HVAC Service Technicians Training Center48-03 32nd Place, Long Island City, NY 11101 Tel: (718) 472-0404 (718) 472-0414 Fax: (718) 433-0676

Introduction to the Refrigeration Cycle: Part 2 (AC/R-2)This course is a continuation of Part 1 I Intro. To Refrigeration Cycle, focusing on high temperatureapplications including: compressors, condensers, evaporators, metering devices, accessory components,compressor capacity controls, balanced system operation, and pressure-temperature charts.

DAY 1SUBJECT: Introduction to the Troubleshooting Chart and System Operating ComponentsGOAL: Demonstrate how an entire air condition system is affected by a single problem

and how it can be diagnosed by the troubleshooting chart. Show how the TXVand Cap react to over charge and under charge.

OBJECTIVES: Understand the terminology on the troubleshooting char and terminology used inthe HVAC/R trade.Use the chart to diagnose problems in a typical A/C systemWhat happen to each component under these conditionsNote differences between charging valves and the service valve

SUBJECT CONTENTS:Troubleshooting chart instructionsTerminology used on the chartTemp changes across an air cool condenserTemp changes across a DX fan coilNormal pressure ranges in an A/C systemSub cooling tempSuperheat tempTerminology used on componentsTXV, captubesSafety when installing & removing service gaugesIdentify different types of refrigerant valves and the useUse of different thermometersReview of shop safety

METHODS/TECHNIQUES: Handout on troubleshooting chart

Refrigeration & A/C Technology W.J.T.RESOURCES: Large troubleshooting chart

Ref trainerOverheadSystem room

EVALUATION: Entrance ExamGive superheat reading for given problemGive subcool reading for given problemGet temperature difference across the air evaporatorGet temperature difference across air cooler condenser

DAY 2SUBJECT: The Troubleshooting Chart And System Operating Components Pressure

Relief DevicesGOAL: Demonstrate how system performance is affected by poor air flow and to use

dye.OBJECTIVES: To use troubleshooting chart to diagnose different mechanical problems

Understand that troubleshooting chart is a tool for learning to diagnose A/Csystem problems

To take correct temperature & pressure measurementsTo identify different pressure relief devices and how they workHow pressure reliefs are piped in a refrigeration system and why they areneeded

SUBJECT CONTENTS:HVAC/R industry termsRelief devices externalFusible plugSpring loadedSafety reason for relief valvesSolving A/C problems using chart

METHODS/TECHNIQUES: Refrigeration & A/C Technology W.J.T.

Troubleshooting chartsOverheadsSystem room

RESOURCES: Refrigeration & A/C technology W.J.T.Troubleshooting handoutsSporlan TXVAlco TXVHenry valve

EVALUATION: HomeworkQuizSolving A/C problem using large troubleshooting chart in front of classShop able to get superheat

able to get evap air diff. tempable to get cond. air . diff. temp.

DAY 3SUBJECT: Refrigeration Operating Temperatures And Defrost SystemsGOAL: To identify different refrigeration equipment and temperature ranges.

Demonstrate setting up of low pressure temperature control and the operation ofdifferent defrost controls

OBJECTIVES: Student will be able to:Define refrigeration temperature ranges

a) AC high temperatureb) Medium temperaturec) Low temperature

Identify equipmenta) Low boy boxb) Reach in boxc) Walk in boxd) Ice machinee) Heat pump

Discuss/note typical temperatures of evaporators coil temperature todischarge air temperature

a) Control of temperatureb) Adjusting of low pressure controlc) Fin spacing of different coils

Discuss/note different types of defrost: off cycle, radin, planea) Electb) Hot Gc) Start of defrost clockd) Control of evaporator fane) Termination defrostf) Clock

g) Temperatureh) Pressure

Understand the function of defrosta) Ice meltingb) Returning oil to the compressorc) Use on a heat pump

SUBJECT CONTENTS:Trade languageTemperature rangesSetting of low pressure switcherSetting of defrost controls

METHODS/TECHNIQUES: Classroom handout

Refrigeration & A/C Technology W.J.T.System room set up of low pressure control

RESOURCES: Work book/handoutsRefrigeration & A/C Technology W.J.T.PT. Char Dupont, sporlan or alco

EVALUATION: HomeworkQuizShop performance set up of pressure control

DAY 4SUBJECT: EPR Control Devices, Refrigerant Migration Protection.

Troubleshooting ChartGOAL: To understand the EPR valve and how it works with the TXV. To identify the 3

types of refrigerant migration protection strategy and draw an electrical wiringdiagram for each.

OBJECTIVES: Student will be able to:Distinguish between mechanical controlsExplain how an EPR valve functionsDescribe electrical controls that apply to refrigerant migration protectionDiscuss how poor air or water flow affected a system differently than adirty condenserDraw wiring diagram of 3 types of refrigeration migration protection

SUBJECT CONTENTS:Trade termsEPR control diagrams & installation instructionReview of TXV operation

METHODS/TECHNIQUES: Refrigeration & A/C Technology W.J.T.

Work book handoutsOverheadsLarge troubleshooting chart

RESOURCES: Refrigeration & A/C Technology W.J.T.SporlanAlcoHenryAscoDupont product information

EVALUATION: Shop show system with pump downDemonstrate location of EPR valve installationDemonstrate location of LL Solenoid installation & make wiring diagramQuiz

DAY 5SUBJECT: Recovery, Evacuation and Leak CheckingGOAL: Demonstrate the use of recovery equipment, vacuum pump & leak checking.

OBJECTIVES: Student will be able to:Understand the proper procedure to evacuate a refrigeration system

a) Use of the micron gauge (scale)b) Best line sizec) Heat lamps

Connect a recovery machinea) Push pullb) Vapor recover

Demonstrate how to leak check:a) Standing pressure testb) Electronicc) Halide leakd) Dye visible & U.V.e) Sound ultra sonic

SUBJECT CONTENTS:Trade (terms) languageSafety precaution when using gauge manifoldRobinair vacuum instructionsRobinair recovery instructionsHazards of working with halide torch leak detector

METHODS/TECHNIQUES:

Refrigeration & A/C Technology W.J.T.Work book handoutsOverheads

RESOURCES: Refrigeration & A/C Technology W.J.T.Manufacture Instruction & Direction

a) Vacuum pumpb) Recovery

EVALUATION: HomeworkQuizShop (PBF)

DAY 6SUBJECT: Refrigerant Oils And Safety ControlsGOAL: Demonstrate how an oil pressure works and how it is connected to a

compressor. Also how to take net oil pressure on compressors.OBJECTIVES: Student will be able to:

Understand the purpose for refrigerant oil & typesUnderstand net oil pressure readingDemonstrate how an oil pressure safety switch is wired in a circuitExplain the function of an oil pressure switch

SUBJECT CONTENTS:Trade (terms) languageSafety use of tools & equipmentInstallation and testing of an oil pressure safetyOperation of an oil pressure safety switch

METHODS/TECHNIQUES: Refrigeration & A/C Technology W.J.T.

Work book handoutsOverheads

RESOURCES: Refrigeration & A/C Technology W.J.T.Penn - Johnson

EVALUATION: PBFQuiz - writtenHomework

DAYS 7 & 8SUBJECT: Auxiliary Components Their Applications and Operation in the Refrigeration

CircuitGOAL: To identify by shape & location on refrigeration piping the different components &

their functions.OBJECTIVES: Student will be able to point out location for component installation & lines

connected to component and its purpose.a) Liquid line drier & size itb) Capillary strainer - drierc) Suction accumulator and with heat exchangerd) Mufflers suction & dischargee) Receiversf) Desuperheatiing heat exchangerg) Subcooling heat exchangerh) Oil separatori) Oil reservoirsj) Sight glassesk) Vibrationl) EPR valvem) CPR valven) Relief valve, plug & disko) Head pressure control

Fun Cycle Fan speed Air volume

p) Flooding condenser controls, oroa valveq) Solenoid valver) Pressure switcher

Low pressure safety Low pressure control High pressure switch Low ambient control Oil safety switch

SUBJECT CONTENTS:Trade names of componentsTrade terms used (language)Troubleshooting chart; when components are usedDanger when using torch or system with compressed refrigerants

METHODS/TECHNIQUES: Refrigeration & A/C Technology W.J.T.

Work book handoutsOverheads

RESOURCES: Refrigeration & A/C Technology W.J.T.Refrigeration Research Inc.AlcoSporlanRancoPenn JohnsonLarge Troubleshooting Chart

EVALUATION: HomeworkQuiz

DAY 9SUBJECT: Cooling Towers; Water Supplies & Water Reg ValveGOAL: Demonstrate simple maintenance service on tower, back flush a condenser and

adjust a water valveOBJECTIVES: Student will be able to:

Discuss/understand the operation of a cooling towerIdentify different types of towers

a) Forced Airb) Natural Draft

Discuss the water supply & treatment for cooling towerIdentify safety conditions when working on indoor & outdoor towersDiscuss adjusting/flushing water valve

SUBJECT CONTENTS:Trade language (terms)Poor safety attitudeThe effect of electrical shockDanger of flooding spaceFreeze up

METHODS/TECHNIQUES: Work book handouts

OverheadsPBF in system room

RESOURCES: Marley towerMetreyPenn - Johnson

EVALUATION: HomeworkQuizPBF

DAY 10SUBJECT: Evaporative Condensers, Evaporative Fluid Cooler and DrycoolersGOAL: To understand different type of head rejection devices operation temperature and

use in winter operationOBJECTIVES: Student will be able to:

Identify & define an evaporative condenser, an evaporative fluid and adrycoolerDiscuss temperature drop across eachDiscuss winter operation, types of sump heaters, fan cycle controls

SUBJECT CONTENTS:Trade (terms) languageTaking temperatureCheck performancesVenting linesSafety with electrical around water

METHODS/TECHNIQUES: Work book handouts

OverheadsLarge troubleshooting charts

RESOURCES: MarleyEDPACBACMammoth Inc.North American Heat TransferHeat Craft

EVALUATION: HomeworkQuiz

DAYS 11 & 12SUBJECT: Using Troubleshooting Chart to Find Component ProblemsGOAL: To be able to diagnose problems where chart leaves off by reason & logicOBJECTIVES: Student will be able to:

Solve refrigerant service calls

Check components mechanical & electricalDiagnose multiple problems

SUBJECT CONTENTS:Dealing with customers poor attitudesService Industry term & languageCare in taking pressure & temperature readingSafety on ladders & electric shockRules for diagnosingProblem to solve

METHODS/TECHNIQUES: Refrigeration & A/C Technology W.J.T.

Large troubleshooting chartWork bookService callsSystem room role playing

RESOURCES: Refrigeration & A/C Technology W.J.T.EVALUATION: Quiz

HomeworkPBFSolving Service Problems