Carrier WeatherMaster 50HCQA04, Service And Maintenance Instructions, Page: 1 / 98

50HCQ*04---12
Single Package Heat Pump/Electric Heat
Nominal 3 to 10 Tons
With Puron (R---410A) Refrigerant
Service and Maintenance Instructions
TABLE OF CONTENTS
SAFETY CONSIDERATIONS 1 . . . . . . . . . . . . . . . . . . . .
UNIT ARRANGEMENT AND ACCESS 3 . . . . . . . . . . .
RETURN AIR FILTERS 3 . . . . . . . . . . . . . . . . . . . . . . . . .
SUPPLY FAN (BLOWER) SECTION 4 . . . . . . . . . . . . . .
HEAT PUMP REFRIGERATION SYSTEM 9 . . . . . . . . .
PURON

(R--410A) REFRIGERANT 12 . . . . . . . . . . . . .
THERMOSTATIC EXPANSION VALVE (TXV) 13 . . . .
COOLING CHARGING CHARTS 16 . . . . . . . . . . . . . . . .
CONVENIENCE OUTLETS 22 . . . . . . . . . . . . . . . . . . . .
HEAT PUMP CONTROLS 23 . . . . . . . . . . . . . . . . . . . . . .
PROTECTIVE CONTROLS 23 . . . . . . . . . . . . . . . . . . . . .
COMMERCIAL DEFROST CONTROL 24 . . . . . . . . . . .
ELECTRIC HEATERS 27 . . . . . . . . . . . . . . . . . . . . . . . . .
SMOKE DETECTORS 30 . . . . . . . . . . . . . . . . . . . . . . . . .
PREMIERLINK

CONTROL 37 . . . . . . . . . . . . . . . . . . .
RTU--OPEN CONTROL SYSTEM 38 . . . . . . . . . . . . . . . .
SENSORY/ACCESSORY INSTALLATION 38 . . . . . . . .
ADDITIONAL RTU--OPEN INSTALLATION AND
TROUBLESHOOTING 38 . . . . . . . . . . . . . . . . . . . . . . . . .
PRE--START--UP START-UP 40 . . . . . . . . . . . . . . . . . . . .
START-UP, GENERAL 40 . . . . . . . . . . . . . . . . . . . . . . . .
START-UP, PREMIERLINK

42 . . . . . . . . . . . . . . . . . . .
START-UP, RTU--OPEN 42 . . . . . . . . . . . . . . . . . . . . . . .
FASTENER TORQUE VALUES 43 . . . . . . . . . . . . . . . . .
APPENDIX I. MODEL NUMBER SIGNIFICANCE 44 . . .
APPENDIX II. PHYSICAL DATA 46 . . . . . . . . . . . . . . . .
APPENDIX III. FAN PERFORMANCE 52 . . . . . . . . . . .
APPENDIX IV. ELECTRICAL INFORMATION 62 . . . .
APPENDIX V. WIRING DIAGRAMS 87 . . . . . . . . . . . . .
APPENDIX VI. MOTORMASTER SENSOR
LOCATIONS 105 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UNIT START-UP CHECKLIST 109 . . . . . . . . . . . . . . . . .
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment
can be hazardous due to system pressure and electrical
components. Only trained and qualified service personnel
should install, repair, or service air-conditioning
equipment. Untrained personnel can perform only the
basic maintenance functions such as replacing filters.
Trained service personnel should perform all other service
and maintenance operations.
When working on air-conditioning equipment, observe
precautions in the literature, tags and labels attached to
the unit, and other safety precautions that can apply.
Follow all safety codes. Wear approved safety glasses and
leather work gloves. Use quenching cloth for unbrazing
operations. Have fire extinguishers available for all
brazing operations.
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 see this symbol on the unit and in
instructions or manuals, be aware of the potential 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
avoided, could result in minor to moderate injury or
product and property damage.
NOTICE
is used to address
practices not related to physical injury. NOTE is used to
highlight suggestions which
will
result in enhanced
installation, reliability, or operation.