Department of Real Work
Prepare
KEY REVIEW TOPICS:
Your Phase 5 Final will evaluate your competency across the seven topics below. Review the knowledge, concepts, and hands-on skills you’ll be expected to demonstrate. Once you’re prepared to complete your Phase 5 Final, schedule time with a Master or Senior Technician and return to this Block to Complete Final.
1
Refrigerant Recovery
2
Nitrogen
Use & Testing
3
Vacuum Pump
& Evacuation
4
Refrigerant
Charging
5
Soldering
6
Brazing
7
Silver
Soldering
1
Refrigerant Recovery
Overview:
Refrigerant recovery requires the safe removal, handling, and documentation of refrigerant. Be prepared to properly set up the equipment, perform the recovery, and explain the decisions you make throughout the process.
Skills & Techniques:
-
Proper LOTO before recovery
-
Gauges, recovery machine, tank, and scale setup
-
Proper valve sequence and recovery procedure
-
Recovery tank pressure, capacity, and cooling
-
Refrigerant scale use and documentation
-
Filter drier and solenoid magnet use when required
Key Concepts:
-
Which refrigerants can and cannot be combined, and why
-
Recovery machine vs. vacuum pump applications
-
How temperature and pressure affect recovery
-
Required recovery endpoint and how to verify completion
-
EPA 608 responsibilities for recovery and refrigerant handling
2
Nitrogen
Use & Testing
Overview:
Nitrogen is used throughout refrigeration service for brazing and pressure testing. Be prepared to properly set up and use nitrogen for each application and explain why it is required.
Skills & Techniques:
-
Nitrogen tank, regulator, and hose setup
-
Proper purging/flowing of nitrogen during brazing
-
Proper low-pressure nitrogen flow during brazing
-
Nitrogen pressure test setup and procedure
-
Correct pressure and duration for pressure testing
-
Safe use of nitrogen regulators, tanks, and valves
Key Concepts:
-
When and why nitrogen is used during brazing
-
Purpose of purging/flowing nitrogen through the system
-
When nitrogen pressure testing is required
-
Purpose of a pressure test and what it can identify
-
Why nitrogen is used for pressure testing rather than other gases
3
Vacuum Pump
& Evacuation
Overview:
Proper evacuation prepares a refrigeration system for charging by removing air, moisture, and other non-condensables. Be prepared to correctly set up the equipment, pull an adequate vacuum, and verify the system is ready to proceed.
Skills & Techniques:
-
Gauges, vacuum pump, and vacuum gauge setup
-
Proper vacuum pump connection and operation
-
Correct procedure for pulling an adequate vacuum
-
Vacuum level measurement and verification
-
Determining when the system is ready for charging
Key Concepts:
-
Purpose of evacuating a refrigeration system before charging
-
Effects of non-condensables and moisture in the system
-
Required vacuum level before proceeding
-
Difference between a vacuum pump and recovery machine
-
How to determine whether an adequate vacuum has been achieved
4
Refrigerant Charging
Overview:
Proper refrigerant charging requires the correct refrigerant type, quantity, and charging procedure. Be prepared to set up the equipment, safely charge the system, and explain the decisions made throughout the process.
Skills & Techniques:
-
Gauges, refrigerant tank, and scale setup
-
Proper refrigerant charging procedure
-
Correct refrigerant type and charge quantity
-
Proper charging of blended refrigerants
-
Correct tank orientation and charging side
-
Tank heater setup and use when appropriate
Key Concepts:
-
When a system is ready for refrigerant charging
-
What must be completed before charging
-
Why blended refrigerants require specific charging procedures
-
Why refrigerant is charged through the appropriate side of the system
-
How tank temperature and pressure affect charging
-
Importance of measuring and documenting charge quantity
5
Soldering
Overview:
Proper soldering requires correct joint preparation, heat control, material selection, and safe technique. Be prepared to complete a clean, leak-free copper-to-copper joint and explain when soldering is the appropriate joining method.
Skills & Techniques:
-
Proper sanding, deburring, and cleaning of copper
-
Correct flux application
-
Proper torch flame, heat, and positioning
-
Copper-to-copper joint soldering
-
Proper solder application and technique
-
Inspection for joint quality, holes, and leaks
-
Safe torch and soldering practices
Key Concepts:
-
When and why soldering is appropriate
-
Approximate soldering temperature for copper
-
Correct solder type and silver content
-
Purpose and proper use of flux
-
Role of capillary action in forming the joint
-
Characteristics of a properly completed solder joint
6
Brazing
Overview:
Proper brazing requires joint preparation, heat control, material selection, and safe technique. Be prepared to braze a component into the system and produce a clean, leak-free joint.
Skills & Techniques:
-
Proper joint preparation and cleaning
-
Correct torch flame, heat, and positioning
-
Proper brazing rod application
-
Filter drier removal and installation
-
Inspection for joint quality and leaks
-
Safe brazing practices
Key Concepts:
-
When and why brazing is appropriate
-
Approximate brazing temperature
-
Brazing rod composition and proper selection
-
Importance of nitrogen flow during brazing
-
Protecting components from excessive heat
-
Characteristics of a properly brazed joint
7
Silver Soldering
Overview:
Silver soldering requires proper heat control, material selection, and safe technique. Be prepared to install a component using silver solder and produce a clean, leak-free joint.
Skills & Techniques:
-
Proper joint preparation and cleaning
-
Correct torch flame, heat, and positioning
-
Proper silver solder application
-
Filter fitting installation
-
Inspection for joint quality and leaks
-
Safe soldering practices
Key Concepts:
-
When and why silver soldering is appropriate
-
Approximate silver soldering temperature
-
Proper silver solder selection and use
-
Protecting components from excessive heat
-
Characteristics of a properly completed joint