Piping, Tubing, Soldering and Brazing PDF

Piping, Tubing, Soldering and Brazing RACM-140 Learning Objectives Demonstrate knowledge of refrigeration piping, tubing, fittings and their applications. Demonstrate knowledge of the procedure used to install piping, tubing, and components. Demonstrate knowledge of the procedures...

Piping, Tubing, Soldering and Brazing RACM-140 Learning Objectives Demonstrate knowledge of refrigeration piping, tubing, fittings and their applications. Demonstrate knowledge of the procedure used to install piping, tubing, and components. Demonstrate knowledge of the procedures used to solder/braze. Demonstrate knowledge of fasteners, brackets, hangers. Demonstrate knowledge of insulation, sealants, and adhesives. At the end we will fabricate hangers, install supports, Safety Checklist Tubing/Piping Purpose Tubing, piping, and fittings facilitate connections between system components. They allow oil to drain back to the compressor. Correct material and proper size are essential for tubing, piping, and fittings for system to operate as designed. Proper system layout and correct installation and procedures are crucial. Proper refrigerant flow throughout system. Handling/Storage Store with caps to prevent contaminants from entering. Prevent moisture from entering. Inspect prior to use. Keep oil/dirt out of torches. Store cylinders upright, with regulators removed. Inspect torch set/hoses prior to use. Tubing vs. Piping Copper tubing – plumbing, heating, refrigerant piping. Iron/Steel piping – gas piping, steam heating. Plastic Pipe – waste drains, condensate drains, water supply, water source equipment, high efficiency gas venting. Copper Tubing Copper tubing comes as soft drawn, or hard drawn. Soft drawn comes in rolls. Hard drawn comes in lengths. Soft drawn can be bent or used with fittings. Hard drawn is not intended to be bent, but can be annealed. Annealing is the process of heating the tubing, and bending it. Hard Drawn Tubing Types Type K – Heavy duty with thick tubing wall. Type L – Medium duty, most popular. Type M – Light duty, not generally used. Type DWV (Drain, Waste, Vent) – Lightweight, not used to carry refrigerant, but for other applications. Soft Drawn Tubing Rolls 3/16” to 1-3/8” O.D 25 ft – 100 ft rolls. Insulated/Bare Unroll on flat surface Do not bend/straighten more times than needed. Causes the tubing to become work hardened. Line Sets Tubing in bundles. Insulated liquid line/suction line. Some are charged with refrigerant, eliminating the need for evacuation. Some are charged with nitrogen, that must be released before installing. Some are just capped. ACR vs. Nominal Tubing ACR tubing is sized by the outside diameter, or O.D. Nominal tubing is sized by the inside diameter, or I.D. If the plans/spec calls for ½” ACR, the outside diameter would be ½”. ½” Nominal tubing would have a ½” I.D. 1/8” larger going from I.D to O.D. Ex. ½” I.D would give a 5/8” O.D. Purpose of Insulation Typically, on the low side of the equipment. (evaporator and compressor inlet) Its main job is to prevent the suction line from gaining additional heat. Remember, heat transfers hot to cold. Prevents condensation by providing a barrier from the cold gas to the surrounding air. Can be used to insulate hot/warm lines to prevent from losing heat, also for safety. Insulation Procedures Easiest to install before making final braze connection. Powdered coating allows for it to slide easily. Only need to glue the ends, rather than the whole length. Apply adhesive/glue to ends, allow it to become tacky, places ends together and hold for several seconds. Too much adhesive = insulation will not bond. Cutting Tubing Tubing cutters or hacksaw for large tubing. Place tubing in the cutter. Tighten wheel moderately, over tightening causes out of round edges. Turn wheel 1/8 of a turn per rotation around tubing. Reaming After cutting, there is a burr on the inside of the tubing. Burrs need to be removed as they affect refrigerant flow. Using a reamer, remove the burrs. Tip tubing upside down while reaming to allow coppers debris to fall out and not get into the system. Bending Tubing Joints/fittings should be kept to a minimum to prevent future leaks. Bending tubing removes this risk. Bending also eliminates contamination from poor brazing practices. Spring type, lever type, rachet type, line set benders. Copper Tube Bending Tools & Methods! Lever Type, Ratc heting, Spring, Hands! Soldering Temperature range/melting point is 361F - 500 F Used in plumbing/heating systems. Copper/Brass Filler materials 50/50 = 50 % tin – 50 % lead for moderate pressures, but cannot be used on water lines. Filler materials 95/5 = 95 % tin – 5 % antimony Flux for soldering is applied to the male end of the better-quality this removes oxides and improves heat transfer for a better-quality joint. Brazing Filler materials melt around 1205 F – 1550F Sil-Fos rods are 5 % silver, or 15 % silver, the rest is copper. Heat tubing first – allows it to expand into the fitting. Apply heat to the fitting until it starts to become cherry red. Start applying the filler material, heating when needed. You will see the flux/capillary action of the filler material as it is pulled into the joint. Cap ridge of joint by applying material. Heat Sources for Soldering/Brazing Soldering utilizes propane, butane or map gas. Brazing utilizes air-acetylene or oxy-acetylene. Choose proper tip for brazing, this varies with tubing size. Flowing with Nitrogen Flowing nitrogen in the tubing with an appropriate amount of nitrogen is needed while brazing, 1-2 psig. This removes the oxygen from inside the tubing. No oxygen means no oxidization. Oxidization leaves behind the flakes that will travel through the system, sticking in filter driers, screens of valves, etc. Brazing With and Without Flowing Nitrogen + Using Silv er Solder Rings Soldering and Brazing Pointers Clean all surfaces to be joined. Keep filings, burrs, and flux from inside the pipe. When making vertical joints, heat the top of the fitting to pull the material towards the heat. Apply wet rag to sensitive valves for protection. Dissimilar metals must be joined with silver solder, flux is needed. When joining steel to copper, most of the heat is applied to the steel as it will hold more heat, heating the copper. Heating the copper first would not allow the steel to get hot enough, and the filler would not flow properly. Flame Temperatures and PPE Always wear protective gloves and safety glasses suited for the application. Welding gloves offer great protection against burns. Propane Torch – 3600 F Butane Torch – 2600 F Air-Acetylene – 4200 F Oxy-Acetylene – 5600 F Flaring The ACR industry uses 45° angle flare. Flare nuts are meant to be torqued to certain specifications. Reaming prior helps create a better flare. A drop of refrigerant oil should be added to the back end of the flare, this provides a gap from the brass nut to copper flare. Flares should be redone if they are removed, the copper can become work hardened if not. Sealants - Nylog Sealants can be applied to threaded connections. Nylog is safe as it is made with the refrigerant oil, so if any gets into the system it will be okay. Nylog can be applied to the male threads, and also between the brass nut and copper flare. Nylog Blue is Compatible | The Ultimate Gasket & Thread Seal ant for HVACR Sealants – Fire Stop Fire caulking seals seams, gaps, and openings in fire- resistant walls, floors, ceilings, and around fire-rated doors to enhance fire safety by slowing or preventing the spread of flames, smoke, and toxic gases. Expands when heated. Applied to floor and wall penetrations of piping, tubing, and electrical. Swaging Process of joining two pieces of tubing the same size, through brazing or soldering. Swaging tools are punch type, screw or lever type. Punch type requires the flaring block to hold tubing, the punch fitting is place in the tubing and hit with a hammer until the tubing expands. Screw type uses the flaring tool with a different chuck. The chuck fittings can be changed depending on tubing size. Lever type tool has interchangeable heads for different sizes, insert the tubing and complete the swag. Swaging Copper Tubing! Hydraulic, Manual, Spin, Hammer, & Sta ndard Expanding Tools! Compression Fittings (RLS) Prepare tubing, removing burrs, sanding outside of tubing. Insert depth gauge and determine the insertion depth. Mark depth. Insert fitting. Align jaws with the groove and flare on the fitting. Hold trigger until the cycle is complete. Inspect joint and check for RLS stamp. RLS Step-by-Step Demonstration Supports and Brackets Supporting tubing is crucial to prevent damage and leaks from vibration. Manufacturers specifications. Horizontal tubing up to ¾” should be supported every 4- 6 feet. Horizontal tubing larger than ¾” should be supported every 6-10 feet. Vertical tubing should be supported every 8-10 feet. Tubing shall be supported when it changes direction.