If you have spent any time around HVAC, either in a classroom or just chatting up an HVAC technician, there is a decent chance you’ve heard the expression “beer can cold.” “Beer can cold” is an expression that originated in the early days of air conditioning, back in the ‘50s and ‘60s. It was created to describe the temperature at which an air conditioning system has been properly charged with refrigerant.
The idea is if you were to grab a properly charged suction line it would be as cold as a cold beer can. It is also a completely irrelevant, incorrect, and outdated expression that shouldn’t be applied anywhere near modern-day HVAC. In fact, if you ever hear a fellow HVAC technician using that term earnestly turn the other direction and run away.
“Beer can cold” is an expression that no longer holds any relevance for HVAC technicians and should be left in the past. If you are an HVAC technician or in training to become one, here are three reasons to forget everything you may know about “beer can cold.”
What is “beer can cold” anyway?
One of the biggest arguments against “beer can cold” is that in a very precise industry this kind of measurement is not even remotely precise. What is the exact temperature of “beer can cold?” You can technically drink beer at any range of cold temperatures and different folks may have a different take on what the ideal temperature of a cold beer is.
Also, a beer out of a cooler full of ice maybe 32 degrees and one out of the fridge maybe 35 to 38 degrees, but they feel relatively the same to the touch. Air conditioners today are manufactured with distinct specifications on charging temperatures, and the tools HVAC technicians have at our disposal today make taking accurate temperatures much simpler than relying on getting a relative temperature by hand.
“Beer can cold” is misleading
Extremely hot working conditions are very common for HVAC technicians, especially here in Houston. If you were to grab a suction line that is about 50 degrees on a 100-degree day outside, that suction line is going to feel extraordinarily cold even though it is only 50 degrees. Now, if you grab that same suction line when it is only 60 degrees outside, it is not going to feel anywhere near as cold. Also, if there is a lot of moisture in the air, the suction line will be wet and feel colder than a dry line at the same temperature.
Aside from not having an exact reading for “beer can cold,” taking a temperature by hand can lead to horribly inaccurate and misleading readings that can lead to serious errors during installation and repair. Using this method on the job will likely cause you to make serious mistakes.
It’s not the ‘50s anymore
The truth about “Beer can cold” is that even though it is an expression that began in the ‘50s, it was an outdated expression even back then. So much about air conditioning in the past 60 years. Back then, compressors were oversized, coils had a lot of extra space, and fan motors were higher in horsepower. Flexibility in the charging of refrigerants was not a significant issue since a pound over or under would not cause any drastic changes.
Today’s air conditioning units are built much differently. Units are built to be just big enough, their coils are not oversized and their compressors are barely large enough. This all makes the efficiency rating of units higher, but also means the charge of refrigerant has to be within 2 ounces of the correct amount. Unlike the old days, air conditioners require a much higher level of precision.
The mantra of “beer can cold” is not only outdated, it was truthfully never a helpful or accurate reading to begin with. Here at the Training Center of Heating and Air Conditioning, we teach our students how to use the advanced techniques and tools at their disposal to do the job and charge the air conditioners they work on the right way, leaving “beer can cool” where it belongs: In your hands after a hard day’s work and you are relaxing at home in your hammock.
Learn more about enrolling in upcoming classes at the Training Center of Heating and Air Conditioning here.
HVAC technicians live a fulfilling and rewarding profession, perfect for anyone looking for a skilled profession in the trades. But, as rewarding of a career as it is, it is a job where professionals need to maintain vigilance at all times and practice extreme safety at all times from the potential hazards they may face.
The nature of a HVAC tech’s job can put them in some precarious positions due to where they work, how they work, and the equipment they work with. Both current and aspiring HVAC technicians as well as those looking to operate their own HVAC business need to be aware at all times of the hazards they and their employees face during the course of their work day and how they can best take the necessary steps to avoid them and be as safe as possible at all times.
During the dog days of summer here in Houston, life can be a little rough for air conditioning technicians. They work long hours in hot conditions running from job to job with often very little downtown in between. All of this can put a great strain on technicians and cause a tremendous amount of fatigue. When HVAC technicians become fatigued they run the risk of making mistakes or losing alertness which won’t just result in poor service and installation but can also put them and their customers at risk of harm from many of the hazards we are about to cover, potentially falling asleep at the wheel between jobs, and dehydration.
It is important during the course of a work day for HVAC technicians and the company that employs them to take the necessary precautions to avoid fatigue to ensure safety and performance. Technicians need to make sure they stay hydrated throughout the day, take breaks for rest when necessary, don’t skip over meals, and alert their employers or dispatches when rest is necessary. HVAC employers also need to be aware of their workers’ needs and schedule their jobs accordingly.
Particularly when working on commercial heating and cooling systems, HVAC technicians will often find themselves in some fairly high environments whether they are on top of a roof or on a ladder accessing ductwork or vents in a ceiling or attic space. In these situations, the dangers of falling from a high location is very real and can result in serious bodily harm.
Any technician that will be working at heights needs to practice extreme caution. Always check and double check the location of ladders and scaffolding you need to use to ensure it is sturdy and secure to use. Always have a spotter when you can and in extremely high environments, the use of a safety harness should always be insisted upon.
In between the open flame used in some heating equipment, the natural heat that air conditioning and furnaces can produce, equipment sitting in the hot sun, and soldering (which is a practice that is sometimes used during HVAC installations and repairs) the average HVAC technician has no shortage of opportunities to burn themselves both mildly and severely.
Practicing the utmost caution around hot or potentially hot equipment is a must for technicians, especially here in Houston. Always try and make sure equipment is cool before you start working on it, but also be sure to wear the appropriate protection of heat-resistant gloves when it is appropriate for extra protection. Even on a hot day, long sleeves can help protect your arms from incidental contact with hot objects.
HVAC work involves frequently interacting with electrical equipment and wiring. One false step can mean you face harmful electrocution. Not only is electrocution harmful to the technician, but if fatigue is also a factor, a live exposed wire left unattended could also mean harm to the person they are servicing.
Electric shock can happen in an instant, and it can be difficult to tell if a wire is live or not. Therefore, safety against electrocution should be one of the primary concerns of HVAC technicians at all times. Always carry the proper equipment necessary to test the charge of wires before interacting with them and always be sure to wear protective gloves when working with electricity. If necessary, you may also consider shutting off the power to the area you are working on prior to beginning service as an extra precaution.
Safety is a very important aspect of being a successful HVAC technician and safety is also a primary focus of what we teach here at the Training Center for Heating and Air Conditioning. Our instructor, Chris Walters, takes an extensive amount of time dedicated to teaching and reinforcing proper HVAC safety to avoid these common HVAC hazards.
Learn more about enrollment in a future class today.
Why is it so important to understand what a normal HVAC system looks, sounds, and feels like? Simply put, you must know normal before you can diagnose abnormal. Adopting this philosophy will have a profound impact on how you see and work on almost everything.
No matter what you are doing, if you know what is normal, you will be much more confident in the outcome. Technicians that don’t realize this tend to make many mistakes, incorrect diagnoses, and improper installations. What impact will this have on your HVAC career?
Normal Isn’t Always Good
It should go without saying that normalcy in an HVAC system isn’t always a good thing. For example:
- It’s normal that most a/c systems are installed incorrectly.
- It’s normal for technicians to ignore superheat and subcool when charging or testing a system
Even if being normal isn’t always a good thing, it’s still important to recognize what a normal system looks like. If you know that most systems are installed incorrectly, it will make you look harder and not assume anything. If you know that most technicians ignore proper charging procedures by ignoring superheat and subcooling, you will take a closer look at that even though you may be there for something entirely unrelated to the refrigerant charge.
Sometimes knowing normal is knowing how something reacts when it fails. For example, if a liquid line drier starts to clog up, it’s normal for a temperature drop to be detectable from the inlet to the outlet side. It’s also normal for a clean drier to not have a temperature drop. Both of these are the norm for that particular situation, but both equally important to know.
On the other hand, two seemingly opposite functions could also be normal. For instance, an evaporator coil will produce a large amount of water if the air is high in humidity, and none at all if the weather is dry. If you don’t know the difference, you might misdiagnosis a problem based on incorrect knowledge of what the system is supplied to do. Just the fact the coil does or does not produce water means nothing if you don’t understand the differences.
Pro Tip: Even if you notice fluctuations in certain HVAC functions, don’t assume that means there’s a problem. The system may be designed to handle or cause those changes. Stay informed of real problems to watch for.
“Normals” of HVAC Compressors
How much do you know about the normal functions of HVAC compressors? Let’s just consider the temperature of the shell of the three compressors. The scroll on the top of the compressor should be very hot since that’s where the head discharges into the dome. In fact, the entire dome should be very hot anytime the unit is turned on, while the sides are cooled by suction gases and will not be nearly as hot. Since the reciprocating compressor is also cooled by suction gases, you should only notice heat where the hot gas line leaves the shell.
If a technician touches a rotary and assumes it is overheating because he confuses it with a scroll, they’ll misdiagnose a system issue and perform unnecessary work. Similarly, touching a hot reciprocating compressor and assuming it is operating normally because you don’t know better will allow a potentially severe problem to get worse.
Know What a Normal HVAC System Looks Like
It’s been said that “You must know normal before you can know abnormal”. This saying is particularly true in an industry that deals with troubleshooting. The first step toward identifying a problem is knowing what normal operations should look like and what any deviations from the norm could mean.
Connect with us to learn more about normalcy in the HVAC industry and how to identify common issues.