (T56)• SPACE TEMPERATURE SENSOR (T58)• SPACE TEMPERATURE SENSOR CALIBRATION• ECONOMIZER• POWER EXHAUST• INDOOR AIR QUALITY• SMOKE DETECTOR• FILTER STATUS• FAN STATUS• ENTHALPY SENSORSCONTROLS AND FUNCTIONS . . . . . . . . . . . . . . . . 11-25Marquee Display Usage . . . . . . . . . . . . . . . . . . . . . . . . . 11Clearing Unit Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Service Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-31Unit Control Type (U.CTL) . . . . . . . . . . . . . . . . . . . . . . . 26Occupancy Determination. . . . . . . . . . . . . . . . . . . . . . . 26Indoor Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Outdoor Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Economizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Indoor Air Quality (IAQ) . . . . . . . . . . . . . . . . . . . . . . . . . 27Power Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Compressor Staging . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Heating (48HG Units). . . . . . . . . . . . . . . . . . . . . . . . . . . . 28• THERMOSTAT CONTROL• SPACE SENSOR CONTROLHeating (50HG Units). . . . . . . . . . . . . . . . . . . . . . . . . . . . 29• THERMOSTAT CONTROL• SPACE SENSOR CONTROLCooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30• THERMOSTAT CONTROL• SPACE SENSOR CONTROLSpace Temperature Sensor Calibrationand Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Alarm Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . 31-39Complete Unit Stoppage . . . . . . . . . . . . . . . . . . . . . . . . 31Single Circuit Stoppage . . . . . . . . . . . . . . . . . . . . . . . . . 31Service Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Restart Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Alarms and Alerts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Page• DIAGNOSTIC ALARM CODES ANDPOSSIBLE CAUSESThermistor Troubleshooting. . . . . . . . . . . . . . . . . . . . . 39• THERMISTOR/TEMPERATURE SENSOR CHECKTransducer Troubleshooting . . . . . . . . . . . . . . . . . . . . 39START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39-43APPENDIX A — CCN TABLES . . . . . . . . . . . . . . . . 44-52CONTROL SET-UP CHECKLIST . . . . . . . . . .CL-1, CL-2SAFETY CONSIDERATIONSInstallation and servicing of air-conditioning equipment canbe hazardous due to system pressure and electrical compo-nents. Only trained and qualified service personnel shouldinstall, repair, or service air-conditioning equipment. Untrainedpersonnel can perform the basic maintenance functions ofreplacing filters. All other operations should be performed bytrained service personnel. When working on air-conditioningequipment, observe precautions in the literature, tags and labelsattached to the unit, and other safety precautions that mayapply. Follow all safety codes. Wear safety glasses and workgloves. Use quenching cloth for unbrazing operations. Havefire extinguishers available for all brazing operations.GENERALThis publication contains Start-Up, Controls, Operation,and Troubleshooting information for the 48/50HG rooftopunits. See Table 1. These units are equipped with ComfortLinkcontrols.Table 1 — Unit Sizes (48/50HG)MAJOR SYSTEM COMPONENTSGeneral — The 48/50HG single package rooftop units withelectric cooling and with gas heating (48HG units) or electriccooling and electric heating (50HG Units) contain theComfortLink electronic control system that monitors all opera-tions of the rooftop. The control system is composed of severalcomponents as listed in sections below. See Fig. 1-3 for thecontrol and power schematics. Figure 4 shows the layout of thecontrol box, unit, and thermistor and transducer locations.Main Base Board (MBB) — See Fig. 5. The MBB isthe center of the ComfortLink control system. It contains themajor portion of the operating software and controls the opera-tion of the unit. The MBB continuously monitors input/outputchannel information received from its inputs and from theEconomizer Control Board (ECB). The MBB receives inputsUNIT MODEL NOMINAL TONS48/50HG014 12 1 /248/50HG016 1548/50HG020 1848/50HG024 2048/50HG028 2548/50HG014-028Single Package Large Rooftop Unitswith ComfortLink™ Controls