HVAC Techs

Nov 30, 2023

It's been said that hackers are enamored with complex networks. In the 60s and 70s, the telephone network was the biggest around, singing a siren song to an entire generation of blue-boxing phone phreaks. I started a bit closer to the house. As a child I was fascinated by the heating system in the basement of our home: a network of pipes with a giant boiler in the middle. It knew when to come on to provide heat, and when to kick on for hot water. I spent hours charting the piping and electrical inputs and outputs, trying to understand how everything worked. My parents still tell stories of how I would ask to inspect the neighbors heating systems. I even pestered the maintenance staff at my nursery school until they finally took me down to see the monstrous steam boiler which kept the building warm.

My family was sure I would grow up to be a Heating Ventilation and Air Conditioning (HVAC) tech. As it turned out, electronics and embedded systems were my calling. They may not have been too far from the truth though, as these days I find myself designing systems for a major manufacturer of boiler controls and thermostats.

Recently a house hunt led me to do some HVAC research on the web. What I found is that HVAC techs have created a great community on the internet. Tradesmen and women from all over the world share stories, pictures, and videos on websites such as HVAC-Talk and HeatingHelp.

Heating Ventilation and Air Conditioning is one of the mechanical trades. Being an HVAC service tech isn't a glamorous position. However, if you wake up on a cold winter morning with no heat, he or she can be a life saver. For folks living in colder climates, this is often a literal statement. Carbon monoxide, freezing temperatures, and fire are just a few of the ways a malfunctioning heat plant can wipe out a family.

One of the most interesting jobs the HVAC service tech goes on is the service call. This is where they get to be the troubleshooter. It could be no heat on an oil-fired boiler in a home, or no cooling on a rooftop commercial air conditioner. Their task is to get the system running, and to do it safely. Some systems are beyond repair though. No tech wants to leave a family without heat, but if a system is creating a dangerous condition, such as leaking carbon monoxide into the home, there isn't really a choice. For those that can be repaired, techs have come up with an amazing array of hacks to get systems up and running safely. The best way to find out about these tricks and hacks is to watch some techs at work.

Thanks to the wonders of technology, we can now do that without climbing up on a hot roof or crawling through a dusty basement. An excellent community of techs has formed on YouTube. Techs like [Steven Lavimoniere], [Halligan142], and [Stephen Rardon] pack their cameras along with their wrenches and torches so we can ride along on their calls.

It takes a special kind of tech to record and post videos of their work. Any mistake, unsafe practice, or "half fix" will be picked apart in the comments. YouTube commenters are relentless, so folks making videos are very good or very brave or both.

The channels also outline how different work can be. [Halligan142] does a lot of work on small commercial systems. He can often be found on rooftops working on gas-fired heating systems, and AC units. Definitely check out [Halligan142's] series on machining, as well as building a proton pack for Ghostbusters cosplay.

[Stephen Rardon] does a mix of residential and commercial work in North Carolina. Many of his days consist of servicing heat pump systems. Steven also shows off many of the newer tools available to the industry. Rather than the old gauge sets to measure refrigerant pressure, he uses a system called iManifold. Bluetooth sensors attach to the refrigerant lines as well as the air feed and return. The entire system's performance can then be viewed on an Android or iOS phone or tablet.

[Steven Lavimoniere] hails from North Dartmouth, Massachusetts. His geographical area uses a lot of oil-fired hot water heating systems. That means he has to be a master plumber as well as an HVAC tech. His videos show how nasty oil service can be, especially on systems that haven't been serviced in a few years. [Steven] also uses new electronic test equipment. His Testo combustion analyzer displays oil and gas system efficiency, and even allows him to print a permanent record of the results. This is a lot better than older systems like the Fyrite. The old systems determined CO2 and oxygen levels by measuring the volume change in a liquid which absorbs each gas. Efficiency calculations are then performed with a slide rule based upon the change in liquid volume and exhaust temperature. The liquids were composed of some nasty chemicals such as mercury chloride (HgCl2) and chromium (III) chloride hexahydrate, which I’m sure techs like [Steven] don't miss.

You have to love Steven's accent too. I was brought up watching episodes of This Old House, so the Bostonian accent is a perfect pairing with working on old homes and their systems.

The commenters watching these channels are more like hawks than your run-of-the-mill YouTube trolls. Many of them are HVAC techs themselves. These folks are often speaking with the voice of experience. Just as electrical engineers have to deal with bad hardware design, or software engineers deal with tangled legacy code, HVAC techs often have to cope with poorly installed systems, bad service, and years of neglect on heating and cooling systems. Techs have come up with their own vocabulary for the types of problems they run into. The "Run Cap Bandit" is someone who throws a new start/run capacitor on a system with a failing compressor.

HVAC-talk, a popular website for techs, has an entire section dedicated to photos of the types of issues field techs run into appropriately called The Wall of Shame. Inside you’ll find scenes like this one – a water heater with an exhaust made of PVC waste pipe. It's never a good idea to vent 300+ degree F gas through plastic.

One question that often comes up is "can I work on my own heating or cooling system?" Here at Hackaday we are all about doing it yourself – but there are limits to what even we will try. While writing this article I took an informal poll of the writing and editing staff. Many of us have made repairs to our own systems – such as brazing joints on an evaporator coil, or replacing a thermocouple on a gas system. I myself have repaired broken pipes on my hydronic system, and have changed simple things like a clogged oil filter.

For major repairs though, it's always best to call in a pro, especially for oil and gas systems. Yes, even oil burners can do nasty things like explode when mistreated. (They’re not kidding when they say don't press that red button more than twice!) Professionals have the tools and the experience to ensure the system is running safe, clean, and minimize problems in the future. It's money well spent, and you might even be able to take a look over their shoulder and learn a trick our two.