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It’s been nearly 30 years since John Siegenthaler’s “Modern Hydronic Heating” was first published. In 1995 to be exact. The word “modern” belonged in the title because, at the time, it was on the cutting-edge of hydronic heating technology.
In its 449 pages, there isn’t one mention of modulating condensing boilers (only condensing), dirt separation, magnetic separation, air separation, hydraulic separation, ECM circulators, press technology, water quality or condensate neutralizers.
Some of the terminology was different back then and the others weren’t a thing yet. Microbubble resorbers were mentioned, but not specifically as air separation; the same can be said for hydraulic separation. In the first edition, it was explained as primary-secondary piping with the use of closely spaced tees. Some of the older terms are still interchangeable with today’s terms.
The World Wide Web was in its infancy; most of us saw an AOL yellow figure of a human being running as our dial-up service took forever to connect. It seems like yesterday and 100 years ago at the same time.
This was right about the time my business shifted exclusively to hydronic heating, so you can bet the farm I bought a copy of Siggy’s first edition of “Modern Hydronic Heating.” John was even kind enough to sign it for me. He’s a smart guy and a nice guy to boot. As the letters following John’s name indicate, he is a professional engineer — one who specializes in hydronic heating. We all should be thankful for it.
John, in keeping with new technology and products, gave us 575 pages in the second edition in 2004, followed by the third edition in 2011. Now, 2011 does not seem that long ago to me, but the following paragraphs will give you an idea of how far we’ve come as an industry in 10 years.
Last April, John’s fourth edition of “Modern Hydronic Heating” was published. I was fortunate enough to get my hands on a copy quickly. This book adds more than 130 pages of new material, topping out at a whopping 867 pages. It’s shorter than “War and Peace” or “The Lord of The Rings,” but for this boiler guy, it’s a hell of a lot more interesting.
I’m writing this in late April, and I’ve already flipped through every page in the book at least twice, making mental notes along the way of what’s new, what needs to be reread and what must be read for the first time. In the book’s preface, John makes clear what his intentions are:
“Over the last four decades, I’ve had the opportunity to see both ends of the design and installation spectrum. From systems that are ‘textbook examples’ of proper design and consummate craftsmanship to multi-thousand-dollar assemblies of hardware that will never deliver what is expected of them. One of the consistent differences between these successes and failures has been a commitment by the designer/installer to go beyond joining [pipe] and turning wrenches, to learn the fundamental principles at work in every hydronic system.
"Since the third edition was released in 2011, there have been many new developments in the hardware and design concepts that now represent cutting-edge technology. This third edition reflects those changes. It emphasizes simplicity wherever possible, and conservative use of distribution energy to move heat through hydronic distribution systems.”
How’s that for a mission statement?
By page 17, Siggy is already talking about the importance of system design: “The objective is to achieve a stable, dependable, affordable and efficient overall system.”
Throughout the text, the narrative is consistent. You must have a proper design before you start assembling pipe, fittings, circulators, boilers, controls, etc. There’s equipment sizing by way of a heat loss load calculation, pipe sizing, pump selection by knowing its flow and head loss requirements, boiler selection, valves, air separators, magnetic/dirt separators, consideration of water quality, and the proper placement of each.
Renewable energy and decarbonization
In all four editions, chapters 2, 4 and 6 were always the most valuable for me, information meat and potatoes: “Space Heating and Domestic Water-Heating Loads,” “Fluid Flow in Piping” and "Hydronic Circulators," respectively.
But that has changed, as John points out:
“Interest in renewable energy and decarbonization has also grown exponentially since the release of the previous edition. A thorough examination of renewable energy heating systems reveals that hydronics technology is the ‘glue’ that holds nearly all these systems together.
“Although heat sources such as solar thermal collectors, air-to-water heat pumps and solid fuel boilers are the ‘engines’ of such systems, hydronic technology is the ‘drivetrain’ that delivers the heat when and where it’s needed. Without proper hydronic detailing, none of these renewable energy heat resources will perform up to their full potential.”
That’s it. This is why the fourth edition is so important to me. The technology in our industry is moving forward at a brisk pace and I want to move forward with it. The day I stop learning new things is the day I’m done. I’ve been a student of John’s since the mid-’90s, so this will be no different. Those three systems mentioned previously, along with hydronic cooling, are the reasons I’m all-in on this, so let’s look at some of them.
When you’ve spent the entirety of your career fieldwork in Chicago and its surrounding communities, your phone will not be lighting up because somebody wants an estimate on a wood-burning boiler or a pellet boiler. I know mine wasn’t. The only constant in life is change; when I switched from hydronic contractor to hydronic designer and moved to Vegas, the types of requests changed.
It wasn’t only people from metro Chicago that I was working for anymore. It was systems over the entire United States and Canada now. I turned down design opportunities because, quite simply, I didn’t know enough because there wasn’t a need before. This book will be the start of that change.
Same goes for solar hydronic heating. Every third house out here has solar panels on its roof. Ours does not, but we do have a hydronic system in which I can incorporate them.
Chapter 15 is where this edition really shines, “The Fundamentals of Hydronic Cooling.” Forty-two pages of entirely new content. I read it all with my yellow Sharpie highlighter in hand; by the second page of the chapter, I was using a red pen to highlight the best of the highlights. I’m not kidding. By the time I finished, both writing utensils were running on fumes.
Here's the first thing I had to reread to make sure I got it right:
A 3/4-inch tube carrying chilled water at a flow rate of 6 gallons/minute through a hydronic cooling circuit that absorbs enough heat to warm the water by 15° F is conveying 45,000 BTU/hr.
I’ve known for a long time that water absorbs some 3,500 times more heat than air, but this is the first time I’ve seen it applied to something other than hydronic heating. I could sell these systems based on that fact alone. This is a sampling of the things we can learn in this chapter alone:
• As mentioned previously, a minimally invasive system: 3/4-inch pipe vs. 18-inch diameter duct.
• Reduced energy use and some simple equations to prove it.
• Available sources for chilled-water systems, including reversible heat pumps, dedicated heat pumps, water-to-water heat pumps and air-to-water heat pumps.
• Offers the same flexible zoning options as hydronic heating does.
• No more frozen coils.
• Options for hydronic cooling delivery.
• Very low refrigerant volume and its benefits.
• Thermodynamic concepts in hydronic cooling.
• Psychometrics 101.
• Chilled-water sources deeper dive, including lake-source cooling.
• Radiant panel cooling and the importance of chilled-water temperature compared to the dew point temperature.
• The importance of pipe insulation.
• I counted 15 different piping diagrams in this chapter, 26 photos and loads of charts that will be helpful to you if you’re a visual learner as I tend to be.
This book is a treasure and my new go-to resource because it’s going to teach me so many things I do not know enough about. It allows me to offer potential customers new and better options, resulting in more sales. My various collections of vinyl records, books and tools aren’t going to grow without those sales.
These are options readily available to us and are something we should be using more of. But as Siggy has always said, and I’m paraphrasing, you can’t assemble a bunch of pipe, fittings and components and assume they’ll work without putting the work in before the first wrench is lifted. For me, there aren’t many things more invigorating than learning a new skill. “Modern Hydronic Heating,” Fourth Edition, is the gold standard of hydronic heating textbooks.
Am I suggesting you buy this book? Yes, absolutely.
Is it shameless shilling? Not a chance. I’m not wired for that kind of nonsense and I know the value of learning from others.