Author: Bryan Orr

Bryan Orr is a lifelong learner, proud technician and advocate for the HVAC/R Trade

For years I’ve worked with and around people who view work, problems and goals differently than I do. I’ve often told my wife that I have an issue managing and leading administrators, salespeople and other inside staff because I just don’t communicate in a way they seem to like.

It’s been 20 years in the trade now and almost 15 in business before I’ve come to a conclusion.

I prefer working with technicians

Before you call all the dispatchers, accountants and warehouse staff together with pitchforks and Molotov cocktails… hear me out

What is a Technician? 

We aren’t going to reach for a dictionary to define what a technician is, we are going with the “Potter Stewart” method of “I know it when I see it” and I’m sure you do as well.

Now, there are many people with the title of “technician” on their LinkedIn account that don’t meet my smell test and there are many more who would never consider that title who are hard core technician in my book.

A Technician Wants to Understand

There is a big difference between knowing what to do and understanding. I was standing in line at the local fast food joint the other day and I was noticing all the teenagers moving around behind the counter, looking up at monitors,, hitting buttons, filling drinks and wrapping burgers.

They all knew what to do to get me my food at Mickey D’s but put them in front of some raw ingredients in a home kitchen and do they UNDERSTAND cooking? No, of course they don’t.

If you handed them a hot-dog and they had never made one before they would look at you, blink and then ask some version of “how do I cook this?”. They will keep standing there until someone gives the answer and in their mind that is how cooking food works. Someone tells you what to do and then you do it the way you are told, this is how you cook and this is how having a job works in their world.

For the technicians out there, is that how you learned? is that how you solve problems? The idea that we would wait until someone tells us how to do everything before we do it is laughable. Technicians found how the why and how of how things work in order make sense of solving problems, even problems they have never encountered before.

This doesn’t mean a technician has all the answers, there are far too many questions for anyone to have all the answers, a technician just works on a problem until they understand the factors involved and can make a diagnosis and repair even if it’s imperfect.

Technicians Take Their Work Seriously 

A true technician may be light hearted or severe, introverted or extroverted but they all take their work very seriously. When they put their name on something it means something and they never want it to be said of them that they were careless, lazy or sloppy in their work. In a technicians mind their work is nobody else’s responsibility and they want to get it right the first time.

A Technician Doesn’t Need to be Affirmed Continuously 

I’ve noticed this new phenomenon where workers expect not only to be recognized for their achievements above and beyond the usual but to get verbal affirmation just for the regular execution of their job. It’s as if  every job task completed without a serious mistake is a huge accomplishment and requires commentary.

Technicians get satisfaction from a job well done, they pursue excellence for excellence own sake, not for the accolades of others ESPECIALLY when it’s given because its expected.

A Technician Goes Home When the Days Work is Done 

Technicians don’t go home until their work is done. That doesn’t mean that they always work crazy hours but it does mean that they don’t start something that they aren’t going to see through to completion, even if that means handing it off to someone else.

I’ve had numerous interactions with staff who were getting behind in their core tasks because they “just don’t have enough time”. A technician doesn’t get behind for long because that just isn’t an option for them. There is another job to do and the only way to keep from drowning is to get better and more efficient at their work. If a technician is given far more than they can do then they talk to the dispatcher or manager to get help BEFORE they get stuck because just leaving it undone is off the table.

Technicians Fix Problems

Oh no! you have a problem that’s hard to figure out?

Technicians LIVE for the hard problems, the challenges they’ve never faced before, the once in lifetime issue.


Because to a technician work isn’t about showing up, doing the least possible work, staying comfortable and heading home a few minutes early if they can get away with it. Work is about fixing real problems, hard problems. Leaving everything you work on working better than when you started. Finding those hidden problems that everyone else missed and bringing harmony to discord.

To a technician every problem has a solution and if you aren’t working on the solution then WHY ARE YOU EVEN TALKING RIGHT NOW?

Technicians HATE Having Their Time Wasted

Standing around and shooting the breeze is OK every once and a while but to a technician it gets old real quick. A technician understands that the real work that pays the bills doesn’t get done by talking around the water cooler and the longer you put it off the tougher the day is going to be.

Technicians do not practice wasteful, non-sense processes without speaking up, even if it was their bosses idea or pet project. If a technician finds they are working at a place that wastes their time on useless reports that nobody ever looks at or double entry data procedures that has them writing more than they are working they will usually move on pretty quick.

Don’t ask a technician to train a slacker or suffer a fool in their work space, a technician would fire their own grandma if they slow them down and cause issues.

Technicians Don’t Need Emotional Support to Do Their Job 

I’ve overheard people say that they “don’t feel supported” in their jobs on more occasion than once. If that means you aren’t being given the time and tools to deliver on what the company is requiring or promising than I guess I understand that. If it means you need someone to call and talk you through problems every-time you feel frustrated or that you need to talk to someone whenever a customer gets cranky then the technician in me says

Buck up Buttercup. It isn’t supposed to be easy and you won’t always “feel good” about every job or interaction.

A technician is an adult who doesn’t need someone to make them feel good about life in order to get the job done. So much of what people call “communication” is just empty talk designed to make people feel “heard” and that they could “Speak their piece”.

This doesn’t mane you need to be rude or nasty but what is with all this talking and meetings and talking about meetings!!

You know what makes a technician feel better? GETTING WORK DONE

Technicians Hate Failing But Accept That It’s Part of Growing 

There are two common workplace responses to mistakes and failures when they come to light. The most common is to make excuses and place blame, the technician figures out what went wrong and learns ways to prevent it in the future to the extent it is preventable.

It always cracks me up when something breaks and the customer acts totally stunned and says something like “That shouldn’t happen! This system is only _____ years old”as if someone must account for this horrible injustice.

Yes and war and sickness, crime and decay ALSO shouldn’t happen but they do every day, technicians realize this and embrace it as part of their calling to set things right rather than wallowing in blame and excuses.

Technicians Don’t Ask Social Questions

If a technician is really stuck and need some expert advice then they MAY call another technician but only after they have read everything they can on the problem they are facing and took a solid shot at Google or any other online resources they have. They don’t call other technicians just because it’s “easier to call” and “I just wanted to talk”. If you want to talk to another tech when you are both on the way home to catch up on the events of the day then OK (we used to do this all the time in the days of radio dispatch), but technical questions are for specific technical answers not for chit chat.

My Epiphany

I realized that I am not going to stop preferring technicians.

So rather than trying to change that about myself, I’m going to work to fill my business with people who have a technicians mindset even if their job title isn’t one of a technician. The best dispatchers, receptionists, permit techs, parts counter staff, warehouse managers and installers I have known still have this “technician” mindset even though they may never work on a piece of HVAC equipment.

From now on I’m looking for dispatch technicians, sales technicians and warehouse sweeper technicians (you get the point). Sure a successful workplace takes all types of personalities and skill sets and if you are coming to work to get stuff done and broken stuff fixed then WELCOME. If you want a support group or new friends than may I suggest the Kiwanis club or Elks Lodge (that’s a thing right?).

— Bryan


Illustration Courtesy of Emerson

CO2 is a pretty nice refrigerant.

It has zero ODP (Ozone depletion potential) and a GWP (global warming potential) of 1. CO2  has been used as a refrigerant almost from the very beginning of refrigerants and its been making a big comeback in market refrigeration (especially in colder climates).

CO2 (R744) is naturally better suited for lower temperature refrigeration applications because of its low temperature saturated state at atmospheric pressure (-109.3F). You will notice I said “saturated state” because CO2 does not “boil” at atmospheric pressure. At any pressure below 60 psig CO2 goes straight from solid (dry ice) right to a vapor, This is why 60 psig is known as the “triple point” or the point that could be either solid, liquid or vapor.

Now go to the top of the range with CO2, when you apply 1055 psig the saturation temperature is 87.8F but go up even 1 more degree and CO2 CANNOT be liquified, this is known as the critical point of the substance. Whenever a substance is forced beyond it’s critical point it becomes what is known as a supercritical fluid and has properties that are unique to this state but it is certainly not a liquid. You can see more in this natural refrigerants PT chart.

In a transcritical (trans means beyond or through so transcritical means “beyond critical”) booster refrigeration system the low temp portion of the system operates using it’s own compressors that “boost” the refrigerant from the low temp side and discharge into the suction of the medium temp side. The high stage compressors then pressurize the CO2 (R744) above its critical pressure / temperature.

What is traditionally called a condenser becomes a gas cooler and decreases the temperature (rejects heat from) of the discharge without actually condensing it into liquid. The cooled supercritical fluid goes through a pressure reducing valve, where some of it condenses into liquid and the rest remains as gas. Liquid and gas are separated in a flash tank (receiver). Pressure in this tank are usually controlled to around 450 to 500psig.

It’s super critical that you understand all of this…

See what I did there.

— Bryan



This tip is written by HVAC Applications and Technical Specialist Dakota Brown. Thanks Dakota!

As a technician it was always the same old story

Are you done yet?

There was always pressure from the office; either from the dispatcher, service manager or project manager to get the job done and get it done quickly.

When I became an estimator and project manager at the company I worked for I tried not to fall into the trap of pressuring the technicians (my former brothers-in-arms) to get the job done quickly by cutting corners but I’m sure I fell victim to that mentality a time or two.

Now that I work for a distributor and I am doing technical support including start-ups I can look at one of the biggest problems facing contractors more objectively. You all know what that problem is at this point or at least you should.


We all talk about being thorough on service calls to prevent those dreaded call backs. But what about on installs? We all like to complain about [insert brand here] and how their equipment stinks but we all know that most issues with new equipment come from a bad install or worse yet, a bad start-up (GASP!)

“But I am always thorough on my start-ups!”


We’ve all gotten the call asking if we are done yet. Or, if we are coming home! We start to cut some corners to get packed up and neglect checking gas pressure (I’m sure it’s fine) or airflow (I hear the fan running) and pack up.

75% of the service calls I get on new equipment come from bad start-ups. Even when a contractor does the best install possible they can blow it right at the end with a bad start-up.

That is why I say “almost.”

I liken it to a race. Nothing drives me nuts while watching a race or any other sporting event more than seeing someone pull up at the last-minute, right before the finish line.

Run through the finish, don’t pull up at the end.

Time and time again I see a good install go bad. So, let’s talk about a few key points.

  • Check your voltages on a 208/230 volt unit. Most RTUs and splits that are dual voltage have multiple taps on the low voltage transformer and if you don’t have the incoming voltage tapped right you won’t get proper outgoing voltage.
  • Make sure your trap has a large enough drop to prevent condensate being sucked back through and inspect the drainage while it’s running.
  • Check phasing, seriously. It is simple enough to do beforehand with a phase rotation meter and keep in mind that VFD’s can correct phasing so just because your condenser fans or blower run the right direction that doesn’t mean the phase direction is correct in there is a VFD driving the motors.
  • If your unit has a smart control board (I’m looking at you York) make sure you configure the board to reflect what you just installed.
  • Check your economizer in all modes.
  • Airflow, airflow, airflow. This is the biggest one, really. I mainly work with York these days and they have what is called a dry coil pressure drop in their manuals. Using some ports built into the unit and a manometer with some metal tubing you can get the static pressure drop across the coil. This allows you to estimate airflow moving through the unit. This is so simple and a lot of people don’t do it. I understand this is just a starting point but we don’t live in a perfect world and not everyone has an in duct anemometer.
  • Owner training!!!!! Teach the end user how to use their new equipment, educate them on maintenance requirements, tell them something!

A lot of issues can be solved by reading the install manual and filling out the start-up sheet that comes with the equipment. If you don’t have one with the equipment, make one.

We could go on and on with start-ups and proper start-up practices and maybe we will but for now lets all try to remember that rushing off of the job to get to the next one will catch up with you and your reputation.

— Dakota Brown

Deburring copper tubing (often called reaming) is the practice of running a blade around the inside of tubing after you cut it to remove the burr edge from the inside.

It’s an important practice and should be performed whenever practical to reduce turbulence inside the lines that can be caused by the burr…. HOWEVER


Whenever possible point the open end downward while you run the blade around the inner edge and then tap the line to ensure that the shavings fall out of the line rather than in. In some situations during repairs it may make sense to purge nitrogen out the line you are deburring especially in repair situations like replacing a compressor where making the lines point downward may be impossible.

If you are given the choice where you must choose between deburring and possibly dropping shavings into the system I would rather you didn’t deburr.

In the case of making flare connections deburring is critical. For a flared tube it is also critical that you don’t over ream the tube and thin out the copper edge otherwise it will be prone to cracking.

In summary…

Deburring is important, but keeping shavings out of the system is even more important.

— Bryan

Evaporator temperatures below 32° are common and acceptable in refrigeration, that’s why there is a defrost sequence.

In a heat pump running in heat mode,, it’s the same, freezing is a part of the process and defrost is necessary.

In comfort cooling… we can’t allow the evaporator to get below 32°… or it will freeze.

I can’t tell you how many times I look back and technician notes and can see in plain black and white that the system will freeze.

And that is not OK…

Freezing causes flood back, no cooling, water damage and biological growth.

We cannot leave a system that is just going to freeze.

The image above is of the Danfoss refrigerant slider app and it shows that when suction pressure drops below 102 PSIG on an R410a system…. the coil hits 32° and will start to freeze.

This means that we need to setup equipment so that it will not freeze during normal operating conditions.

A typical residential A/C system should be setup so that the return temp can get all the way down to 68° and still be just above freezing.

Let’s say it’s 78° in a house on an R410a system and your suction pressure is 108 PSIG (like shown)

Your suction saturation (coil temperature) is 35°, and so the coil won’t freeze.


The coil temperature will drop approximately 1° for every degree the return temperature drops. So if the customer sets it down to 74° the saturation will now be 31° and the coil will freeze.

Pretty basic stuff but very important if you don’t want to leave a problem for your customers.

There are many things that can cause this (low airflow, restrictions, low refrigerant) but step #1 is having the wherewithal to catch it.

Keep in mind that this is only once the system has run long enough to stabilize. Don’t start making changes until the system has run at least 10 minutes and leveled off.

— Bryan

This tip comes from market refrigeration and controls technician Kevin Compass. Thanks Kevin!

A little tip when changing liquid cores. If you start pumping them down begin bypassing discharge gas into the shell to warm it up and to push out the remaining liquid and bring the shell above dew point so it doesn’t sweat when you change the cores.

This helps drive out the liquid refrigerant in the shell and helps prevent moisture contamination from condensation in the shell.

Work quickly so the system is open for the shortest possible time.

Two spring clamps make holding the lid on the cores cake so you can put the bolts back the easy way.

Before the fighting starts about term definitions let’s just settle on using adjustable drive pulley and sheave interchangeably to describe the belt driven power transmission device shown above.

Second, for the newer tech you shouldn’t be altering these sheaves so the belt rides lower or higher in them unless you know EXACTLY what you are doing. You can mess up the air balance , change sensible heat ratios and impact fresh air intake by adjusting the sheaves.

If you want to adjust belt tension, that is generally done by adjusting the motor mount using the tension adjustments made for that purpose. Belt tensioning and belt replacement is a part of regular maintenance, adjusting sheave halves isn’t.

In some cases you may find yourself in the position where you are replacing a sheave or where you need to adjust a sheave to increase or decrease blower RPM or airflow.

When Replacing a Sheave

Sheaves, like all pulleys, do tend to wear over time. When they wear it is better to replace them them rather than attempting to adjust them

Make sure to use the same diameter and count the number of turns “in” from the edge or edges on the old one and do the same on the new.

Only tighten the set screw on the “key” or flat to keep from damaging the sheave threads.

When making a sheave change

See the image above. The drive sheave will obviously rotate at the same RPM that the motor rotates. The RPM of the driven pulley on the blower is dictated by the size ratio of the drive to the driven pulley.

As you can see above, if the drive pulley has 1/2 the diameter of the driven pulley the driven pulley will rotate at 1/2 the speed of the motor.

In the scenario shown above the drive pulley is 6″ and turning at 1000 RPM and the driven pulley is 12″ and turning at 500 RPM.

Let’s say we wanted the driven pulley to spin at 600 RPM rather than 500. All we would need to do is divide 600 by 500 to come up with 1.2.

You then multiply the drive pulley diameter x 1.2 to get 7.2″ (or about 7 3/16″) to get to that RPM.

In practice, adjusting a sheave to get a belt to ride lower (closer to the shaft) or higher (further from the shaft) won’t usually result in huge airflow changes, but it will have an impact.

The main thing to know when adjusting an adjustable drive pulley is –

Riding lower / Halves Further = Less Air

Riding Higher / Halves Closer = More Air

When you do make an adjustment you will need to re-tension the belt and it’s a good practice to measure before and after blower amperage to see the impact of the change on the motor.

Never make a sheave change that results in a blower overload.

— Bryan

I’ve heard the phase “It’s too cold to set the charge” for as long as I’ve been in the trade.

“We need to come back and set the charge” or we need to come back to do XYZ other thing.

Granted, there are cases where you do actually need to come back, but it in my experience a lot of this is just punting the ball to the next tech. Admittedly, I’m in Florida so if you live in the great white north you will likely be doing your A/C startups in the Spring. Understandable.

So here’s the next questions you need to be able to answer if you are going to say you “can’t set the charge”.

#1 – Have you read the manufacturers specs on how to properly charge? They will have low ambient charging info and much more. Look it up.

#2 – Have to taken Suction, Head, Subcool, Superheat, Delta T and static? If not you haven’t done your full due diligence.

#3 – For systems with no data do you have a good feel for the common rules of thumb related to charging? If not you are in the right place, we have a ton of past articles on charging.

#4 – Drive up the condensing temperature (on TXV and EEV systems) and check the Subcool

One of the best ways to drive up head pressure in a controlled manner so that it can stabilize is the Fieldpiece charging jacket. You can control the top opening size to drive up the liquid pressure until you get to a pressure higher than the minimum pressure difference across the valve. I will often use a 100° condensing temperature as a rule of thumb if the manufacturer doesn’t give a guideline though many will use 110°.

Return trips leave the system running improperly, waste money and annoy your co-workers. 

Sometimes you have no choice but to setup a return trip for a warmer day, but any job you can finish the first time is time and money saved for you and the customer.

— Bryan


Sometimes you find yourself in a position where you are going to replace a fancy thermostat with a simple one. It may be because the customer got fed up with all the options or because you are there on a weekend service call and all you have is a basic stat.

No matter the reason you need to make sure the new thermostat can do the job the old one did before you quote, an option that gets overlooked in matching up is dehumidification.

Most manufacturers of residential variable speed air handlers have a terminal that will drop the blower speed when de-energized. It may be marked DH or D or dehum or something else. From the factory, they generally have that terminal connected to R using a pin or jumper so that the blower will run up to full speed. When one of these special thermostats get installed the tech is supposed to remove that jumper or pin and connect a wire from that terminal to the thermostat dehumidification terminal so that the thermostat can energize the terminal for full blower speed or drop 24v to the terminal to go into dehumidification.

If we install a new thermostat and forget to reconnect that pin or jumper then the system will ALWAYS run in dehumidification mode because there will never be any power on that terminal at the air handler board.

The lesson is to pay attention to whether or not a system is wired for dehumidification. If you do need to replace it with a basic thermostat make sure to replace the pin or jumper (J1 on the board example above).

If you forget to do so the system will run less efficiently with lower airflow, suction pressure and coil temperature.

— Bryan


Grounding is an area of many myths and legends in both the electrical and HVAC fields. This is a short article and we will briefly cover only a few common myths. For a more detailed explanation I advise subscribing to Mike Holt’s YouTube Channel HERE

Myth – Current Goes to Ground

Actually current (electrons) move according to a difference in charges/potential (Voltage). When a potential difference exists and a sufficient path exists there will be current. In a designed electrical system current is always returning to the source, the opposite side of a generator, transformer, battery, Inverter, alternator etc… current only goes to ground when an undesigned condition is present and ground (earth) can be a VERY POOR conductor at times. The only saving grace for the earth as a conductor is all of the parallel paths created with a ground rod because of all the surface area contact to earth.

Myth – To Be Safe, Add More Ground Rods

The ground can be an exceptionally poor conductor. The purpose of ground rods is to carry large spikes in current that comes down your electrical distribution lines away from the building. Adding more ground rods can actually EXPOSE the building to current from near ground strikes. Adding more rods isn’t always the solution and often does nothing useful.

Myth – Connecting Neutral and Ground Together In Multiple Places Is a Good Idea

Neutral and equipment ground should be connected in only one location at the main distribution panel to prevent the grounding conductors from carrying neutral current. If the equipment ground is carrying any current there is a problem.

Myth – Electricity (only) Takes The Path of Least Resistance 

If you have ever wired a parallel circuit you know that electrons travel down ALL available paths between to points of differing electrical charge.

Myth – Common, Ground and Neutral are the Same

Not even close. Common and neutral are terms used to describe the one side of a transformer. They are not grounded unless you ground them and when you do you are designating which side of the transformer will have an electrical potential that is equal with EQUIPMENT GROUND. The earth itself simply acts a really poor and erratic conductor between points of electrical potential that we designate and should not be confused with equipment ground.

Myth – Ground Rods Keep Us From Getting Shocked

Nope. Proper bonding connection between appliances, switches and outlets and equipment ground connected back to neutral at the main distribution panel in conjunction with properly sized circuit breakers and GFCI equipment keeps us safe. Grounds rods have little to nothing to do with protecting you from a ground fault.

Here is a great video on the topic and  you can find an article defining grounding and bonding terms HERE


— Bryan

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