Domestic and radiant water in the same pipe?

michael_13

michael_13

\"open\" direct radiant system

I'm building a house on Cape Cod and wanted to run the pex tubing for the radiant heat myself to save some money, and the company I was getting my materials from, Radiantec, is touting what they call an open direct system, whereby a hot water heater as opposed to a boiler fires both the domestic and the heating water at the same time, and they basically follow the same loop--the water doesn't become stagnant because every time hot water is turned on, cold water replaces the hot water by way of the radiant tubing, thereby flushing it out.
this system is supposed to be incredibly efficient, wold be much cheaper to install, which is what I'm going for, but I'm not a plumber, I have no experience with this, and can't find a heating guy around here to whom this makes sense, although there's a certain lack of imagination around here.
anyone out there ever done a system like this? anyone have any big opinions?

John@Reliable_9

Michael, go to the search bar...........................

at the top of page and just type "Radiantec" you will find allot of info. Also click on some of the threads you find,it will "open" your mind why open systems are not what you want in your home I think. Be forewarned thier are allot of threads but worth reading all.

Dave Yates (PAH)

There's a huge difference between

imagination and common sense. Aside from the water becoming stagnant whenever you aren't running water, there are pressure loss issues directly related to friction losses x length of piping, which can create large pressure imbalances and scalding issues.

I'd listen to the heating contractors. They don't lack imagination - they understand cross-contamination and bacterial issues.

Study the issues raised regarding Legionella bacteria (use Google to research "hot water + Legionella") and find out what your pressure drop will be before making your decision. If you still feel an open-direct system makes sense, go ahead, but be aware you will need to include the information about potential health concerns to any future owners to CYA.

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ed wallace

open system

I had a conversation with a man from southeastern ma. last month who has an open radiant system that was having problems and would not listen to reason because the salesman is always right open systems dont make sense

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DanHolohan

And once you get the Search results

just click Show Thread to read the entire string. Thanks.

DaveGateway

Code

Is open radiant even allowed under code in MA? I doubt it.

Weezbo

long ago and far away in the dim regions of the dark ages...

people did stuff that seemed plausable some lived to regret it some didnt. so nowadays we have dedicated much stock in the value of their sacrifices and have developed codes to protect us from going the same way .... most guys here have licenses that require us to protect the Public as well as the specific consumer of our work.
... this means been there done that and moved forward with a surety not to go that direction again. it is a thing of maturity of sorts,no means no. no we dont reccommend drinking water out of a swamp you can heat with it and cool with it..drinking it nah that went out in the dark ages when people threw their sewage out the windows.....
...nowadays we use heat exchangers or seperately derived systems ,california and oregon i think have gone to the double walled heat exchangers reasons being numerous. Not the Least being Health and sanitation concerns. i gotta run off to pick up my three new taco pump blocks right now....however you will find a Host of very clear cut thoughts on this matter dating back decades .Thank God they nolonger let doctors cross contaminate whole populations in the operating rooms.

J.C.A._3

Keep this post alive till Sunday......

And ask Mr. Milne. (Chowda), He had a very interesting volley with the PHCC at their conference in November.

Dance, dance , dance.... The answer was kind of comical. JMHO, Chris

Dave Yates (PAH)

As we speak, he's

having a beer built for him! Lucky chowda head(G). Binding rules!

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Robert O'Connor_7

Michael...

Before you go spending your hard earned $$$$$, review the threads on this site as well as the RPA site. Just go to the bulletin board on the RPA and scroll down to the bottom and look up the (hop to) commentaries. The only way you should install is by isolating the boiler from the domestic water via a heat exchanger. Can you say Legionella?..Robert O'Connor/NJ

Kevin_in_Denver

Direct Radiant systems

This topic is probably the most controversial here on the Wall. The majority here definitely think the DHW should be isolated from the boiler loop. Consider this, however... there are some experienced, knowledgeable, competent heating contractors that are installing this type of system. These guys are saying that the systems are allowed by code in a lot of jurisdictions.

They don't even bother defending themselves here any more. In talking with and reading about them, it seems that they believe that the precautions they take are foolproof.

Conclusion? Research it heavily so you can make an informed decision for your particular application. But as many here have noted, that extra heat exchanger and pump aren't that expensive.

Wayco Wayne_2

It reminds me

of The Renesance(sp?). They began making plates out of Pewter but didn't know there was lead in the Pewter. They were trying to get past using wooden plates which were not healty. After using them for a while they began to get lead poisoning. They didn't know what was going on but people were falling into a coma for no apparent reason. Some were even mistaken for dead and buried alive. If they had an occaission to dig up a coffin they sometimes found horrific scratch marks on the lids. (Did they say "oops, my bad," when this happened?) This gave way to the practce of holding a "Wake" just in case the person wasn't dead, they would throw a party and see if the person would "Wake" up. They also got into the practice of running a string down to the coffin up through a tube in the ground and attaching it to a bell so if the person woke up he could ring the bell. Hence the expression "a dead ringer." Grieving members would sit in the graveyard at night after the burial waiting for the bell to ring. This was the "graveyard shift." I say if there is any chance at all of bacterial infection from open systems it is too much of a chance. The price of a flat plate heat exchanger and an extra circulator is a pittance against a possible health issue of serious consequence. WW

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Robert O'Connor_7

Kevin..

What guys are you talking about?..Robert O'Connor/NJ

Kevin_in_Denver

Aztec Radiant Systems

Aztec Radiant Systems, Evergreen, CO
Check out the controversy at PM Mag

http://www.pmmag.com/pm/cda/articleinformation/features/bnp__features__item/0,,7144,00+en-uss_01dbc.html

They are still doing a lot of business in CO, with no recorded deaths.

There's another guy in Boulder using Rinnai. He is definitely not a "naive contractor".

If I remember correctly, when I called Aztec two years ago, they turned down work in Denver. Anyone care to speculate why?

Dave Yates (PAH)

Show me the bodies

Ahhhhh, that old chestnut. There have been several documented CAP (community acquired pneumonia specifically linked to Legionella sero group #1) deaths. It has also been demonstrated in several studies that Legionella SG#1 not only thrive and survive in potable hot water systems, they amplify due to the more favorable growth conditions in warm water.

Now, the only argument I've seen from the pro-open system group that makes any sense, is the notion that the Legionella are already present & that, therefore, open systems won't affect the situation one way or the other. And, that almost makes sense - but only if you can believe the laws of science, physics and reproduction can all be suspended or separated from reality.

The bare bones fact is that open systems, by their very nature, can't help but be an amplifier. If they are an amplifier, then they degrade the potability of the water. If a device is added to a potable water system that degrades its quality, while not being an essential part of the potable hot water system, then that portion should be isolated or disconnected from the potable water.

Why don't open system proponents defend their positions here? I'd say it's because not one of them has yet to counter the evidence that points to open systems presenting a potentially deadly scenario. We asked for a smattering of sound and reasoned evidence - none was forthcoming. Do I need to show up with body bags when the preponderance of evidence clearly demonstrates what Legionella need in order to amplify and that an open system offers up a banquet of those needs to the bugs and that the elderly, very young and immune-system compromised people are more susceptible than others?

You'd think, that if nothing else, history would have taught us that contaminated water must be avoided at all costs. Used to be the leading cause of death. Typhoid, cholera and dysentery pandemics in the late 1800's & early 1900's made the current SARS panic look like a walk in the park.

But, this IS a free country and if you want to promote cross-connected open systems, that's your right. Unfortunately, the end users are not being offered the facts so that they might be in a position to make the best choice. Why not?


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Doug_17

risky behaviour

Ok, so we know you guys don't like open systems and Radiantec in particular, but I have to ask, how many of you anti-open system types drive a automobile or truck? Smoke? Drink? Overeat? Are overweight? Drink and drive? Ride a motorcycle with or without a helmet? The list goes on and on and there are bigger risks then Legionaires disease. So have another beer, another big bite of steak while you snivel about Leionaires disease while trying to scare the DIY-er away from doing his own work. Scared of a little competition from the DIY-ers eh? That's how it appears to me.

Doug_17

risky behaviour

Ok, so we know you guys don't like open systems and Radiantec in particular, but I have to ask, how many of you anti-open system types drive a automobile or truck? Smoke? Drink? Overeat? Are overweight? Drink and drive? Ride a motorcycle with or without a helmet? Looked at the death statistics for any of these things lately? And the list goes on and on. There are bigger risks then Legionaires disease. So have another beer, another big bite of steak while you snivel about Leionaires disease while trying to scare the DIY-er away from doing his own work. Scared of a little competition from the DIY-ers eh? That's how it appears to me.

Dave Yates (PAH)

No beef with DIY here

But, yours is the same tactic seen exhibited by the proponents of open systems we've seen time & time again. Sure there's risks associated with just about everything we do in life, but most folks get to decide which of those risks they will take and they do so with a full understanding of the potential consequences. Seems odd to me to knowingly sell systems to folks without giving them the facts surrounding both Legionella, scalding and pressure drop (in some systems).

I have no particular beef with any individual company unless their sales tactics are deliberately designed to hoodwink unsuspecting consumers. They're not fooling me or most of the other Master Plumbers who understand the need to protect the health of the nation via good plumbing practices. It's precisely the DIY segment we're worried about along with those who are being sold installations of open systems without the benefit of the information known regarding these issues.

The CDC estimates (and they claim these are conservative numbers) upwards of 10,000 deaths from CAP per year. There are more than 100,000 scalding cases each year that are reported for medical care (the tip of an iceberg?) with several hundred deaths. Both are preventable to a large extent. Based on your suggestion (if I understood your message), we should ignore the possibility of improving our lot in life simply because there are risks associated with just about everything.

But, then again, I'm from a State where it's mandatory to wear a seat belt in a car ($60.00 fine if not) & motorcycle drivers (and passengers) can ride without helmets! How many of those motorcycle riders go helmetless with no understanding of what the potential consequences might be? Give the consumers a similar degree of awareness where open systems are concerned and let them make an educated decision about the potential consequences & I've got no beef.

Smoke em if ya got em!

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Christian Egli

Break things into small manageable chunks

Building one system that does everything all together is an seemingly attractive idea because it allows for lower initial cost, but you are trading that cost for long term operation cost. Think about how much money you'll spend on fuel costs, in no time, you'll see that the installation cost is dwarfed. And you are only planning to save some cost on the installation, think about how insignificant that amount will be.

Hot water and radiant heat are two totally different things based on different calculations and operating under different conditions. Getting each to work at peak efficiency is difficult enough, trying to do that for both at the same time is near hopeless.

In the summer, you'll draw some hot water from your pipes, which are connected to your radiant system. What is the risk you'll be heating your house a little bit?

I like totally separate systems that can break down, be repaired or replaced independently. That choice is always easy with gas, a little less with oil.

It's up to you. Not having to be worried about Legionnella is a bonus certainly worth something.

S Davis

Competition?

How about looking out for the welfare of people in our communities by educating them on the risks involved with this type of installation.
And then letting them make their own educated decision.
I have not heard anybody bashing this type of heating system just trying to educate people about possible problems associated with this type of system.
Most of the jurisdictions that are allowing these installation are requiring a timer to cycle the water to keep it from going stagnant, so you are betting that this timer is not going to fail wich it will eventually will, now that might not be a big deal if the system in question gets a yearly service, and the service person tests the timer. but how many people are actually doing that.
So a heating professional that actually cares if people are harmed is not going to want to see systems like this installed.
Now if you figure the availibility and the escalating cost of liability Insurance, it is not worth the risk for a heating professional to even consider installing a system like this.
As far as trying to scare DIY-ers away from doing their own work, if they are here asking questions they probably have their minds made up to do it anyway, and need the information from all the people here at the wall that have worked hard to gain the expierience and wisdom over the years, and are willing to share it for free!!!!!!


Just my two cents.


Stacey Davis

Apex Radiant Heating

Weezbo

This is America Home of the Individual.

My name is william and i have to say Will I AM is a great name to have.I see a diference between willfulness and excercising my will. i belive the do it yourselfers understand the difference also. many a person i help gain clear and accurate information to better make an informed opinion prior to embarking on a course of action and wondering if there is anything that CAN be done to fix it. I suffer from the delusion that there are others like me on Terra Firma who do the same. I also have things that i feel are part of what i might call standards...when ever the codes catch up great fine wonderful till then ...wether its code or not will not change how i think things ought to be.if it is allowed in a code some where wonderful if there has yet to be a code fine personnaly i dont much care. If someone comes into my home and plunks there oversized derriere on my kitchen counter Bye Bye! Theres the door.Later.
........... maybe they didnt have legionaires disease pouring out their ventalation port ,i could care less. it just flat dont cut it with me. to me the lashing up of the heating pipe with the domestic water is in the same bag. Thanks buh no thanks. Joe homeowner is an individual in America he can do and often does...having more than one opinion whether backed with a "scientific Study"or not is a great thing in America.Sometimes people think hey that makes sence to me...maybe it sorta catches on and people think this would be a good thing to incorperate in our sanitation code. Hurray! line two paragraph 4 chapter 6 section 5 Dont plunk your arse on the kitchen counter ! HUREKA ! hurray! some day the code will reflect what may seem as common scence...until then you wont find many around here who are into trashing thier standards.

Kevin_in_Denver

PM Magazine article

I can't seem to find the original article about Aztec Radiant Systems. Does anyone have a copy of it?

Jack_23

Seems to me...

That while there are plenty of these open loop/combi type systems out there, they haven't been out there all that long. Why take a chance? It's your health or your customers, potentially, at least. It's cheaper! It's cheapest! Seems to be a poor design goal. How about, it's better, it's best, it's safest. Peace of mind is worth a lot. IMHO!

hr

Sewage and DHW in the same pipe

isn't that what we are really talking about here!? I feel all necessary steps should be taken to separate the two fluids.

If you think about it a check valve prevents backflow, yet dual check and RPZ backflow devices are required by codes. You wouldn't connect a hydronic boiler to a public water system without backflow protection. Would you?

If you agree it is prudent to apply this type of backflow protection, why not take the same steps to assure your radiant floor system and DHW are protected the same way.

Adding a HX seperation or a second water heating device for the radiant isn't that expensive, considering the risks.

Private and public water system owners and operators are always struggling to maintain drinkable water quality.

Keeping the two fluids seperate allows the proper treatment to be used in both systems.

Hydronic system fluids are not intended for drinking waters. And chlorine, flouride, and other chemicals added to public potable water systems, are really not needed, or intended, for hydronic heating pipes and systems

What's a reasonable cost for separation piece of mind? A few hundred, in the case of a second dedicated water heater, or maybe $500 for a HX separation. Hard for me to believe that many folks are that tight on their radiant budget, especially when the facts are provided to them regarding bacteria issues.

hot rod

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ed wallace

open systems

im a firm believer in taking personal responsability if you do something stupid you should not have the right to sue a manufacturer. with that said think about the possibility of poisining someone else thru tying your radiant to your potable water i am not a plumber just a lowly oil burner tech but i understand some things are very stupid

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Robert O'Connor_7

Kevin..

In checking the archives on the wall no one from Aztec ever posted. Am I missing something? FIRE! -- AIM! -- READY! Enlighten me, please. You say they don't bother defending themselves HERE anymore... Nothings fool proof...Show me the defenses...Robert O'Connor/NJ

Kevin_in_Denver

Open Direct Systems

I'll reiterate that I'm personally in favor of keeping things separate. Why take the risk for even a 5% higher cost?

However, I think that maybe the state of the art can be advanced by learning from what some folks are doing. Don't forget that you can learn a lot from doing things wrong.

A quote from Dan Holohan:

"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." "

Aztec defended themselves only at PM Mag. Radiantec is the outfit that was essentially flamed right off the Wall. Rinnai has open direct piping schematics right in their design manual. (see page 47)

Here's more food for thought... We all know that truly disgusting water comes out of a fully closed system after a while. Well, the reason that old closed system was closed in the first place was to protect the cast iron and black iron used.

The yucky stuff is the products of the corrosion that occurred before all the oxygen was used up.

If there is such a thing as a properly designed open direct system, 95% is approved plastic, a couple of brass components, and a stainless burner. No potential for products of corrosion there.

Bacteria? Maybe there are enough unavoidable things going on to prevent a toxic build up.

Like maybe small convection currents that reach to every stagnant part of the system all year long. Thermally induced micro currents are possible even inside a 3/8" pipe with a closed zone valve on that loop. Even without a timed pump to mix things up, small pressure differentials can exist all throughout any system.

Diffusion is another unavoidable driving force. Even with absolute zero flowrates, the bad chemistry of the water at the stagnant end of a pipe of any length constantly travels to the other end of the pipe. In an open system, one end of that pipe always has fresh water introduced as long as there are inhabitants in the house. By the same token, the clean chemistry at the open end, is driving itself toward the stagnant end. Diffusion is governed by Fick's Law.

There are thousands of vacation homes that are totally vacant for six month stretches. Should these folks be worried about poisoning? A typical open direct system would never be off for more than six months.

What I'm saying here is that just because we're used to seeing poisonous water in closed, stagnant systems, we shouldn't assume the same type of water gets generated in an open system. It's a different environment by definition.

Dave Yates (PAH)

learning

You're right that we constantly learn by doing things wrong. That's why we changed plumbing methods to stop drinking contaminated water that was killing tens of thousands of people each year in the late 1800's & 1900's.

As I stated before, if the folks you've mentioned are installing open systems, that's their perogative. Local codes and water co regs must be followed & a water co reg can supercede plumbing codes. Generally speaking, the stricter of the two rules rules. I do, however, think it's wrong to do so without giving the consumer/end user all of the pertinent information and options from which to choose. Bending the rules by installing cheap systems, which have a definate potential to harbor and breed a known killer is outside the boundaries in my opinion.

As for Radiantec, Robert deliberately initiated the debate both here and on another site. He made some out-of-this-world claims about his systems and then refused to support any of them with facts. I'm more than willing to consider his, or any other claims, providing the facts to support the claims are brought up for discourse and examination. If not, then they have the appearance of being a sham. Robert was given ample opportunities over several years time to produce facts - none have been forthcoming.

Actually, it was to protect the potability of the drinking water & had nothing to do with protecting the iron components. That isolation was already in place via the PRV or, in some cases, a shut off valve.

All components must be rated for potable use in an open system. There are some iron bodied pumps that carry a potable rating (typically have an epoxy coating).

Bacteria? Amplifier? Check out the CDC web site (and many others) and you'll find that bacteria, specifically Legionella bacteria, are already a problem in our potable water systems. They list a group of amplifiers and what the bugs need to thrive. Open systems provide 100% of what it is the bugs need for a perfect breeding environment. And Frick's law has no bearing on this bacterial growth issue. It has been demonstrated that highly concentrated pockets can exist within a potable system where these bacteria can colonize and thrive.

The vacation home is an example of a system that also offers a suitable environment, although its piping system doesn't offer the same ideal temperature ranges for extended periods as are found in open radiant systems. The CDC estimates there are 10,000 deaths from CAP each year and that this may be a low number. The cite the reason for the low reporting as the deaths being simply passed off as pneumonia.

The consumer should be educated and allowed to chose between open or closed. I'm all for thinking outside the box and experimenting with hydronics. But my background as a Master Plumber and licensed backflow inspector dictates caution where maintaing potability is concerned.

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