HVAC Techs – Hackers Who Make House Calls

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.

roweHeating 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.

Soot-clogged oil fired boiler

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.

Testo 320 and its various gas sensors
Testo 320 and its various gas sensors

[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.

Don’t do this!

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.

44 thoughts on “HVAC Techs – Hackers Who Make House Calls

  1. I think it’s just fine for a homeowner to attempt to work on their own house… as long as they get a building permit to do it.

    I’ve had professionals come in and do things to our house that strictly speaking required a building permit without getting one, but that’s because they’re our “go-to” guys. I’ve only once run into a situation where this didn’t work out – we had a gas pipe installed in our fireplace for a log lighter and the professionals we hired used (pipe) unions indoors, which for gas is a terrible idea. We were clued in because they didn’t finish the job on time, and we hired someone else who told us to stop the check, take pictures of the old work and get a building permit and he redid it (he is now our go-to plumber).

    The whole point of getting a building permit is that you get a building inspector to come and check the work when it’s done. In our case, one of the things that the building inspector insisted upon was a pressure test, where the gas supply valve was shut off and an air pump used to pressurize the gas piping. A pressure gauge had to show no visible drop in pressure over a certain amount of time for it to pass.

    Even things that aren’t overtly dangerous to life and limb are things a homeowner probably ought to have looked at when they’re done. Plumbing errors – as a class – aren’t generally as deadly as HVAC errors, but they can cause catastrophic and costly damage to your house (burst pipes, leaks, etc). Building inspectors are there to give you peace of mind when the job is done.

    1. I’ve redone a TON of stuff at my house that inspectors ok’d but didn’t meet code. I also did half my basement and pulled permits. The inspections were a joke, the guys showed up, asked for a check and did a 30 second tour and left. I wouldn’t say permits are a savior. And note that towns get to choose their revision of code. So while my town didn’t require the new electrical outlets with built in child safety devices I took it upon myself to install them because they were code in many other places (and now are in my town just a few years later).

      Researching yourself using all the tools available these days (forums, blogs etc) is the smart choice and if you decide to pull permits then at least you should know what you should be doing and if the guys coming out to check your work are just checking a box or actually doing their jobs..

      1. I’ve had a different experience with my local inspectors. They thoroughly inspected my work and the work I had hired subs to do. They answered questions I had which let me double-check that the choices made were appropriate. Out of a handful of pulled permits there was one recheck necessary and that was about a 30-sec “Yep, you fixed it right” type of experience. All together positive, useful, and good for my own DIY peace-of-mind as Nick mentioned.

          1. Biggest lesson I learned when doing homeowner wiring – Make It Look Neat! The cleaner the job, the less likely the inspector goes looking for trouble.

            And inspectors do vary from place to place. When my dad built his own house, he got along great with the inspector. Asked questions ahead of time, listened to explanations, and was actually able to (respectfully) challenge and overturn some decisions.

            Whereas others I know in the trade have no shortage of horror stories of inspectors blindly quoting building code just to throw their weight around.

    2. I’ve been told that inspectors are not there to determine if the installation is safe, but to determine how much to increase your property value due to improvements come tax time. I’m sure they are not all like that, but don’t rely on them to tell you if everything is up to code or not…

    3. “…and the professionals we hired used (pipe) unions indoors, which for gas is a terrible idea”

      Huh? It’s pretty much impossible to cut into a section of existing black iron gas pipe without using a union. Additionally, either a union or a compression fitting should be used everywhere an appliance connects to the gas system, just past its shutoff and sediment trap. If your plumber can’t seal a union, that’s the problem, not the union!

      There’s plenty of licensed professionals out there who don’t seem to be able to do a good job when it comes to black pipe. I guess the new yellow flexible stuff gets them by without ever having to learn how to work with black pipe.

      1. Our installation now has no unions indoors. As it was explained to me, unions are more prone to leakage. That’s ok outdoors because it will be ventilated away, but absent that, a leak of any kind can cause a build-up, which has obvious safety implications.

        1. Pipe unions are not great, but the alternative is worse: Without them you have to disassemble and re-dope and assemble the piping every time you need to pull the burners and gas valve for service. Hope the threads survive!

          Unions typically only leak if you are careless (damage to the mating surfaces, insufficient tightening) or are cheap (poor quality fitting, re-using old rusty fitings). In many locales iron pipe is mandatory for gas connections to residential furnaces (no flex hose or couplings allowed), so unions are the only option. House explosions are statistically a non-event.

          THAT SAID: if you do smell gas, and suspect the union, there should be a shutoff valve upstream. Shut it off, open a window, and get it dealt with, either professionally or not.

          1. There are “left rights” , they are reverse threaded connectors that tighten both ends by rotating the connector, normal threaded pipe connectors are righty tighty, lefty loosey as anything else normal, the “left right” connector will typically be spray painted to signify its I

      2. >licensed professionals out there who don’t seem to be able to do a good job when it comes to black pipe.
        *cringe* like not using a simple square against the pipe? and not filing the OD 1/16 at 45 degree before using a NPT die and simple bubble level or plumb line to make sure they are threading straight?

        How do they even have a license?

    4. We had a house built in 2002. I’m still in the process of converting the plumbing to all CPVC. I have a well with acidic water, so while I neutralize the acidity, I also don’t want to come home to a pinhole leak.

      My county requires licenses to pull permits for plumbing and electrical. So I can’t pull permits. But compared to the dingbats who obviously had licenses and pulled permits to do substandard copper work in my house (they made some very poor choices in some places), I’m a damned artist.

      Their work got approved, so I put NO faith in the inspection process in my county. Even the few things I’ve had done with permits and professionals were cursory glances at the installations with one or two comments to sound like they knew what they were doing. Maybe they do and just don’t care as long as it’s safe…

      They did see my upgrades and wanted to know who did the work. I told them I did it. They didn’t give me any trouble, and actually asked if I worked as a plumber for a living.

      Still, as pointed out in the article, these sites and youtube channels are great sources of information.

  2. The HVAC landscape is a fascinating clash of DIY, hacks and mindless union drones. I recently installed an HRV unit (Venmar 225) and immediately filled it with temperature sensors. Then I looked at the controls to determine how to control the unit with my own system. The 250 model apparently has remote low speed control. Not the 225. But I’m guessing the board is the same – just the 250 came with a better remote.

    The wiring of the 250 is just :Yellow to Yellow, Red to Red, Green to Green, Black to Black. I have yet to find any intelligent spec sheet indicating which line is power, data, control, ground, latte, launch nukes, etc.

    I even called Venmar. Nope. Proprietary digital signals. “It will only work with their controller”. They wouldn’t provide any useful information. I’m not buying their controller. I want to use my own.

    I’ll figure it out eventually. But my experience has been that the HVAC industry really doesn’t like anyone on the job site thinking. Just swap the part and leave the thinking to the engineers back home.

    1. That type of thinking is infecting any number of technical domains. I call it ‘Three-ring binder” managment and I pity kids going into the licenced trades that will have to live with it.

      1. Seems the HRV industry is following the automotive industry in trying to create locked in proprietary systems. I can only hope that the market will eventually convince them to standardize on controls (that make sense). In the meantime, there are no good generic HRV controls available and if you have to replace the main unit, you’ll probably need to replace the the controls too.

    2. I also installed an HRV after my own improvements of replacing all windows and doors (spray foam and soft flashing) and spray foaming the rim joists sealed up the house and caused high moisture in the winter months.

      The HRV fixed that right up. But like you, when connecting it to a smart thermostat that can control HRV, heat, AC, etc, it runs the HRV fans at full speed. It would be nice if this was also controlled by the thermostat but alas it seems like on or off are the only options.

      1. Mine has a local button that cycles Off/Low/High (in Off or Low the remote overrides and runs the unit at high).
        Once the warranty runs out later this year, I’ll be looking at how I can build a remote that (intelligently) cycles through those states to give the illusion of a remote low speed control.

  3. My favorite part of this post was the insight into what made someone a hacker – fascination with a system and a desire for knowledge. I know that my own love of vacuum tube gear is due to the glow (and smell!) of an antique tube radio we had in the house when I was a kid.

  4. Q: “Can I fix this myself?”
    A: Sure. Go ahead. Just be aware that you can be fined $20k for venting refrigerant to the atmosphere. Yes, it is unlikely you’ll be caught or reported, but it seems like an expensive and embarrassing mistake to make.

    It can be a brutal job with some of the worst conditions. Hot in the summer doesn’t come close to describing 100F+ temps in attics or sub zero temps on freezer calls.

    But man the money and respect is good. I would wholeheartedly recommend the trade to anyone who loves challenging work and problem solving while having one foot in the future and one in the past.

    1. That fine is a common piece of FUD that people who don’t want others working on their own systems use to discourage them, and you’re right about it being unlikely. All you have to do to eliminate virtually any possibility of being fined (which BTW is up to $37,500 per occurrence per day now) is obtain the proper certification (easy, quick, and cheap multiple choice test) and recover used refrigerant instead of venting it. De minimis and accidental releases aren’t illegal, so you have to actively do something stupid on purpose to risk getting fined. And if you don’t want to go to the trouble of buying recovery equipment and hauling your used refrigerant off for proper disposal, you can always bite the bullet and pay someone else to come out just to do the recovery for you.

      But let’s play devil’s advocate for fun and assume hypothetically that you are the sort of deviant who doesn’t care for laws or the environment and vents refrigerant whenever and wherever you please. To end up on the EPA’s radar as an individual working on your own system, you would almost have to video yourself venting refrigerant while explaining exactly what you are doing and then mail it to the EPA with a letter fully admitting your guilt and daring them to come get you.

      But there’s a reward for turning in violators of *up to* $10,000 you say? What if a nosy neighbor who needs money and doesn’t like you secretly videos you through the slats of their 2nd story window venting away next to your condenser and mails that video off to the EPA?

      How would they tell what you were venting from such a video? Maybe you were venting a nitrogen test charge. Maybe your system was charged with propane (R290) and that’s all you were venting. Propane should never be used in occupied spaces or in vehicles as refrigerant because of its high flammability, but that doesn’t stop everyone. Propane does, however, have excellent properties as a refrigerant aside from its flammability, and it’s legal to vent. Without a confession from you, that video would almost certainly be next to worthless.

      The only time the EPA has gone after an individual for venting refrigerant in recent memory that I know of is a case where a convicted copper thief cut line sets while stealing condensing units. I believe he actually got jail time over that, but it was served concurrently with his time for burglary.

      I’m not a lawyer, but I’d be more worried about racking up $37,500 in parking tickets somehow than the EPA.

  5. I used to work in HVAC for a living. Working in 150°F and above attics, exploding circuit breakers, 110V AC lines shorted giving 220V AC, getting hit with 460V 3 phase AC (That hurt like a mother f#%&er), freon lines exploding because they can’t handle the pressure of R134A, the list goes on of shit I’ve seen and done. My favorite was a camper that the thermostat went out on at a build site. Until a replacement could be found I hacked it with a few switches to get the system working leaving instructions to cycle the AC compressor every so often to prevent it from freezing up. Good times I sorely miss.

    1. I had that song from Brazil stuck in my head since I read the headline and saw the artwork at the top of the article. Thanks to this clip, it will be in there all night. Thanks.

  6. I’ve been in the trades (not hvac but electrical) for 19 years now and I still love my job. One reason I still love it it because it is still challenging. Every day is a new adventure, with a new puzzle to put together or a new problem to solve. I get a kick out of homeowners who want to watch you to learn, that’s all fine and dandy but when I ask how I know how to do this or that I tell them, after you’ve worked 30,000 hours in a field you pick up a few tricks. And when they say I made something look easy I just ask them to please not ask me to do their plumbing for them because in that field I’m probably just like them and will make 4 trips to a box store and still have all the wrong parts.
    It’s really hard to describe to people how you knew what to look for on a particular service call or how you came up with an idea to make a designers vision come true when you’ve been immersed in a trade so long. I can now talk through pretty complex problems with homeowners over the phone to see if we can get them going without a trip out. On the flip side there are still things that stump me and I have to sit back and really dive into it to figure out what is going wrong or how to accomplish the desired outcome. I’ve found that if you are willing to spend the time, are able to not get flustered, and the homeowner isn’t panicking about the bill, there is nothing you can’t solve.
    Also, a close second of why I love my job (as I work primarily in the residential remodel field), I get to meet families, help them through a problem or build a piece of their dream, and build relationships with them every day, and I find immeasurable job satisfaction in that.

  7. I apologize in advance for the length of the following rant, but I feel the need to vent about the current state of HVAC technology and the anti-consumer nature of the business. After several unpleasant experiences with HVAC contractors, HVAC has become a bit of a hobby of mine.

    HVAC equipment manufacturers, supply houses, contractors, and technicians tend to be overly protective of their trade. Some online HVAC communities are downright hostile toward DIYers, homeowners (a term they often use in a pejorative sense), and hacker types. HVAC-Talk is one such place.

    HVAC-Talk has a special “professional” membership for forum members who have provided evidence that they are involved in the trade. If you go there and ask a technical or pricing question without having a professional membership, your thread or post will likely be deleted or locked because those questions from a non-professional member are against the rules. Professional members have access to private forums where technical and pricing discussions are welcome among insiders.

    HVAC-Talk allows non-professional members to ask questions that aren’t very technical and not about pricing in their AOP (ask our pros or something) forum, but they’ll shut you down as soon as they get any clue that you might be interested in doing something on your own. The AOP forum is basically a joke. They might give you basic advice on topics such as operating your thermostat or choosing a contractor, but that’s about the extent of it.

    They’ll tell you that these policies are for your safety and to protect them from liability, but I don’t buy it. Sure, HVAC work can be dangerous, but there are lots of sites that deal in dangerous things (e.g. Hackaday). And I’m not aware of too many successful lawsuits over information regarding dangerous things gleaned from a Web site. The real reason for these policies is, of course, to keep you stupid. They’d rather you pay one of them instead of doing something on your own. And they’d rather you didn’t have a clue about how much parts cost so that they can continue to charge their absurd markups.

    Most of the HVAC equipment manufacturers try to keep tight control over their distribution channels. They void warranties for equipment purchased or installed by end users who aren’t contractors. They mostly only sell to distributors and supply houses who are often not keen on selling to DIYers. One notable exception to this is Goodman. Even though Goodman, like the other guys, won’t honor warranties on equipment not installed by a licensed contractor, they at least don’t try to prevent their equipment from being sold online at reasonable prices to anyone who wants to buy it. And despite what anyone says, Goodman equipment is comparable to all the others.

    HVAC supply houses run the gamut. Some of them are true capitalists who will cheerfully sell to anyone who walks through the door and at reasonable prices─God bless them. Some of them will sell to outsiders at trumped up retail prices, which could be double, quadruple, or more than what a contractor would pay. Some of them wouldn’t be caught dead selling anything to an outsider for fear that one of their bread-and-butter contractor customers might find out and boycott them. It’s interesting to observe that even the snobby supply houses will start taking all the business they can get during severe recessions. Most supply houses will tell DIYers that there are no warranties or returns allowed, which I can understand and live with.

    In terms of taking advantage of customers, I put HVAC contractors right up there with car dealerships, hospitals, and veterinarians. People tend to call these folks out to fix a non-functioning system during extreme hot or cold weather, and they know they’ve got you by the balls. Their latest trick is flat-rate pricing. Instead of quoting you a parts cost and an hourly labor rate, they offer you one price to do the job. They’ll tell you it’s simpler and less confusing, but the real reason they do it is to obscure the ridiculous prices they are charging. These flat-rate prices are often high enough to account for a 3x or 4x parts markup and an hourly labor rate in the hundreds of dollars. They know people would tell them to get lost if they itemized that kind of labor rate. If an HVAC contractor insists on flat-rate pricing, don’t even ask how much. Just run.

    I decided enough was enough a few years ago after a supposedly reputable contractor took advantage of me on a hot summer day because my split system air conditioner wasn’t working after losing a sufficient amount of refrigerant from a leaking evaporator coil. Those slimy profiteers charged me around $100 per pound of R22 plus a service call fee. This is when R22 was selling for $10 a pound (around $13 currently) wholesale. I knew it was a ripoff, but I went ahead and paid it because I needed the system working that day. They also offered to replace a good (I measured only 50 mV across it just the other day) contactor (well under $15 shipped to your door on eBay and a 15-minute job) and a good blower motor (still going strong to this day) for $600. That blower motor is just a commodity ½-HP PSC ($50 wholesale?) one that takes about 30 minutes to replace. They also offered to replace the system (4-ton A/C and 100,000 BTU furnace) with a contractor grade 13-SEER condenser & 80% efficiency furnace for over $7,000! I went and got my EPA sections 609 and 608 universal certifications soon after that.

    That was not an isolated experience either. I’ve previously had similar experiences with other HVAC contractors. They all want to charge a super premium price whether they do good or inferior work. I’ve seen all sorts of inferior work done by so-called licensed “professionals” (butchered and burned cabinets, pinched line sets, mismatched coils, code violations, you name it), and they often do it without getting the required permits. Many of them will do just about anything to finish the job faster so they can work in an extra job for the day.

    I understand these guys need to cover their expenses and deserve to make a fair profit, but the prices many of them charge are just unreasonable and predatory.

    As far as technology goes, not much has changed in the last half century of vapor compression cooling or with gas furnaces. Multi-stage furnaces with high-efficiency condensing heat exchangers are becoming common now. Inshot burners were a big advancement a couple decades ago. Getting rid of standing pilots was also a welcome change. Refrigerants change every few decades because of environmental concerns. PSC motors are still the norm for blowers and in hermetically sealed compressors for residential applications, but electronically commutated blower motors are appearing on the scene now. ECM motors are the future, but they’re still incredibly expensive. Expect to pay over $1,000 to have one replaced, and good luck replacing one on your own because the ECM controllers often need to be programed by a distributor or manufacturer using special equipment for a given furnace or air handler.

    Most of the electronics in HVAC systems are still dirt simple by today’s standards. All you’ll find in a typical residential condensing unit is a contactor and run capacitors (to give your motors that skookum phase shift they need to chooch) for the blower motor and compressor. I think integrated furnace controls have finally mostly abandoned through-hole construction and multiple discrete ICs. Flame rectification is an interesting technique used by modern gas furnaces for proving ignition. Furnaces typically have several simple limit switches for preventing unsafe conditions, which is comforting. The electronics and software in a Nest thermostat are far more advanced than in any other part of a modern system, not that you want or need that kind of complexity in safety critical parts of the system.

    The good news is that the Internet has leveled the playing field a lot for DIYers in recent years. You can find lots of reasonably priced parts on eBay and other sites now. Specialized HVAC tools have also become more available and reasonably priced. Refrigerant recovery used to be a big barrier to DIY work, but you can buy a refrigerant recovery system online suitable for most any residential work for under $400 these days. Finding a place to accept your recovered refrigerant for recycling as a DIYer can still be a hassle though. And look out for the steep fees they’ll nail you with if you turn in contaminated or mixed refrigerant. Armed with the right knowledge, you can probably buy all the tools you need to handle any residential HVAC job for $2,000 to $3,000 nowadays. You don’t have to avoid many calls to a contractor to pay for that. One system replacement can easily pay for it.

    Most of the equipment manufacturers still try to keep their technical documents out of the hands of DIYers, but most of it is out there if you know where to look. Fundamental information is out there too and pretty readily available now. YouTube is fantastic for how-to videos of course. An understanding of basic thermodynamics and reading an HVAC textbook are good places to start. I certainly don’t recommend poking around HVAC systems without having confidence that you can do it safely. If you don’t know what you’re doing or lack the proper tools, you could end up with severe frostbite, being electrocuted, burned, killing building occupants with carbon monoxide, burning your house down, or causing several other catastrophes. But then again aren’t these the usual kinds of hazards projects highlighted by Hackaday present?

    HVAC systems are certainly interesting from an engineering perspective. You’ve got interesting thermodynamics, fluid dynamics, electronics, and all sorts of physics happening in one system under your roof. It’s easy to see why hackers and engineers would find the systems interesting, but we need to get away from archaic vapor compression cooling. Today’s systems are inherently unreliable, complex, and expensive. Reliable and practical solid state systems are likely decades away, but HVAC contractors may see their repair business go the way of TV and VCR repair when it happens.

    Lastly, please don’t be upset with me if you are a good and honorable member of the HVAC industry. I do know you’re out there.

    1. Tldr; but agree that the HVAC community is closed off to ‘non professionals’ in the name of ‘safety’ and ‘litigation’ when much more dangerous info is online without issue. It must be to protect the financial interests of the tradesmen.

      All I needed was some advice on which part to get an engineer to replace. All my threads were closed with ‘hire a good engineer’.

      How many call out charges am I supposed to pay hunting down this elusive ‘good engineer’?

    2. I read through most of what you wrote and am saddened by what you had to endure, I am one of those honorable persons that started in hvac work, but have transitioned over to appliances and commercial restaurant equipment work. there has been a shortage of QUALIFIED service techs for quite a while and this goes hand in hand with the experiences you have had with apparently unqualified ones.

      I will still work on hvac but lack employees to fill the needs of an installation crew, so I have had to turn down requests to do so, I refer them to a local team that I have seen and know they do good work. I will also sell equipment to select individuals who have demonstrated they have the now how to do the installation themselves.

      I sell appliance parts direct to people who can demonstrate the skills to do the job. Most contractors would call me crazy to do that, I call it searching for employees. it has yet to yield results as most people who have the intelligence to do the job, demand a pay scale higher than what I pay myself and we cant afford based on the local economy.

      It’s not the technicians at fault for their lack of knowledge, it’s their employers that don’t, or can’t, pay enough. at this point, all i can do is ride it out and hope inspire some local high school students to get into this trade, but it’s not for everyone.

      But what qualifies a person to work on a furnace? better yet, lets look at what happened to the automotive industry when the OBD came out. They were more expensive and it was just a tool that helped qualified techs get to the finish line faster. now you can get one cheap and fix it yourself. but having an OBD doesn’t automatically qualify you as a tech, having the know how does. The hvac industry is currently trying to enact an OBD code system for itself and a universal reader to help. this is a mistake since like cars, you need to be qualified and knowledgeable in the field to make sense of the information.

      This may seem like a harsh statement, but I am in the hvac industry, I am not an auto-mechanic, I dont pretend to be, I have those who are work on my car just as I expect to be called when I am needed to work on a furnace or air conditioner. my prices are reasonable and I refuse to screw a customer just because I can. My first job is to be a decent human being, I value a good nights sleep.

    3. Pieces of my washing machine are scattered around my garage like acorns under an oak tree. What started with a leaky drain hose is now a disassembly to repair 20 year old finishes, and replace worn plastic parts. The parts are widely available. The wiring diagram is on the cabinet.

      Last month I repaired the heat pump. After 6 years in our hot humid air, one of the 220VAC terminals at the air handler fan motor connector was corroded. Again, the parts are widely available, and the wiring diagram is on the cabinet.

      This washing machine, and heat pump, were sold with no intention by the manufacturers to withhold service information, tools, or parts.

      Now a car example: 2004 Volvo. Low fuel pressure cause was isolated to the pressure sensor in the fuel rail. I was able to read non-OBD codes, and display real time data, with a bootlegged device between the car and laptop (thank you hackers). To do this legally, one must send thousands of dollars _per year_ to Volvo. While there is usually some self serving justification (liability, safety), the intent is clear: withhold service tools/information/parts from the car owner to provide continuing income. With strong ecryption, and the DMCA, hacking current cars is all but impossible. (Which car manufacturer is currently best for owners who do their own repairs?)

      I research my purchases thoroughly. My priorities in order are: functional, durable, repairable, beautiful. I view every purchase as a vote for the manufacturer. I passed on buying a well designed blender because the manufacturer, Vitamix, withholds service information and parts. No kidding–a blender!

      Instead of the simple single speed heat pump repaired above, I would have bought Mitsubishi mini-splits if the manufacturer didn’t withold service information/tools/parts. In my climate, paying “factory authorized service technicians” to troubleshoot the inevitable corroded connections, and lightning damaged semiconductors, would not be economical. The wiring diagram is not sufficient anymore; one must be able to communicate with the computer.

      I enjoy repairing all the crazy things humans have built from stuff found on this earth. As a curious engineer with decades of hands-on experience, this trend is terribly frustrating.

  8. Regarding the elimination of standing pilots in residential HVAC equipment being welcome, I began working before California outlawed them for HVAC ( water heaters not included) and as with everything else California’s standard is what the remaining states adapt invariably be it automotive or CPS, California sets the standards.
    Prior to 1978 a gas furnace was a reliable sturdy piece of equipment often 30 + years old and that most can repair with parts available at a hardware store just as with water heaters to this day you can buy a thermocouple and replace it simply, they rarely fail and we often never think about them for decades.
    When furnaces began using intermittent pilots that meant spark or hot surface ignitions which meant expensive ignition modules or circuit boards, ignition proving devices, flame sensors etc , all prone to failure about every 7 years and with the pursuit of economy they began extracting so much heat from the units they could no longer vent normally thus requiring induced draft motors,assemblies, controls and proving devices such as pressure switches or sail switches, all expensive delicate and requiring maintenance for continued operation, we now have flimsy fragile expensive equipment that requires regular servicing to continue operating reliably.
    I removed hundreds of allegedly “outdated” furnaces from underneath homes that were beautiful i many cases, built in town by a long gone shop out of heavy cast iron that lasted decades, resembling a metal octopuses with it’s main body and tentacles / ducts that allowed the heat to rise naturally with no need for any fan motor to blow the air or induce a draft for combustion, the gas valves were millivolt type ,powered by a thermocouple or pilot generator impinging upon the pilot flame , no need for power get heat, in a power outage they worked perfectly silently ,80% efficiently and lasted for a lifetime.
    I kept the data plates from some of the nicer units that were built by shops in town , long gone.
    If I had left those units in place in the 1980’s and 1990’s I have no doubt they would be still operating today maybe without any need for service, I promise you no matter how good the replacement equipment was today it is probably in a junk yard and been replaced already but not before costing several thousand in maintenance’s and repairs before replacement for another more “efficient” unit that has variable speed DC motors that can run on a 9 volt battery an in fact use them in troubleshooting there motors and cost $1,500 compared to the PSC motors that cost less than $100, usually less.
    If I had a millivolt furnace I would never remove it. Maybe 10 million pilot lights cumulatively make a significant impact but individually I say the loss of standing pilots for HVAC equipment has been a boom for the contractors but an expense to the homeowners.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.