Carrier 25VNA User Manual

Service Manual
25VNA
Infinityt Variable Speed Heat Pump
with Greenspeedt Intellig ence
2to5NominalTons
TABLE OF CONTENTS
PAGE
UNIT IDENTIFICATION 2..................................................................................
SAFETY CONSIDERATIONS 3..............................................................................
GENERAL INFORMATION 3................................................................................
ELECTRICAL 4--6.........................................................................................
ELECTRONIC EXPANSION VALVE (EXV) 5--6.................................................................
Controller 5............................................................................................
Crankcase Heater 5......................................................................................
Outdoor Fan Motor 5.....................................................................................
Time--Delays 5.........................................................................................
Infinity Controlled Low Ambient Cooling 6...................................................................
Utility Interface with Infinity Control 6.......................................................................
COMMUNICATION AND STATUS FUNCTION LIGHTS 6--7......................................................
REFRIGERANT PIPING LENGTH LIMITATIONS 8.............................................................
LONG LINE APPLICATIONS 8--9............................................................................
TROUBLESHOOTING 10--30................................................................................
REFRIGERATION SYSTEM 33--37...........................................................................
Refrigerant 33..........................................................................................
Compressor Oil 33.......................................................................................
Servicing Systems on Roofs With Synthetic Materials 33.........................................................
Brazing 33.............................................................................................
Service Valves and Pump down 34--35.......................................................................
Liquid Line Filter Drier 36................................................................................
Suction Line Filter Drier 36................................................................................
Thermostatic Expansion Valve (TXV) 36.....................................................................
Accumulator 37.........................................................................................
REFRIGERATION SYSTEM REPAIR 38.......................................................................

Carrier 25VNA Specifications

General

Refrigerant	R-410A
Energy Star Certified	Yes
Stages	Variable
HSPF2	Up to 9.5
Compressor Type	Variable Speed
Cooling Capacity	2-5 tons
Heating Capacity	2-5 tons
Warranty	10-year parts limited warranty

Summary

SAFETY CONSIDERATIONS

ELECTRICAL AND CUT HAZARDS

Outlines electrical shock, high voltage, and cut hazards with precautions.

UNIT OPERATION AND REFRIGERANT HAZARDS

Covers hazards related to unit operation, refrigerant pressure, and fan blades.

ADVANCED SYSTEM FEATURES

LOW AMBIENT COOLING LOGIC

DEFROST CYCLE MANAGEMENT

TROUBLESHOOTING AND FAULT CODES

SYSTEM COMMUNICATION AND MODEL PLUG ISSUES

PRESSURE SWITCH AND THERMISTOR FAULTS

Describes responses to pressure switches and common thermistor errors.

FAULT CODE LIST (TABLE 5)

Lists fault codes, flash codes, and reset times for system events.

25VNA EVENT/FAULT TABLE

DETAILED EVENT/FAULT DESCRIPTIONS

Lists system events/faults, causes, and recommended actions.

TEMPERATURE SENSOR TROUBLESHOOTING

SCROLL TEMPERATURE DIAGNOSTICS

Flowcharts for diagnosing scroll temperature faults.

MOTOR TEMPERATURE DIAGNOSTICS

Flowcharts for diagnosing motor temperature faults.

VARIABLE SPEED DRIVE (VSD) DIAGNOSTICS

DRIVE COMMUNICATION AND VOLTAGE CHECKS

REFRIGERATION SYSTEM SERVICE

REFRIGERANT, OIL, AND BRAZING PROCEDURES

Covers refrigerant handling, compressor oil, and brazing procedures.

SERVICE VALVES, PUMPDOWN, AND EVACUATION

Details service valve functions and refrigerant isolation procedures.

REFRIGERATION SYSTEM REPAIR

LEAK DETECTION METHODS