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Problems with Open radiant floor system

MTC Member Posts: 182
I'm having problems with a spring check valve in an open radiant floor system (potable, combined DHW). The original swing valve failed a few years ago, so it was replaced with a spring check. That valve has now failed as well.

The cause of the failure on this recent one is excessive build-up in the spring check (doesn't seem to be substantial build-up anywhere else that I've seen, the check valve is in about the hottest part of the system, so this seems to make sense), so thinking that the city water is in need of some filtration and/or softening?

So a couple questions. It is my understanding that bronze/SS circulators are recommended for open systems for corrosion resistance. Would bronze be preferred for this check valve over brass? The current failed one is brass. I was thinking of using a Nibco 1" lead free bronze spring check. Def higher quality than the current cheapo one as well.

Is there anything else you can do to resist corrosion on a part like this? Some sort of treatment or anything?

I know next to nothing about filtration/softening systems. Any advice/recommendations? I was thinking at least a simple charcoal filter or something to catch any sediment etc (Pittsburgh has a very old infrastructure, so might be some nasty stuff coming in from the street), then a simple softening system (don't think the city water is particularly hard, but the deposits in my check valve seem to indicate that there's enough to need some remediation).

Any other suggestions for how to best deal with this problem? When that valve fails, cold water can go straight to the hot fixtures, which is obviously a big problem.

This is the basic schematic of the system: <a href="http://radiantec.com/systems-sources/open-system.php">http://radiantec.com/systems-sources/open-system.php</a>

Thanks guys, this site rocks!



  • MTC
    MTC Member Posts: 182
    One more question...

    While I have your expert attention...

    I've been contemplating something like this in theory for quite some time, but always been nervous to just try it out on a hunch. In looking up that schematic from the last post (from the company that supplied the design/equip for this system), I came across my idea.

    Basically its to use the flooring for minimal free cooling in summertime. Check it out here: http://radiantec.com/systems-sources/open-summer-cooling-mode.php

    Any thoughts/concerns?

    Thanks again,

  • MTC
    MTC Member Posts: 182
    One last thing

    I know most of you guys probably hate open systems. I've heard all of that and understand that this isn't super popular with the pros. I'm not interested in advice to "rip it out and do it right." The system works fantastically, no complaints, other than this build-up.

    So please, only advice on how to fix the existing open system. Thanks :)
  • Zman
    Zman Member Posts: 7,372

    This is not about personal preference. It is about your health.Don't take my word for it. Take a sample of the water in your system and have it checked for legionella.

    A heat exchanger set up is just not that expensive.


    The system works fantastically , aside from poisoning the occupants.

    "Aside from that Mrs. Lincoln, how was the play?"
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • MTC
    MTC Member Posts: 182
    If we're going to take this rabbit trail,

    I'll give just a couple comments out of the myriad of things I could say.

    There's 2 things needed to essentially completely prevent growth of legionella in a water system. Temperature outside the optimal bacteria growth range, and movement of water.

    Temp: all strands have been found to die instantly at 70C, and have very low chance of growth over 50C. So recirc hot water systems in a hotel, for example, ideal is 60C out, 50C return to prevent any problems.

    My system runs between 125 and 150 degrees F. 70C is 158 degrees, 50C is 122 degrees. My return water is within these standards, and when it gets heated by the tank, brings it back up to right about at instantaneous death temp levels. This is the same for all water, both going out to heating system as well as out to potable outlets. Right before any water goes to a fixture, it gets heated enough to kill the bacteria, if any had a chance to exist in the first place.

    Stagnation. Stagnant water is the other concern. All heating season, the pumps kick on and off fairly frequently to maintain heat in the home, so circulation is consistent. No stagnation. In fact, far higher levels of circulation exist in this system than in most potable hot water runs, such as laundry rooms, guest bathrooms, etc. Come summer, every time any hot water tap is run, the floor system is flushed out with cold water, cold enough to kill the bacteria. Every shower, every dishwasher or laundry load, every handwashing... A DHW system doesn't get this treatment, many/most parts of it sit for prolonged periods at temperatures conducive to growth.

    The summer cooling add on mentioned above would be one more step to actually reduce risks even further, by keeping floors even more circulating, as well as keeping water temps below bacterial growth range.

    So, should we be concerned about potential for legionella growth in any hot water system? Absolutely. But a properly designed and maintained open system is less likely to be the culprit than a standard separate DHW system is. The real way to work towards prevention would be to require higher water temps in standard DHW, and possibly recirculation as well. Also, the majority of known cases were not related to home systems like this at all, mostly from giant water storage tanks, hot tubs, etc.

    So, any input on my actual questions?
  • Zman
    Zman Member Posts: 7,372
    Rabbits trail...

    Alright, it looks like you have your mind made up on the "open" thing.

    For me, I only had to see the stinky green slime in the tubes once and I am convinced it is a bad plan.

    As for the check valve. What type do you have that is failing?

    I wonder if a "dual check" like you would have on the service to a building would work better. Some can be disassembled and cleaned. Either way it sounds like it is a part that will continue to have issues, good isolation valves and unions will make the job easier.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • MTC
    MTC Member Posts: 182
    Thanks Carl,

    I hope I don't sound unappreciative or anything. Its just that I'm a bit tired of the standard "do it the right way" response, when there are different forms of "right," and closed systems and DHW are so often done and maintained "wrong."

    But I do appreciate people being concerned with safety. I am too, just see the merits in a simpler, more efficient open system and am willing to take on a bit more responsibility to ensure the system runs safely.

    Anyway, the current valve is a cheaper looking (unmarked as far as brand) 1 1/4" spring check. It has a plastic pin and disc that the spring pushes towards the seat, with a giant rubber disc on the end of it. This disc was worn down on the edges, presumably by scraping up against build-up on the side walls of the chamber it rides in. This made it just not quite seal fully to the seat. The design seems prone to failure, compared to the better made ones that tend to have a solid plunger with a little rubber gasket to meet the seat.

    I asked the tech at the company about a dual check, or 2 single checks... he said that it would be un-advisable due to added restriction on the operation of the circulators. There is already the main check valve in question, as well as each circulator has its own smaller check valve to prevent a circulator from pushing/pulling water through other zones. So to add another one would be 3 check valves, a decent amount of resistance for the circs.

    I did add a union right by the check valve, and use threaded valve instead of sweat, and added more isolation valves. I also plumbed in a bypass line to allow me to jump from the end of the supply to the end of the return header, so that I can shut off the floors, work on system, bleed it all out of air again, and open it back up, without having to bleed air out of the zones.

    So I think I'm pretty well set up there. Just trying to figure out how to reduce the build-up in the first place. Tech suggested water softener. Any thoughts about that? I know nothing about them, but had been thinking about doing whole house filtration of some sort anyway, so I guess the time has come.
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,221

    The check valve is indicative of what will happen to the rest of the components in the system. Water softener is not going to be the cure-all.

    I would not work on a system like this unless I was changing it to a closed loop. Therefore it would be hypocritical of me to give any advice on how to repair and maintain it.

    You came to the right place for good advice but, pretty much all you're going to get here is good advice.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,839

    You and millions of others have been misled. I know YOU don't want to hear it, and you obviously consider yourself an expert in all things legionella. So, you can take from this what you want, but it is my intention to keep other less qualified people from making a deadly mistake. As a matter of fact, besides myself, I know of two other people who had your exact system installed in their home, who were reasonably healthy, who got infected with Legionaires disease. Both of them were running higher storage tank temperatures, both had the "cold water" flush, and both had circulators with timers on their systems.

    First off, having high temperatures is one thing, but in order to completely kill ALL bacteria, there is a time/temperature exposure thing in order for scald sanitization to take place. You would have to have the WHOLE system maintained at temperatures above 130 degrees in order to completely kill all water born bacteria, of which Legionella is only one. Look up the term Legionellosis for more information. Also, it is physically impossible to get extremely hot water throughout every part of the system.

    The bacteria is in the water to begin with. Actually, it is omnipresent in the dirt, therefore it is in the water. "cold water flushing" only insures that there is a constant supply of fresh oxygenated water, carrying additional fresh bacteria and food to your legionella amplifier. In addition, during certain parts of the year, your cold water flush, and their alleged "FREE" cooling system is causing the tubing to condense, which can create unsafe conditions associated with the production of black mold and a whole other bunch of nasty diseases that your insurance company will not cover your home, or your loss of health for. Radiant cooling, done right, requires constant monitoring of the dew point (a moving target in and of itself) and adjustment in order to avoid the production of condensation.

    The use of pump timers is really not a legitimate means of avoiding any issues, and in fact, it is an extremely wasteful means of trying to appease the code authorities. How much sense does it make to pump hot enough water through the floors during the cooling season,in order to provide a feeling of false security, and allegedly eradicate any water born bacteria? Really? Based on the potential waste of energy, this deadly practice could be outlawed on this flaw alone.

    The simple single zone, single pump designs that the internet pedalers push are woefully short of a reasonably designed installation, and if a person decides they want to put in zone valves to provide one of the many reasons why a properly installed hydronc system is considered so efficient, unless the zone valves are open, and trust me on this, there are NO controllers on the market that will open the zone valves during a pump exercising period, there is virtually NO fluid being moved through the system. Even if there were, it would only serve to flush large quantities of bacteria back into the storage tank, thereby exposing an end user in the shower to a lung full of deadly bacteria.

    As for normal chemical methods of sanitization (chlorine) it would require constant exposure to concentrations of chlorine around 10 times stronger than the normal required minimums. When that quantity is exceeded, bad things happen to plastic pipes (embrittlement and failure), metal pipes (chemical erosion in copper) and human pipes. They are working on some other methods of chemical sanitization (silver and copper based products) but it is going to be a LONG time before they get their approvals.

    Over in Europe, where hydronics was invented, it is ILLEGAL to have an open system of this design in place. In fact, they require a scald sanitization of the potable hot water tank, and the distribution systems in order to reduce the potential exposure to the deadly bacteria.

    If you want some "official" information, I'd suggest that you go to the CDC web site and enter the term Legionelosis into their web search engine and see what comes back. Legionairres disease, according to the CDC is one of THE MOST misdiagnosed diseases in the WORLD. Commonly misdiagnosed as bacterial pneumonia.

    As it pertains to the codes allowing this, there are numerous movements under way to make this practice against the code without having a plate or other type of heat exchanger to isolate the space heating water from the potable water. In fact, depending upon WHO is interpreting the codes, it is already a violation of the code, because the water becomes water of "questionable character" as it sits in the heating system during non space heating periods.

    Most of the people (I am a a licensed Master plumber) who contribute to this forum are licensed plumbers, and as such are charged with the protection of potable water supplies and the health of the people who use them, and we would be in violation of some strict ethical requirement provisions for keeping and maintaining our licenses. With that said, don't expect a lot of advice condoning what it is that you have installed in your home.

    As a survivor of Legionairres disease, I can tell you that this is something that I would not wish upon my worst enemy.

    You can do what you want to do with this information and advice, but thanks for bringing the subject up, which allows us to educate other consumers who may have also been misled into thinking that the practice is safe, when in fact, it is not.

    By the way, I use to have this very same system in my own home, and when I took it apart, I saw some things (bio slime) in the tubing that I realized that I would NEVER intentionally expose my family or my customers to. This is where the bacteria hangs out and amplifies.

    By the way, it is illegal to use bronze or brass components in a potable water distribution system effective 1/1/14. so your only potential fix is to use a stainle$$ $teel check valve, and regardless of wether you go swing or spring, this problem (fouling) will raise its ugly head again, so best provide an easy means of isolation (ball valves) and removal (unions).

    Good luck in your adventures.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Snowmelt
    Snowmelt Member Posts: 1,335

    Can you get a picture of your unit and check valve?
  • MTC
    MTC Member Posts: 182
    Thanks Mark,

    For what its worth, I've always respected your input, care, and concern in your responses. You really take the time to thoughtfully answer people's posts, more so than most others on here. Thank you for that.

    I don't consider myself an expert in all things legionella, just relatively well informed. And btw, almost all of what I have learned about it came from the CDC, all those numbers and things I listed off are directly from their website.

    My whole system runs at over 120 degrees at just about all points all winter. On a particularly mild day, the loops might not circulate for a little while, and it would drop a bit, but then be heated back up to what the CDC deems lethal levels upon returning to the tank. But most of the time, return water is over 120 degrees, which should be the lowest point in the system. The dips you see between ciculation cycles are akin to what happens in a DHW system's supply pipes as they sit between uses. But this water goes directly to the consumer after this, rather than being heated back up to lethal temperatures first as in an open system.

    I've checked my pex tubing many many times for condensation. I've never seen any on it. Copper, yes sometimes you might get a little sweating, but I've never had any signs of it on a cold pex supply line (one of the many reasons I'm a Pex fan over copper these days). Now granted, if you were using a chiller and constantly running cold water through your floors to function as "real" cooling, you'd likely find that condensation point pretty quickly for pex, but for standard water usage, which is the only time this limited cooling will occur, I've yet to see any evidence of sweating. If I do install the cooling loop, I will be sure to monitor the exposed pipes, valves, etc closely for a while to ensure this lack of condensation continues - thanks for the reminder on that front.

    Again according to the CDC, cold water is non-conducive to legionella growth. Anything below 25C is considered non-conducive to growth, and 20C to be extra safe. 20C is 68F, 25C is 77F. With cold water coming into the house at 40F or so every time any potable water, hot or cold, is used, the floors will stay well under this range and be nearly constantly circulating.

    While I'm sure there are many companies out there pedaling single zone systems, this is not one of them. I have 3 zones, with separate circulators for each. All parts of the system are open to flushing at all times. No zone valves.

    I'm sorry to hear that you had to deal with Legionaires... was it able to be definitively linked to your heating system? I know the CDC claims that there have been very few cases positively linked to water distribution systems in residences, but they leave open the possibility that many are undiagnosed, particularly among the elderly. Most confirmed cases have been linked to water storage towers, hot tubs, and similar types of stagnant warm water.

    I don't mean to minimize your terrible experience, just searching for truth. I stand behind my thought that a well designed combined system actually adds some preventative measures compared to a separate DHW system, which often has long periods of warm stagnant, lower temperature (in bacterial growth range) water. And this thought is from looking up data from the CDC, from analyzing the water movement and temperature from these systems, etc, not from manufacturers claims. I've thought through it myself extensively, and I see what I perceive to be about the same level of concern with a standard DHW system and my particular open system (can't speak to a zone valve system, that actually sounds like a bad plan to me w/o looking into it too much). However, I'm open to hearing explanations of what really makes my system much different. I just haven't heard it yet.

    The bio-slime. Can I ask where you found this? I've had my system opened at several different points several different occasions (repairs as well as remodeling that required moving floor tubing, etc), and I've never seen anything but completely clean pipes. The only exceptions have been mineral buildup on the check valve, and a tiny bit of mineral buildup on the bottom of the system's main copper supply header (that feeds the circs). Everywhere I've looked into the pex has been totally clean.

    Also, I should note, that due to the controversy surrounding this type of system, I DO NOT advocate others to install them. I feel pretty confident in my assessment of my system so far, and confident that I have taken measures to ensure its safety that the average consumer might not do. But I don't advise it to others, for whatever that is worth. I wouldn't advise anyone install this setup w/o a really good understanding of how the whole system works, as well as the risks associated with bacterial growth, and preventative measures available (all available to research on CDC site). The more I research it though, the more I think that I feel about the same about the risks associated with standard DHW systems, which every home has already.

    Can you clarify this 2014 law for me? I was aware that the law had changed, but I thought it was just that fittings are required to carry the double oval lead free marking? Am I mistaken about that? What are you supposed to do for shut off valves then? The check valve I'm considering is certified lead free bronze, labeled from Nibco as potable water rated. I have already got a union right next to the valve, and isolation valves all over the system, and even a bleeder bypass to allow me to bleed out the headers separate from the floor zones after working on the system.
  • MTC
    MTC Member Posts: 182
    edited April 2014

    Here's the only one I have on hand. I drew a few lines on it illustrating how the summer cooling diverter could be installed, with no long runs of pipe that would go stagnant in off-season (only a few inches on one side of the diverter or the other would not be directly flowing at any given season).

    Right above the drawn in diverter is the check valve. Its a cheapo brass spring check. I'd like to put a better quality bronze Nibco check valve just a bit further to the left on the supply header, where it has a bit more room for access if necessary. Its really tight where it is now. There is already a union there right between the current and proposed new locations. I might put a second one in while installing new check, but the one does make it easy enough to get at it.

    DHW comes off the hot supply outside the pic just above the tank. It used to be the red pex line you can just barely see behind the return going vertically back to tank. This is now just another bleeding port. Think you can see just about everything else in the pic, but the words are hard to read. Bottom right red pex is an air bleeding bypass to bleed out manifolds w/o having to run through floors and rebleed them. Blue pex is water from street. Currently cold fixtures come off this upstream, if summer option is added, the cold fixtures will come off the top of diverter tee, the new blue drawn line there.

    Let me know if there's any questions.
  • Gordy
    Gordy Member Posts: 9,514
    Dont mean to cut in

    And I'm sure you are tired of hearing about open systems.

    You seem to have educated yourself some what on this topic. Some points you are missing.

    Legionella just loves the temperature you run your system at in the winter time. 130 plus degrees is what you need to eradicate legionella this takes a period of time the higher the temperature the less time needed. This lowers the bacteria population, and does not 100% eliminate it. Just brings it down to acceptable limits. Also while legionella does not bloom in 40-70 degree water it is ever present, waiting for the right conditions to propagate in your system.

    While most healthy people may never contract it. The point is why take an unneeded risk to the added exposure. Much easier to contain a sole purpose domestic water system with considerably shorter runs of pipe than a combined system with much longer piping for bacteria to hang out.

    Also how old is your system while it may be bio free now, think about decades from now. My radiant system is over 60 years old with 5000 feet of pipe it makes me want to yak at the thought of my fresh water being handed to me through all that pipe if it were an open system.

    another thought is future owners, or visitors that may be handed your system with little knowledge of its possible health hazards. They may be the ones that are elderly, or have deficient immune systems.
  • MTC
    MTC Member Posts: 182
    No problem,

    I welcome "cut-ins." We're here to learn and educate.

    Legionella does not love the temp I run my system at. I'm between the ratings where it is very difficult for them to proliferate at the low end, and at the point where they're at nearly instantaneous death at the high end. This is according to the CDC. Many people run these systems at like 90-120 range, which would be exactly as you say, but my system runs at 125-150. Granted, between cycles, the temp will dip down into that range for a short period of time, but not very long, and then it is pushed back into a lethal level water tank before it can go out to fixtures.

    As I've been saying, I don't see it as an unneccessary extra risk, i see the operational method as additional protection against the risk of legionella that exists in the separate DHW systems everyone is advocating. Talk about long lasting stagnant, perfect temperatures for legionella, that's where that condition exists. Far more than in my particular open system.

    You know what really makes me want to yak? Drinking from the 100 year old city distribution system. The system that likely has lead lines here and there, that has whole colonies of god knows what living in it. Its the trip to my house that worries me more than anything. Which is yet another reason why I like my system frying the crap out of the water before it goes out to my fixtures. This is not done, not practical, and sometimes not even possible, with a DHW system, depending on your equipment. It certainly isn't done much.

    The length of the pipes is definitely one key difference between the systems. Its honestly the only thing brought up so far that I think has some merit to the opposition to this system. Given bad operational conditions, the length of piping could present some concerns over and above what you find in DHW. This is certainly valid. I think a properly designed open system addresses these concerns though. No standalone DHW residential system I know of being used in normal houses uses high enough heat to kill off the bacteria that come in all day long. That's a bigger concern to me than an open system. DHW loops off of boilers and the like do address this, but that's moot for the millions of people out there with Burnt Air systems.

    My system isn't that old yet, about 8 years. If your system is 60 years old, I assume its soft copper zones? That honestly bothers me a bit more than Pex, both in trusting the piping for radiant heating, as well as if it were an open system. While I'll grant that we may or may not someday learn that there's some currently unknown leeching from Pex systems, based on what we do know about both systems so far, I'm more comfortable drinking out of Pex. Particularly when water spends a decent amount of time in there. Just seen too much crap grow in, come out of, etc copper piping.

    If I were to sell my house, I would advise future owner of proper maintenance of the system, and the controversy surrounding it. They can then choose to convert it to an HX system if they choose. But I'm not leaving my house anytime soon. By that time, I think this whole debate will be solved one way or the other.

    So why take the risk? I don't see it as additional risk. What I see as primary risk is normal standalone DHW systems. A good HX system based around high heat would be sort of a balance between the two, but if I had a separated system, I'd be operating at lower temperatures, and it would basically be back to the same concerns I had before about low temps in a DHW system.

    FWIW, I think that the next best improvement to this open system would be using smart circulators. This would allow for even more consistent temperature control and virtually zero chance for any type of stagnation, as you could set the floors to run much more constantly than a set speed circulator. But that's a different rabbit trail...
  • MTC
    MTC Member Posts: 182
    Filtration systems, etc

    Anyone have any good advice about filtration systems? I have city water, which is okish from the city, but has to go through an aging distro system. There's a moderate level of hardness, but nothing too over the top.

    I'd like a whole house filter system anyway, just to clean things up for my drinking water, showers, etc. Now with this bit of buildup in my check valve, i'm thinking about reducing sediment, as well as calcuim etc, if possible. I'd rather do this without going to a full salt system, I don't like some of the tradeoffs.

    I understand that carbon filters are effective at removing a lot of contaminates, but that they also remove any levels of chlorine, which can be beneficial to retard bacterial growth. Any thoughts about this, given that unless someone comes up with a really great argument, I'm going to keep my open system? Would carbon be beneficial/harmful/balance itself out regarding concerns with the open system?

    I def want at least a like 5 micron filter, just to get rid of any random junk from the city piping. Maybe a UV treatment? Any thoughts about those?

    There are also those electro-magnetic things that claim to chemically alter the hardness in water, so that it won't attach itself to the inside of pipes. Things like the Eddy system. They sound so much like marketing BS that I have a hard time believing there's any merit to them, but anyone have any real experience with them, or expertise in the electromagnetic/chemical process that they claim are being used here? Reviews online seem to be fairly positive, and Eddy stands behind their product for a full year with full refund if you're not happy, which is a bit more confidence inspiring than most of these kind of gizmos.

    I know most of you (maybe all of you) don't like my system. I've started discussing why I support it, and since we'e started the debate, I'm willing to continue talking it out. But, barring someone giving me a really good reason to agree with you, I'm not likely to change it over. Given that, even if you wouldn't go into a client home and do these things, can you give advice for how to make an open system as safe as possible, and fix some of the nuisance issues like mineral buildup on a valve? Your position has been heard and noted, and anyone who hasn't made up their mind about open vs closed has seen your reasons. I'm operating with a system fully legal by today's codes, so there's no ethical reason you can't advise how to make it work the best it can, even if you reserve the opinion that the best course of action is to change it over.

  • MikeL_2
    MikeL_2 Member Posts: 382
    edited April 2014
    I agree with M E

    You are not going to convince any of us, who take our job of providing & maintaining sanitation very seriously, to condone, or agree with your methods.

    Plumbing Code was developed, and written after identification of an event, or series of events, that led to some type of water born contamination, which resulted in illness, or death. Plumbing Code is also based on potential, and if you continue to challenge nature, and provide an environment that can foster the growth of Legionella if one or more of your checks & balances fails, potential will be realized, with devastating results.

    There are alternatives to your design and strategy, that would eliminate the potential for Legionella, why would you choose to ignore them?
  • RobG
    RobG Member Posts: 1,850
    The Problem

    This is the problem with the Internet peddlers / designers. For the cost difference of the two additional stainless pumps, you could have installed three cast iron pumps, a flat plate heat exchanger and actually saved money and had a safe and functional system. Do you have o2 barrier tubing installed?

    Do you warn family and guests about the questionable water at your home?

    Step over a dollar to pick up a penny.

  • MTC
    MTC Member Posts: 182
    Plumbing code...

    does not have a problem with my system. And its been updated 3 times since my particular system was installed, and probably many times more than that since these open systems have been in use. So apparently the arguments aren't flying with the code officials yet either.

    Even my county, which is known as being one of the strictest plumbing codes in the nation, does not prohibit it.

    Sorry, your argument has no basis. If you want to actually try to explain WHY there's a problem with my system, then we can have a discussion. But apparently nobody has been able to do that well enough yet to convince even the strictest of code authorities.

    The alternatives do absolutely nothing like eliminating the potential for Legionella. Its there before any of the heating systems come into the picture. And a standard DHW system cannot kill it off, so no, this is false. Its just a different type of controlling the bacteria that is there no matter what.
  • MTC
    MTC Member Posts: 182
    No arguments here

    I don't disagree with your assessment that the cost difference is negligible in many cases, if existent at all. But that's not relevant. I looked into both open and closed systems, chose the system I wanted, and then bought it. Price had very little to do with it. In fact, I never even priced out a closed system, I had already decided it was not what I wanted.

    So please - while many people may be suckered into cheaply made, poorly designed systems based on cost alone, it is not the only reason people go the open route. Don't assume that, and certainly don't accuse me of it. I chose my system b/c it is legitimately what I wanted, and I still stand behind that decision.

    O2 pex? No. Its an open system. Fresh oxygen rich water flows through it constantly, so preventing small amounts of oxygen diffusion through the tubing is like putting silicone around the perimeter of a screen to keep out the draft. Absolutely necessary in a closed system, not in an open one.

    Let me ask you a question. Do you have arc fault breakers on every circuit in your house? If not, do you warn your guests before they come in of the imminent risk of the house catching fire?

    Seem like a bit of a stretch of a comparison? Actually, it's not that great of a comparison - arc faults are code mandated, open systems are not prohibited by code. Also, the cases of fires as a result of arcing probably outnumber the cases of legionella by 10,000 to 1. And, we actually know where the fires came from, most of this idea of legionella coming from open heating systems is pure guesswork. We simply don't know exactly where a lot of the cases originated. All we know is things like mass water storage tanks and hot tubs are the largest known contributors.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,839
    Response to MTC.

    Sorry, life got in my way… Thanks for the kudos. I try and be as reasonable as I can, regardless of who or what is being tossed out. This forum is about people learning. I am here to share my knowledge and experience.

    Information from CDC is somewhat misleading in that ti doesn't give you the required time of exposure to completely eradicate the dangerous pathogens in the water, Also, the bacteria have the ability to shield themselves with numerous defense mechanisms. Hospitals have proven over time that the acceptable scald sanitization temperatures are inadequate, requiring them to do a long term and regular flushing with outlet temperatures at the spigots at 180 degrees for at least an hour. Yes, your temperatures are supressing the bacteria count, but complete eradication requires a lot higher temperatures for a lot longer periods, and flat plainly and simply stated, there are no guarantees that it will be completely effective in corralling the bacteria and killing them completely off. Isolation with a heat exchanger is the only guaranteed way of limiting a known exposure to a know hazard/source.

    As it pertains to biofilm/bio slime, unless you physically cut the tubing, you will not realize it is there. It is in ALL of the plumbing water lines. Its presence in copper is less noticeable than in plastic. Plastic represents a perfect growing medium. Copper is a natural suppressant to the growth of bacteria. Copper sulphate is commonly used to control algae growth in ponds etc. Trust me, it IS there, and it is an ideal growth medium to enhance the amplification of bacteria. As it pertains to potability, our water (North America in general) is substantially much better than most of the other water of the world. Without the methods we use for chemical sanitization, our population would be MUCH worse off than we are. If you think a well source would be better, remember that one mans leaching field is another man's surface water source. Also remember that the bacteria is in the dirt, therefore its in the water. CDC has done numerous studies, and continues to update the data. Most people who drink water are exposed to the bacteria, without harm. It is when your immune system is depressed, and you inhale the bacteria deep into your lungs that it becomes an issue. Once into your lungs phillia (small hairs) it is in an ideal growth consideration and begins amplification and infection. Unless you can guarantee that you can kill 100% of the bacteria, which you can't unless you are willing to run MUCH higher temperatures throughout your WHOLE system ALL the time, you have a potential. Studies have found bacteria still inside of tanks maintained at high temperatures due to stratification layers which occur within the tank naturally.

    Re: tube condensation, under your current method of operation, you've not run it long enough to see sweating. Hook it up the way they recommend with the bypass, and start irrigating your homes lawns, and you WILL see condensation production. It's not the first, and won't be the last time its' been seen. The only good thing about mold growth, is that if you take away just one critical required element, the bacteria ceases growing. The bad thing is, as soon as that missing element is reintroduced, it comes back. Moisture is key.

    Internet peddlars have a tendency to be material intensive designs. They are dealing with DIYers, and DIYer's rarely know how to properly solder, so they configure them with as many non soldered connections as possible. Pumps cost a LOT more than zone valves, in initial price as well as the cost of operation, hence your pumps. Mechanical items are subject to potential failure. Timers fail, pumps fail, check valves fail, and then a bacterial colony gets a foot hold. It is an acceptable method, but the use of zone valves is also done, and there is not a controller on the market that will open zone valves and purge zones. Trust me, I've already researched this item for proposed code changes.

    My exposure and contraction came from asimple 30 gallon LP self contained water heater tank in my second home. I was trying to save propane so I wouldn't have to move a full LP tank, and was turning the tank to PILOT during the week when I was not there, and when I was there, I kept it set just above vacation low, again to conserve LP. And yes, regular DHW systems DO represent a substantial point of exposure, and yes we are fighting an uphill battle to get it addressed, and it is being addressed in the codes, but due to the open consensus process, will most probably get shot down in the end by water heater manufacturers. The solution is higher hold temperatures, less dead branch lengths, and anti-scald mixing valves at the source of supply and the points of use in some cases. Research continues on an acceptable method of sterilization, but immediate relief on the horizon. The reason that the CDC can't definitively point their finger at DHW heating systems is because it is not required to report cases of bacterial pneumonia, which is the first diagnosis. In my case, I had to ASK to be tested after exposure. My MD didn't want to test, but instead wanted only to treat. Same thing with associated deaths. For example "Poor old guy passed away. What'd he die from? Pneumonia. Oh, too bad. Oh well, he had a good long life…" If additional research had been done, they would have found the infection. It is THE most common misdiagnosed disease in the WORLD, and domestic hot water heating systems, and extended systems like your own are known hangouts for the bacteria, and in certain cases are considered ideal conditions by which the bacteria can amplify.

    The scale you found in your pipes also acts as a house for the bacteria. They need this stuff to colonize. The bio-slime is universally coating the insides of the pipe. Next time you have the system open, use a Q-tip and wipe the insides of the pipe. You will see it. It exists every where in the water. Your system has a LOT of moving parts, and unless you hug your heating system every day, all it takes is one component to fail (i.e. timer of pump or check valve) and your exposure to the bacteria increases significantly.

    Quite honestly, the CDC has not specifically studied this type of system for potential issues. Their research is primarily based on the noscomial (hospital) settings, and they know if its there, where prescriptive avoidance is being done, and still isn't effective, then it is fairly safe to assume it is in your system and systems line theirs. If it were as safe as people say t is, and proven, then I'd have no issues with its use. Unfortunately, those studies do not exist.

    Lastly, your assessment is correct. The new lead free laws must be adhered to. The new lead free "copper alloy" fittings are a royal PITA to solder,so good idea to go with threads. I suspect that long term, we will probably find other "issues" related to the lead free fittings that will cause us to look back and say "What WERE we thinking with that move???" But only time will tell. Sometimes, our government does things to us in the name of protecting us, without looking at all of the side consequences, but that is a topic for another place,and another time. Thank you for acknowledging that this system should not be recommended to just anyone. Even under perfectly ideal considerations, there still exists a potential of inadvertent exposure, that can quickly accelerate into bacterial pneumonia.

    It sounds as though you have a substantial background in the trades. You are not the norm that attempts to do one of these systems. Our primary concern is peoples health, not the potential loss of business associated with the DIYers of the world. Most of the people who frequent this site are DIYers to one degree or another. I am. But I have had enough exposure (38 years in the trades) to know that I am comfortable doing the things I do. I am also the first to admit my lack of knowledge and or skill and will hire qualified person to take care of those tasks for me.

    Thanks for keeping this conversation civil.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • idahohr
    idahohr Member Posts: 13
    You are not alone

    MTC, here is a picture of the heart of my open system. It has been absolutely trouble free for about 15 years. I replaced the igniter on the Polaris water heater.. It heats 2000 sq ft on two floors. The four zones are controlled by 4 Aube TH 114 line voltage thermostats, water temp has always been set at 125. I pulled one of the pumps out a couple of weeks ago and there was no sign of any corrosion or gunk. Our water usually smells like chlorine and is soft so fortunately no problems there, Our kids are gone now but they didn't seem to get sick very often, I had the flue in 2005 so maybe some connection there.

    That being said, I am about to sell this house and will probably add a fphe, another pump, a pump controller that has a system pump option, expansion tank etc.
  • MTC
    MTC Member Posts: 182

    Once again you show why I like your posts so much :) Great, well thought out response. The best actual argument I've heard yet, by far, for the position you all hold.

    So, I went to the CDC site to look up a document, and couldn't find it. One of the best resources I've found so far is in fact not there, but on the WHO site. Sorry, I remembered the source wrong. Anyway, here it is: http://www.who.int/water_sanitation_health/emerging/legionella.pdf

    Many of the studies cited are pretty old, so maybe some newer studies have found differently, but most of what I've spoken about comes from this very comprehensive document. Such as they claim that all strains were killed nearly instantaneously at 70C, and the hottest systems they were able to isolate any legionella from was 66C (about 151F). These are, most likely, laboratory conditions, and of course real world conditions, like many things you mentioned, do alter these results somewhat. This brings us back to the core of my position - that an open system is roughly equivalent in risk to a standard DHW system. Open system has more piping, so more area for bacterial growth, but also much higher temperatures and more circulation. These things offset each other substantially.

    So the question remains, is an open system any more inherently dangerous than a DHW system? I think the answer is, it depends. If you don't maintain good circulation and high temperatures, then yes, it has more risk. How much more, its hard to quantify, but more. The zone valve system sounds to me (without spending a lot of time looking into it) like a system that would greatly reduce the circulation in the off season, which means both long stagnation periods and warm temperatures in that stagnant water during the summer. This is a recipe for problems. I don't think I'd be comfortable with that system. But a system designed to be circulating all the time, and operated at high enough temperatures to at the least retard bacterial growth, could actually be a step up from a DHW system that often runs at temps right in the bacterial growth sweet spot, and has a lot of long stagnation periods.

    As Mark's experience shows, its simple to have the "proven" system create a problem - doing something that makes perfect sense, trying to reduce waste of energy while away from home, can turn a presumed proven safe system into a big problem quickly. Also, the high level of misdiagnosed cases of legionaires in the elderly doesn't lend itself well to the conclusion that open heating systems are the culprit, but much more so to the concerns related to DHW and hospital environments. I doubt a large number of our elderly population have an open radiant floor system in their home.

    Biofilm is something we apparently can't avoid at all, in any system. So once again, the longer runs of tubing allow for more surface area for that biofilm, but again, this can be offset in many ways by higher circulation rates and temperatures. I would rather have longer runs of piping that is maintained at high temperature and consistent flow, than shorter runs of piping, also full of biofilm, that are allowed to sit for long periods of time at temperatures very conducive to bacterial growth.

    As far as municipal water, I agree. Its fairly safe - the treatment practices, required testing regimens, etc make our city water pretty safe. At least when it leaves the treatment facility. What scares me is the miles and miles of old distribution lines. But even given that, I don't think its necessarily better or worse than well water, just different reasons for concern.

    Regarding condensation, I was referring to pex supply lines in general. I've run substantial amounts of cold water through pex supply lines in my house as well as in other properties, and never found that normal house usage would produce condensation on the pex. Some would form on Copper in heavy usage, or unusal humid room conditions, etc, but I've yet to see it on pex under normal usage. I use mostly low flow fixtures, efficient appliances, etc, so that helps in my house. I also live in the city, there's no significant yard watering going on, as there's no significant yard to water. But, as I said, if I put in the cooling setup, I will monitor the piping closely for a while to make sure.

    Thank you for at least acknowledging that the concerns are similar between DHW and my system. That's the first time someone has done that in response to my arguments. It makes me take you more seriously in your other arguments, as this is just a common sense conclusion to come to based on the same reasons for having concern with an open system.

    Thanks for the confirmation about the lead free code change. I am using threaded, as I need to be able to open up the system to clean out corrosion, at least for now, until I can figure out how to reduce/eliminate it as much as possible. Also, I hate sweating brass/bronze of this size. The threaded copper adapters aren't too bad though.

    Yes, I'm in the trades - I am a residential renovation contractor, and interact daily with pretty much all trades in the residential construction world. I don't particularly like the idea of a DIYer tackling something as complex as a full heating system install of any type, so I hear/agree with the concern about systems marketed as very DIY friendly. I'm all about DIY, but some things require at least a very substantial knowledge to undertake them. Most HVAC, plumbing, and electrical work is definitely in that realm, and at the very least, a DIYer should be overseen by a competent professional in large projects of these natures.

    So, going back to the actual reasons I'm posting here... what can be done to make these systems as safe as possible? And by these systems, I mean both DHW and an open heating system, as they share similar concerns. Higher temperature and lack of stagnation having been addressed already what other options do we have?

    I'd like to reduce/eliminate scale buildup in my system in general. There are expensive parts and pieces, and I don't want scale in the pipes that my drinking water goes through regardless of what kind of system it is. Also, as you mentioned, reducing scale will reduce potential legionella growth locations. So, what are the good options?

    Does anyone here have extensive knowledge of whole house filtration? UV treatments? Things like the Eddy system? What can we do to reduce scale, as well as biofilm, legionella entering the house in the first place through the supply water, other bacteria, contaminates, etc? If we're going to discuss the health of our drinking water, this is an important topic.
  • MTC
    MTC Member Posts: 182
    Thanks for the support,

    I know there are plenty of these systems out there, and while people on here talk about them being a deathtrap, there seems to be thousands of them out there functioning just fine. Not a reason to not be mindful to use safe practices, but indicative that the problems don't seem to be so strongly linked to open systems as people might lead you to believe.

    Why are 3 of your zones shut off? I don't think I'd recommend that for anything short of quick maintenance - it is important that your water not stagnate.

    Why the big conversion? Just worried about the risks if the next owner doesn't know how to properly maintain operate it?
  • idahohr
    idahohr Member Posts: 13
    Was in the process of

    Purging the loops individually. When I start the heating season, I always force water through each zone for awhile. This winter I only ran two zones, was gone quite a bit. When I came back, I purged the zones that were not being used.

    Yes, considering the change over because I don't think the system would be allowed. When I plumbed the house, the lines coming off the Polaris were not hooked up. The plumbing inspector saw it and couldn't say a thing because it wasn't hooked up. He said it looked nice though. After he left I hooked it up.

    That being said, if I build another house, it will be a mod/con boiler and outdoor reset.
  • MTC
    MTC Member Posts: 182
    Oh, ok

    I don't know your local code, but it would not have been an illegal system when you installed it unless your local authority banned it. Its still legal here, and we have some of the strictest code in the country. That said, if you inspector don't like it, it don't fly...
  • MTC
    MTC Member Posts: 182

    Nobody has chimed in on water treatment yet, but I've been researching on my own a bit. I'm going to put in a double big blue filtration system with 5 micron sediment filter and 5 micron GAC carbon filter, followed by UV treatment. For city water, this should be over the top treatment, but clean out a lot of the stuff that might be picked up along the distribution system, etc, and remove a lot of the trace chlorine and things left over in the water so that we're not drinking that. It's also nice in that its as much as a year between maintenance (changing filters and UV bulb), possibly shorter if the city water clogs up my filters faster.

    The UV inactivates most bacteria, including Legionella, making it unable to reproduce, and therefore harmless. It should also greatly reduce the buildup of biofilm, as the bacteria will be inactivated. Having good filtration before the treatment ensures clear water to ensure good UV treatment.

    Seems most UV manufacturers recommend sterilizing your whole water system with bleach upon install, so I think I'll go ahead and do my whole system while I'm at it. Something like this procedure: http://www.watertreatmentguide.com/DetailedDisinfectionProcedure.pdf, though I imagine I'll need a a little to refill the filter housing with bleach a couple times due to a larger piping system.

    I know this probably won't make any of you like my system, but it creates a lot of layers of protection on top of each other to reduce potential problems not only in the heating system, but throughout the whole house's water supply. I wanted to do water treatment for the whole house anyway, regardless of heating system type, so this all works together pretty well.

    Any thoughts/suggestions?
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,839
    No expertise in water treatment on the potable side...

    But I am aware that if a UV light is used, that it can and will ENHANCE certain algae blooms. Make sure the one you buy has a "bulb wiper" assembly, which will allow you to physically clean the light bulb of any alga that has accumulated on the light emitting surface.

    Filters are also going to create a pressure drop you didn't have before. With a municipal water system, it shouldn't be a problem, assuming you have decent water pressure to begin with.

    I have successfully used magnetohydrodynamic water conditioners for treatment of limescale, which is sounds like you are dealing with. I have been publicly chastised for stating so, and quite honestly, I DO NOT CARE. If it didn't work, I wouldn't have suggested its use. I've used them all over this country, and with the exception of some :glass water" conditions, typically found in Texas (silica calcification versus lime calcification) they work as designed. Are there some bogus hocus pocus devices out there? You betcha, so make sure you are dealing with a reputable organization, like Chemtune.

    The only thing I use to do for water treatment was to remove sodium ion exchange softeners due to the health hazards associated with its use for people with a propensity to have high blood pressure from ingesting sodium.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • MTC
    MTC Member Posts: 182

    Good to know about the algae thing, hadn't heard that before. I know the one I'm looking at has a removable glass sleeve that goes around the bulb, i presume for cleaning purposes. You have to change the bulb every year anyway to keep up proper sterilization, so will be a good time to do some cleaning.

    Yeah, I"m aware of the pressure drop thing. Our pressure tends to be a tad on the high side, so not worried about that, it may even be a good thing for the fixtures. I'm also putting in pressure gauges on both sides of the filters, so that I can monitor the level of clogging in the filters by pressure drop. Seems the most logical/accurate way to know when you need to change them out.

    Ok, now you've lost me :) I'm assuming that GIANT **** word you just threw down is the technical term for the electromagnetic gizmo thing I was talking about earlier? :) I've never heard of Chemtune, and a quick google search of it and your super-word brought up, well, this HH post, so no particular help there, haha. Anyway, can you give me some more info about this? Is the Eddy one of the type of product you're referring to, and if so, do you know anything about it? It seems to get good reviews, people who didn't like it said the return process in the 1 year warranty was pretty easy, etc. It looks cheesy as hell though... http://www.eddy.uk.com/Electronic-Descaler/Water-Descalers.php Amazon reviews look pretty decent. http://www.amazon.com/Eddy-Electronic-Water-Descaler-Alternative/dp/B003Z96GR4?SubscriptionId=0E73DDYC8NA0NSVWPE82&tag=askville-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B003Z96GR4

    Thanks for being willing to stand up for things you believe in publicly even in the face of a lot of opposition. I respect that, as you might guess from me coming on this site talking about open systems, knowing full well how the general community here feels about them...

    Glad to hear we're on the same page about water softener systems, at least the salt based ion exchange ones. Not only are there health issues, but it causes some other problems with corrosion, etc. My water isn't THAT hard, think it came in at 5.6 grains average or something from the city, probably picks up a bit more on the way here. Puts it only in the moderate hardness level. But at high temps like I have right by a check valve seems to make it accumulate more than it otherwise would, so looking for a way to address it. Just getting a lot of the sediment and things out will probably help some too.

    Thanks again Mark, for all your time and effort here. I appreciate it.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,839
    I've used all of them...

    They all work on the principal of running water through a magnetic coil field.

    The last one I installed at my mountain home was a clear wave,


    I've spoken with people who have said they could TASTE a difference. I don't drink the water from up there, but can tell a big difference in the way water comes off of dishes etc. It sheens off whereas before it just stuck to the dishes and dried leaving a hard water mark… There are still lime marks if you don't hand dry (we do), but they;re real easy to get off.

    Thanks for contributing. And thanks for the thanks. I'm here to help.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.