50HC
Single P ackage Rooft op Electric Co oling Unit
wit h Puron (R---410A) Refr igerant
3 to 12. 5 Nominal Tons (Sizes 04---14)
Service and Maintenance Instructions
TABLE OF CONTENTS
SAFETY CONSIDERATIONS 1....................
UNIT ARRANGEMENT AND ACCESS 2...........
SUPPLY FAN (BLOWER) SECTION 4..............
STAGED AIR VOLUME CONTROL --2 SPEED FAN
WITH VARIABLE FREQUENCY DRIVE (VFD) 7....
ADDITIONAL VARIABLE FREQUENCY DRIVE
(VFD) INSTALLATION AND TROUBLESHOOTING. 8
MOTOR 8......................................
COOLING 12...................................
THERMOSTATIC EXPANSION VALVE (TXV) 14....
PURONR (R --410A) REFRIGERANT 15.............
COOLING CHARGING CHARTS 17................
COMPRESSOR 21...............................
CONVENIENCE OUTLETS 24....................
SMOKE DETECTORS 25.........................
SENSOR AND CONTROLLER TESTS 29...........
PROTECTIVE DEVICES 32.......................
PREMIERLINK CONTROL 33...................
RTU--OPEN CONTROL SYSTEM 33................
SENSORY/ACCESSORY INSTALLATION 34........
ADDITIONAL RTU--OPEN INSTALLATION AND
TROUBLESHOOTING 34.........................
ECONOMIZER UNITS 36........................
PRE-- START--UP/START--UP 44....................
START--UP, GENERAL 45........................
START--UP, PREMIERLINK CONTROLS 46.......
START--UP, RTU--OPEN CONTROLS 46............
FASTENER TORQUE VALUES 47.................
APPENDIX I. MODEL NUMBER SIGNIFICANCE 48.
APPENDIX II. PHYSICAL DATA 49................
APPENDIX III. FAN PERFORMANCE 52...........
APPENDIX IV WIRING DIAGRAMS 71............
APPENDIX V. MOTORMASTER SENSOR
LOCATIONS 121................................
UNIT START-UP CHECKLIST 124.................
SAFETY CONSIDERAT I ONS
Installation and servicing of air-conditioning equipme nt
can be hazardous due to system pressure and electrical
compone nts. Only trained and qualified service personnel
should install, repair, or service air-conditioning
equipment. Untrained personnel can perform the basic
maintenance functions of replacing filters. Trained service
personnel should perform al l other operations.
When working on a ir-conditioning equipment, observe
precautions in the literature, tags and labels attached to
the unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenc hing cloth for unbrazing operat ions.
Have fire extinguishers availabl e for all brazing and
unbrazing ope rations.
Read these instructions thoroughly and follow all
warnings or cautions attached to the unit. Consult local
building codes and National Electrical Code (NEC) for
special requirements.
Recognize safety information. This is the safety ALERT
symbol
. When you se e this symbol on the unit and i n
instructions or manuals, be aware of the potenti al for
physical injury hazards.
Understand the signal words DANGER, WARNING,and
CAUTION. These words are used with the safety--ALERT
symbol. DANGER indicates a hazardous situation which,
if not avoided, will result in death or severe personal
injury. WARNING indicates a hazardous situation which,
if not avoided, could result in death or personal injury.
CAUTION indicates a hazardous situation which, if not
avoide d, could result in minor to moderate injury or
product and property damage. NOTICE is used to address
practices not rela ted to physical injury. NOTE is used to
highlight suggestions which will result in enhanced
installation, reliability, or operation.
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