Author: BryanOrr

Bryan Orr is the CoFounder of Kalos Services Inc. a Multi-Discipline HVAC/R Contracting Company in Central Florida as well as the creator and founder of HVAC School podcast, YouTube and Website

I hear the following phrase a lot

It’s the amperage that kills you not the voltage

While there is truth to the statement it is sort of like saying “it’s the size of the vehicle not the speed that kills you when it hits you”…

OK so that’s a pretty bad example, but hopefully, it gets the point across. BOTH of them are needed to cause injury or death and in the case of voltage and amperage the higher the voltage the higher the amperage.

This statement about amperage being the real danger as led to many people inaccurately believing it is the size of a panel or the gauge of wire that makes something more or less dangerous… which is 100% incorrect.

Let’s take a quick look at OHM’s law –

Amps = Volts ÷ Ohms 

The resistance (ohms) of the human body depends on a lot of factors including things like the moisture content of the skin, what other objects the current path is traveling through, what path the current is taking through the body etc…

While the resistances vary based on these factors Ohms law still holds true that when you increase the voltage you ALSO increase the amperage.

Take a look at this chart from the CDC

Effects of Electrical Current* on the Body [3]
CurrentReaction
1 milliampJust a faint tingle.
5 milliampsSlight shock felt. Disturbing, but not painful. Most people can “let go.” However, strong involuntary movements can cause injuries.
6-25 milliamps (women)†
9-30 milliamps (men)
Painful shock. Muscular control is lost. This is the range where “freezing currents” start. It may not be possible to “let go.”
50-150 milliampsExtremely painful shock, respiratory arrest (breathing stops), severe muscle contractions. Flexor muscles may cause holding on; extensor muscles may cause intense pushing away. Death is possible.
1,000-4,300 milliamps (1-4.3 amps)Ventricular fibrillation (heart pumping action not rhythmic) occurs. Muscles contract; nerve damage occurs. Death is likely.
10,000 milliamps (10 amps)Cardiac arrest and severe burns occur. Death is probable.

*Effects are for voltages less than about 600 volts. Higher voltages also cause severe burns.
†Differences in muscle and fat content affect the severity of shock.

Let’s say that a particular shock is traveling through a 20 KOhm (20,000 ohm) path in your body

At 120V this would produce a 6mA shock

At 240V it would be 12mA

At 480V it would be 24mA

It becomes clear pretty quick that higher voltage does lead to more dangerous shocks as does the resistance of the path.

High Resistance and Low Voltage = Safer

Low Resistance and High Voltage = Danger

This is why working around live electrical should only be done with insulated tools, proper PPE and in dry conditions. These all serve to keep the resistance up to reduce the likelihood of a fatal shock. The higher the voltage the more diligent you need to be.

Some people may bring up high voltage shocks from a taser or static electricity as proof that “voltage doesn’t kill”.

In these cases, the power supply is either limited, intermittent or instantaneous. This means that while the voltage is high it is only high for a very short period. Unfortunately in our profession, those sorts of quick high voltage discharges aren’t the big danger we face, most of the electrical work we do is on systems that will happily fry us to a crisp before the power supply cuts out.

A circuit breaker or fuse will never protect us because we draw in the milliamp range when we are being shocked as almost all fuses or breakers don’t trip or blow until much higher levels are reached.

Be safe around high voltage and keep your resistance high.

— Bryan

 

 

 

As HVAC/R techs we don’t do a lot of soldering generally unless you are in a shop that has embraced Stay Brite® 8 from Harris.

There are several aluminum repair products on the market that also use an indirect soldering type technique so this is is a general and generic overview of some best practices. As always, follow the manufacturer’s instructions for best results.

 

Prep the Work Area

When soldering you will want to get everything as clean as possible before you start. You can begin with brushes or Emory cloth to get the big stuff off then go to alcohol and a lint-free cloth at the end to get off any residue or silica particles. Just make sure any alcohol is completely evaporated before using a torch.

Another nice trick for tight work on aluminum coils is using a wire wheel on a Dremel to get the area clean. I had luck with this when repairing a microchannel coil.

 

 

Use Lower Heat Than Brazing

Often soldering is best done with an air-acetylene or MAPP gas torch rather than a typical oxygen rig especially when you have room to work. If you are working a tight space you may opt for a small oxy/acet tip like the one shown above but be VERY careful. The flame may be small and therefore put out less BTUs than a larger flame but it will still be a much hotter temperature than air-acetylene or MAPP.

Work Indirectly 

When working with solders or lower temperature base metals like aluminum it is generally best to heat around the repair or joining area with your rather than right on it. The goal is to allow the heat to gently conduct into the area ESPECIALLY when working with the hotter oxygen flame. With brazing, we can almost put the heat directly on the rod as we work and for most of these products, this won’t work at all.

Watch the Flux

Flux not only acts to keep oxides away from the work area, but it also gives us a visual indication of when the work area is at the right temperature to apply solder. If we underheat the work area the solder won’t flow int the joint and if we overheat the work area we will burn the flux and the solder won’t flow into the joint.

Another note on flux is we only want to apply it to the male end when joining and we don’t want to overuse flux and contaminate the system. Many fluxes are corrosive so wipe it all off one the joint cools to prevent leaks.

— Bryan

 

 

Let’s get something out of the way right off the top. Saying that we learn best “hands-on” is sorta like saying we prefer to breathe air…

WE ALL NEED TO APPLY THINGS TO LEARN THEM DEEPLY

David Sandler wrote the book “You can’t teach a kid to ride a bike in a seminar” and the same is certainly true for the trades.

But there is a distinction that needs to be made between “learning to ride a bike in a seminar” and “learning more about bikes in a seminar” or “learning about better riding technique in a seminar”  because these both could be valuable once you’ve already been riding a while.

This article is about HVAC training, but it’s also about things I’ve learned running a business, being homeschooled myself and home educating our kids as well as having a large family.

This is the perspective of one man so take it with a grain of salt.

I’m more of a hands-on learner

Inevitably when I teach a class, or give a seminar, or send an article or make a video or podcast or suggest that someone RTFM… there is someone who says some version of “I’m more of a hands-on learner”

Which… to be clear… is totally cool and should never be disregarded especially when learning an entirely new concept.

I went with my kids to the science museum the other day and the “Bernoulli table” with balls floating on high-velocity air streams created the “hands-on” and visual experience to illustrate Bernoulli’s principal.

It was a lot of fun and very interesting to see the balls suspended in the air, but imagine if I started to explain the principals of pressure and velocity and mass to the kids using words and they just look blankly and say “I’m more of a hands-on learner”.

Do you see the issue?

This is hands-on learning… it just isn’t ONLY hands-on learning.. almost nothing is ONLY hands-on learning if you want to understand what is going on.

Language needs to be used to explain the “why” behind something we can experience hands-on and if you refuse to listen or read the manual or plaque then you are left with experiences and observations that have no context or meaning.

To some degree, we are all hands-on learners but to really understand we would be well served to become, attentive readers and listeners as well.

You must be so patient 

It’s no secret that Leilani and I have 10 kids. When Leilani goes to the grocery store she gets three comments from people most often

  1. I don’t know how you do it
  2. You must be a saint
  3. You must have so much patience

We laugh because we ARE NOT naturally patient people AT ALL and we have no secret magical powers or heavenly bestowed holiness. People imagine that to have 10 kids and remain (mostly) sane you must have some special gift.

The truth is much more boring and mundane.

You don’t need a huge dose of natural patience, but you do need to work at being patient. You don’t need to be a saint but you do need to work to control your emotions when life gets crazy.

In the same way, you don’t need to be naturally gifted at listening or reading to learn, but it sure helps if you work at it

Obviously, some people are more academically gifted naturally than others and some people have learning challenges and disabilities. This isn’t to downplay that reality but I do think you would be better served to stop using it as an excuse.

Becoming a Visual Problem Solver

A visual problem solver is much like a hands-on learner in that they prefer to have a problem in front of them to find the solution rather than using words to describe it.

Some of the BEST problem solvers I’ve ever met weren’t big talkers, instead, they create images in their mind of a problem, structure or machine and work over the problem using the visual centers of their brain.

If you think about it, converting ideas and mental pictures to language is actually pretty inefficient if there is no reason to do so.

The challenge comes in when you need to communicate those ideas to another human.

If you start describing a problem to a visual problem solver they may request to take a look, or have a photo or screenshot sent to them, these are ways the visual problem solver has found to get around the challenge of translating things to language all the time.

They will often draw diagrams or ask you to draw diagrams and they may stare at them a bit as they build the visual model or “cartoon” in their head.

The visual problem solver doesn’t make excuses about how they prefer to learn. They don’t make it someone else’s fault that they aren’t getting a concept.

The visual problem solver finds workarounds to get things out of words and into their head where they work on it and ultimately SOLVE THE PROBLEM.

Take responsibility for the translation gap 

Good teachers find ways to meet their students where they are and teach to their learning style. The BEST teachers do the same and then ALSO teaches their students how to translate a world that doesn’t always cater to their learning style.

As a learner, it is our responsibility to take what we can from all sources and methods we can to learn how to problem-solve. I would argue that visual problem solvers actually have a HUGE advantage in our trade because by it’s very nature it is visual and hands-on.

It doesn’t change the fact that reading manuals is often the only way to get certain information and may continue to be a bit of a struggle. Where the person who always repeats that they are a “hands-on learner” may wait for someone to translate words on the page for them, the visual problem solver may build a cartoon in their head or doodle a diagram… whatever it takes to the solve the problem.

— Bryan

 

 

 

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