REFRIGERATION FUNDAMENTALS

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REFRIGERATION FUNDAMENTALS

• HVAC/R

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SOLDERING BRAZING

• When and why
• When an A/C or refrigeration system is entered,
  it must be properly sealed
• Although flared fittings are widely used, most
  components are joined by soldering and brazing

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SOLDERING BRAZING

• Difference between soldering and brazing
• Soldering is accomplished with temps under 800F
• Brazing is accomplished with temps over 800F
  usually 1,000F to 1,500F

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SOLDERING BRAZING

• SOLDERING
• Soldering is an adhesion process
• Solder flows into tubing pores
• Joining takes place when solder hardens
• Solder has low tinsel strength
• It is not recommended for A/C or refrigeration
  systems due to the high temps and high pressures

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SOLDERING BRAZING

• SOLDERING
• Soldering is an adhesion process
• Solder flows into tubing pores
• Joining takes place when solder hardens
• Solder has low tinsel strength
• It is not recommended for A/C or refrigeration
  systems due to the high temps and high pressures

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SOLDERING BRAZING

• Newer solder gives tinsel strength of braze and
  lower melting point of solder
• Known as silver bearing solder
• StayBright 6 and StayBright 8
• Both contain silver

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SOLDERING BRAZING

• When soldering, flux must be used
• Most common is Solderine
• Proper cleaning, fluxing, assembly support, and
  heating is necessary
• 1) Clean all surfaces to be soldered
• 2) use clean flux on all ends
• 3) Do not overheat
• 4) Have parts properly supported

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SOLDERING BRAZING

• The solder has a lower melting point than the
  copper being joined
• Solder should be distributed evenly around and in
  the joint
• Heat the joint evenly, tube and fitting
• As flux clears, apply heat directly to the joint

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SOLDERING BRAZING

• Capillary action will take place, leaving a
  proper fillet or cap
• No globs or drips should be present
• Clean joint with a cloth

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SOLDERING BRAZING

• BRAZING
• Brazing is a common practice in HVAC/R
• On large applications, oxy-acetylene is used
• Most day to day operations can be done with a
  plumbers torch and acetylene
• Brazing is a welding practice

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SOLDERING BRAZING

• Unlike soldering, brazing can be done to join 2
  dissimilar metals
• Many different alloys or filler metals are
  available for HVAC/R work
• Most common
• 5 Silver
• 15 Silver
• 45 Silver

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SOLDERING BRAZING

• The greater the silver content, the greater the
  tinsel strength
• 5 and 15 are sold by the pound
• 45 is sold by the troy ounce
• Flux
• When brazing, silver flux must be used
• It cleans the metal and acts as a temperature
  indicator
• It assists in alloy flow and prevents oxidation

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SOLDERING BRAZING

• Heat both Fitting and Tube
• Flux will turn powdery white and suddenly clear
• Clearing is an indication of about 1,100F
• Apply alloy (braze), very little is needed
• Capillary action will take place
• Alloy (braze) will flow around 1,100F to 1,250F
• As flow starts, remove alloy and flame

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SOLDERING BRAZING

• Cool the joint and clean to remove excess flux
• Excess flux could hide a pinhole leak

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SOLDERING BRAZING

• Heating of the joint for soldering and brazing
• If heating at the compressor
• Do the joint closest to the compressor first,
  using a wet rag as a heat shield, you could also
  use heat absorbing paste
• Whether soldering or brazing, avoid overheating
  glowing red produces scale

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SOLDERING BRAZING

• EQUIPMENT
• Oxy-acetylene
• Extremely hot may also be used for cutting
• Not for residential or Roof Top use
• Intended for work shop and construction site use

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SOLDERING BRAZING

• Tanks
• B tank or MC tank sizes
• Can be an unguided missile if not properly
  secured, the tank is under 250 psi
• Impact as little as 15 psi can cause valve to
  rupture
• Tank is cork lined
• The valve is opened only ½ turn with a tank wrench

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SOLDERING BRAZING

• Safety
• Always secure the tank
• Leak test each time the tank is first opened or
  changed, using only a bubble solution
• Store and use in upright position only
• Acetylene is heavier than air can puddle on
  floor, removing oxygen from the room, resulting
  in an explosion hazard

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SOLDERING BRAZING

• Regulators
• 2 types
• Adjustable and non-adjustable
• Adjustable
• Flame is adjusted with the regulator, not the
  torch handle
• Non-Adjustable
• Flame must be adjusted with the torch handle,
  handle is not made for fine tuning

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SOLDERING BRAZING

• Hose, Handle, and Tip
• Should be leak checked when checking the
  regulator
• Tips are interchangeable
• New tips are called swirl tips, the give off a
  hotter flame for brazing larger tubing
• Blue tip of flame is the hottest

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SOLDERING BRAZING

• General Safety
• Never use pliers on any part of torch setup
• After use
• Shut tank off at valve
• Bleed hose
• Coil hose
• Light torch only using striker
• Wear safety glasses at all times
• Adjust flame for different sized tubing