Another look at "Waste Not" radiant design.

In the September 1996 edition of PM we ran a feature article about Aztec Radiant Heating title "The 'Waste Not' System Designers," bylined by Jim Olsztynski and Dan Holohan, who collaborated on the coverage and writing. The point was made in that article that the designs and techniques used by Aztec's father - son owners Elwin and Bruce Maur were unconventional, even controversial.

How prophetic! Soon after the article was published, we received a scathing letter from Mark Eatherton, a radiant/hydronics contractor from the same Rocky Mountain area, taking on the owners and their techniques.

It has always been PM's policy to air all points of view, usually in our Letters section. In this case the technical subject matter was rather complicated and the criticism harsher than usual. We didn't feel comfortable treating it as a casual letter to the editor; nor did we want to publish it without giving the Maurs a chance to respond to the attacks against them. We also invited Dan Holohan, who knows and respects Eatherton and the Mauers alike, to contribute an informed third-party perspective, which follows their presentations.

So with all parties consenting, what follows is a freewheeling exchange of views from which we think the entire hydronics industry can benefit. For full understanding, serious "Wet Heads" may wish to give the original article from the September issue a read or reread before plunging into this debate.


"Aztec's 'Appalling' Installations"
by Mark Eatherton
Radiant Floors Inc., Denver, Colo. I am a long-time reader with over 19 years in the plumbing /hydronics field. I believe in your publication so much that it is required reading for my Advanced Hydronic Heating course that I teach at a community college here in Denver.

To my great shock and dismay, right there between the covers of my most covered journal, was an article by my two favorite writers on Aztec's self-confessed "appalling" installations. Having seen Aztec's work and having spoken to numerous of their disgruntled customers, I can tell you that they have and currently are setting up the radiant panel industry for MAJOR failure that will give the industry a black eye for decades to come.

The problem has already come home to roost. We nearly lost a recent bid on an 8,000 sq. ft. home because of one Aztec's "appalling" systems. The prospective home owner visited with one of her friends who had an Aztec system installed. When how she liked her radiant heating system, the home owner stated that it did not work when it got below 40 degrees outside, that her utility bills were extremely high, and that she would not recommend radiant heat to anyone. To boot, she had to go to a local restaurant in order to get a cold glass of water. (So much for eliminating the expansion tank and backflow prevention!)

OK, I'll give them the benefit of the doubt. Maybe they, were like so many other contractors who weren't aware of the oxygen diffusion problem as it related to ferrous parts. But when told by manufacturers representatives that the tubing that you are using is not recommended for long-term circulation in oxygenated, hot, potable water applications, should this recommendation be ignored? What's going to happen t those million - dollar - plus homes when the PB tubing becomes brittle and begins cracking?

I can tell you what will happen. This industry is going to suffer a large black eye from which we will probably never recover. Remember, one dissatisfied customer tells 10 people of their bad experience, and those 10 tell 10 others, and so on.

Efficiency? In one of the photographs, I count 13 large pumps. If my eyes are not failing me, those pumps are Grundfos 4075s, and I know that they consume 225 watts per hour. I'm heating 10,000+ sq. ft. homes with 185 watts worth of pumping power. Does Aztec understand hydraulic flow dynamics? It is obvious thermal dynamics.

We've got rectangular houses with 30-foot ceilings at an altitude higher than Evergreen, and we don't have any problems heating them. Of course, our tubing is on the INSIDE of the house under a layer of gypsum. Does Aztec understand that radiant panels heat bodies and not air? Obviously not.

And talk about a waste of tubing, our systems are typically 12 inches on center. Does Aztec think installing tube 8 inches on center is a wiser use of our precious resources? Does Aztec know that their "high efficiency boilers" will only deliver 56 percent of their rated sea level rate input at 9,000 ft. elevation?

By the way, 56,000 Btu divided by 3,600 sq. ft. equals 16 Btu per square foot per hour. Maybe now I know why their heating systems don't work near design conditions. If their work is so great, why were they not asked to perform their wonderful work on phases two and three of the retirement village?

Mr. Mauer, do this industry a favor and either shape up or ship out. We do not need your type helping us along.


"Pushing The Leading Edge"
by Bruce and Elwin Maur
Aztec Radiant Heating, Evergreen, Colo. We appreciate the opportunity to respond. Our main concern in the reference to "numerous of their disgruntled customers," and a home owner stating that our system did not work below 40 degrees with extremely high utility bills.

We are not perfect and are known for our willingness to push the leading edge of radiant heating. A few of our systems have not initially worked as intended. Most of the systems that we have had to put extra dollars into (usually Aztec's) were attributable to the agreed to by owner.

We know of only one job that is not performing and it is a special case. The architect/builder used a new building technique that was claimed to have an R value of 40, which is how we designed and bid the job. The actual R value was realistically R5 toR8. Even before the job was completed, the architect/builder ran thousands of dollars over budget and had gone belly up, owing us thousands of dollars after we had put in many extras at our own expense.

The owner was an attorney who had circumvented the lien system and flatly stated he was not going to pay us (at the time systems performance was not an issue). We took the homeowner and architect/builder to small claims court and lost because our contact was with the now bankrupt a/b, and the homeowner had no responsibility to us. When the system needed adjustments and wasn't working as it was supposed to, we told the owner to work through his architect/builder, who had moved out of town. The best solution to this job was to have added insulation to bring it up to design. As for high fuel bills, the boiler probably never shut off during cold weather.

Our business is based almost entirely on customer referrals. This and one other are the only disgruntled clients that we know of out of some 200 systems. Nobody wins in these situations, but they do happen.

Radiant is the most efficient delivery method for heating. Aztec uses a 94 percent efficient boiler/hot water heater, the most efficient now available. But heat loss is heat loss and if the contractor doesn't insulate at least the perimeter of the foundation and slab, or has large expanses of glass and doesn't seal for air infiltration, there will be additional fuel cost.

The rest of this "gentleman's" letters refers to problems that don't really exist:

  • We "weren't aware of the oxygen diffusion problem as it related to ferrous parts," We have been aware of this problem since 1984 and the article said so. We have used NO ferrous components in our systems since 1985! Hence the reluctance to use steel expansion tanks and cast iron water valves. We do use bronze back flow preventers and domestic water expansion tanks where required.
  • As to the breakdown of PB due to oxygen: This gentleman is mistaken in his belief that the oxygen barrier is there to protect the pipe. It is there to allow contractors to use steel or iron components in their systems.
    He may be referring to a graph used to sell PEX pipe. This graph is based on a water temperature of 200 degrees. This temperature was chosen to make PB look its worst and their pipe its best. If the temperature is dropped to 140 degrees, it significantly changes these graphs. We refer you to the APTF II Data and Analysis. Even the worst case expected life span of 55 years concerned us, and we are including outdoor reset in our basic systems to reduce the temperature further and provide greater comfort and longevity.

  • The pumps in the photograph are Grundfos UP43-75BF, not 4075s, and they use 215 watts, not 225. He was wrong in assuming they were used in a single- family dwelling.
    This was an 80,000 sq. ft. - plus project that we opted to break down into about 3,000 sq. ft. pods with a separate pump for each pod. We did this to facilitate maintenance and minimize electrical consumption. This also added flexibility and redundancy to the job. Instead of one or two huge pumps running to satisfy just a few zones, only one small pump is needed. Only in the most extreme weather will most or all of these pumps be operating. Aztec was also limited to this pump because of the project engineer and the distances that needed to be covered.
    I do take exception to his use of a 185-watt pump to heat a 10,000 sq. ft. home. He needs to check his supply vs. return temperature. By using a slightly larger pump (245 watts for the Grundfos UP26-99BF), you can significantly increase the velocity through the pipes and provide a more consistent temperature gradient, adding to both performance and comfort.

  • In reference to Aztec using more pipe: There are tradeoffs. We do use more pipe, but we provide quicker response time, higher efficiency, less initial cost and we don't use the additional resources required to enable the use of Gyp-Crete, like a beefed-up structure, nailers for wood floors, extra plate and of course the Gyp-Crete itself.

  • In reference to de-rating our boilers: Yes, we do de-rate for altitude and our "high efficiency boilers" are still high efficiency. They still operate at 94 percent but their output is less. Just like a car's mileage doesn't change from sea level to the mountains, but the power drops.

  • "Why were they not asked to perform their wonderful work on phases two and three of the retirement village?" Bottom line, a competitor used scare tactics and promised what he could not deliver.
We have been asked to bid on the next phases of this project. We are also interested in comparing the efficiency and performance of our phase I and II (one building) with our competitor's phase III and IV (an identical building). We believe the owners are doing the same.

Aztec was taken aback by the vehemence of the letter. We take pride in our systems, do our research, test theories and attend all the classes and seminars we can. We fear that this "teacher," who appears to be very opinionated and set in his ways, may have run into one Aztec's systems on a service call and found himself totally lost.

by Dan Holohan

Mark Eatherton is one of the brightest and most passionate Wet Heads I know working anywhere in the world, let alone the Rockies. I've been on his jobs (they're gorgeous), and I've spoken to his heating students at Red Rocks College (they give me much hope for the future). I've shared a meal with him, enjoyed his company, and benefited from his insights. I know where he stands on hydronics issues, so I knew the Aztec story would probably get his knickers in a knot. Considering his passion for excellence, I would expect nothing less from him.

Radiantly speaking, the Mauers don't do things the way most folks do. They bend rules, experiment and often aggravate competitors. But they also feel passionately about what they're doing. I shared a meal with them, and I also enjoyed their company and benefited from their insights - radical as they may seem.

Jim Olsztynski and I knew what we were getting into when we wrote this story. We knew it would be a lightning rod because it was about radiant heating - and because it featured a company that wasn't following the rules. That, we thought, was what would make it an interesting story. We hoped our readers would consider Aztec's unorthodox approach to radiant, and then decide for themselves whether Aztec was right or wrong.

PM has always been a place where people can go have their voices heard. It's always been a lightning rod. That's one of the reasons why I enjoy writing for them. I enjoy a good conversation, especially when it gets a bit heated.

There's one thing of which I'm fairly certain, though. The Mauers don't have the power to single-handedly destroy the radiant heat industry by their installation methods or choice of products. No one's that strong.

Over the years, I've had people point a finger like the Grim Reaper and warn me off certain products and installation techniques. "Do that," they cautioned, "and you will be the cause of the demise of the hydronics industry."

These warnings have revolved around low-mass boilers (they waste energy and fail quickly), copper tubing and grooved fittings (they'll be the death of the working man), plastic pipe and rubber tubing (bury that junk and watch what happens in 10 years), oxygen-diffusion corrosion (every radiant job you install will fail, you'll see), service valves (home owners will do the work themselves), water lubricated circulators (they'll get stuck every fall), electronic controls (this stuff is too spooky - give me electromagnetics), supply side pumping (that's not the way my father did it!), staple-up radiant (it can't possibly work!), European products (you'll never find the parts), and on and on.

It seems that every advance in technology, every variation in installation methods, every attempt at something other than the norm drives someone nuts. But you know what? If we didn't have people who push the limits and try things, we'd still be heating with stoves.

To me, the essence of change is experimentation, and experimentation is the engine that pushes us to the next level. I think it's good to throw all the ideas and opinions - as radical as they may seem - on the table for discussion. And I think we can rest assured that the hydronics industry is strong enough - and, I hope, tolerant enough - to survive the "heresy" of the Mauer family, if that indeed is what it turns out to be.