bio-contamination in radiant system

jerry scharf_3 · January 2006

Brad,

As Dave has taught us all, chlorine at drinking water levels do nothing to Legionella. I get that makes it a Hulk.

Bill,

By the heating contractor a nice bottle of something. He saved you and your family from significant health risks.

The way you fix this is to put a good flat plate heat exchanger in between the domestic hot water and the heating loops. You will need another circulator and the controls chnaged as well. Probably want to get a pro to do this.

jerry

Bill L · January 2006

bio-contamination in radiant system

I have what is described by the Radiantech website as an open direct radiant system. It uses Wirsbo tubing and components and a Bock oil-fired water heater. The water source is chlorinated city water. Heat loop water is 120 degrees. The system works very well.
I had a local heating contractor come by to give it a checkup. He was horrified by what he thought was the certainty of nasty bacteria growing in the heating loops, which would cause health problems (through the use of contaminated domestic hot water). He also said this type of system is a code violation here in Alaska.
Should I be worried? If I were to test for evil bugs, what types/species should be looked for?

Brad White_9 · January 2006

Oh, Legionella.....

aspirgillus, typhoid, various anearobic bacteria (stinky).

The water temperatures in radiant systems turn the water from a heating source into a dating bar.

Generally though, chlorine kills most anything of concern, but chlorine and its derivatives are not a welcome thing in most heating systems. What survives has to be the Hulk Hogan of bacteria. If you use glyclol (a sugar essentially) in low concentrations you will get some bacteria that really smell badly. You could play "pull my finger" and everyone will understand.

Next time use a heat exchanger and separate closed circuit. Some plumbing codes require a double-vented heat exchanger as a means of backflow prevention.

Brad White_9 · January 2006

Agreed

Legionella is the Hulk. I did miss the Dave part though.
Makes sense in that my plumbing department designs their DHW for 140 degrees and does not rely on municipal chlorination.

(Wonder if fluoridation gives Legionella good teeth?

)

As an HVAC engineer, my Legionella experience is with cooling towers. As you know, cooling towers are treated at higher levels than for drinking water and I have never heard of Legionella in a properly treated cooling tower, especially with a one-two punch of different alternated biocides.

Bill de Jong · January 2006

WATER HEATER HEATING SYSTEMS

Hello from the land of Dual Purpose Water Heater Systems(Alberta). In this province, using domestic water heaters for Potable/Space heating in Combo Systems is quite common. We have provincial regulations to govern the installation and design of these systems as well. One of the most important parts of the regulations is the clause which dictates that the system have the capability to change the water in the slab at least once weekly, thereby moving the water back into the tank and on to your bath or kitchen sink before contamination can occur.During Heating Season, this is not an issue. During summer, a timing device could be used to activate the pump(s). We have been doing this for several years and have yet to hear of any contamination. Hope this helps!

Dave Yates (PAH) · January 2006

ah-hem

Where's the tests to back up your claims of zero contamination?

Once a week? Good grief man. Get thee to Google and type in "hot water + Legionella". You'll find Legionella absolutely thrive if all of the following conditions are present: pH of 5.5 to 8.0; water temps between 55 and 133 F with 98.6 F being ideal (even if you store at 140, a rad system loop temp will be falling along the course of its length - right down into ideal growth range); biofilms - present in all potable systems - especially in tanks AND horizontal runs of tubing; and stagnation. Now, they don't need all of those conditions to survive and thrive, but give em all four and they'll turn that dating bar into an orgy.

Five previous tests performed on water heaters (back when they came set for 140F by the factory) confirmed that a percentage tested positive for Legionella Sero Group #1 bacteria. One of those tests was performed in Canada.

Now, tie a dating bar onto a system (already tested and proven to be a multiplier for bacterial amplification) where it's already known a given percentage will contain a dangerous bug and let it off for a week at a time to give the bugs the luxury of stagnant water in hundreds or perhaps thousands of feet of plastic tubing (plastic supports bacterial amplification a bit better than copper). Then let-er-rip to re-colonize the domestic amplifier and its distribution system each and every week - as long as the circ is working - it's guaranteed never to fail, right?. If the circ fails, who will know and, more importantly, when???

Can't say as I'll ever understand the stubborn reluctance to do what must be done if the consumer is to be protected.

Chlorine doesn't do squat where Legionella are concerned. For starters, its concentration would have to be 10,000 times greater than the 2- to 4-PPM in municipal potable water systems. Secondly, as water is heated, chlorine dissipates - attacking metallic components. Thirdly, at 20,000- to 40,000-PPM, chlorine will combine with organics to form carcinogenic compounds.

Are the systems you've described contaminated? I don't know, but I do know enough tests on potable systems and water heaters have been done to confirm there is a bacterial issue before anyone ever decided to add on an open system. Given what's known about bacterial amplification, it's an absolute certainty that if an open system happens to be colinized by Legionella, it will be a perfect amplifier. Knowing that, why in the hell would anyone condone, much less approve, their use?

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Brad White_9 · January 2006

Canadian Population

Population of Canada: 30 million.
(Despite number of cold nights leading to romantic interludes but with dual domestic/heating systems.)

Population of the USA: Approaching 300 million.
(Including tolerable weather that allow us outside once in a while and with dedicated heating systems).

Coincidence?

I think not.

hr · January 2006

I'd like to see you

take a sample to a certified lab and get a written report.

We can speculate until the cows come home! But I, and many others, would like some documanted proof of EXACTLY what you are experienceing. Let us know appromixate cost I may be interested in funding help, as others here should be

The cost of an analysis depends on what you want them to sample for. It can get very expensive if you want them to look for hundredes of "what ifs". Zero in on bacteria or other things they might suggest are harmful to injest or inhale.

Search out a lab first, and find out how they need the sample handled. In the past labs have supplied me with sterile sample containers and special mailers and labels.

I have first hand experience with iron bacteria in a hydronic system. Luckily ir was a closed loop application, because this stuff was very nasty and almost impossible to get out of the system. Smelled like sewage. Which it kind-a is

hot rod

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Uni R · January 2006

Take off eh!

So like uhhhh, Canada would be ummm uhhh like about a billion people just like India eh if we all drank, bathed and cast the ole funeral pyres in the Ganges like they do there eh... instead of just 35 million frozen northerners all basically huddled up along the US border eh?

BTW, Alberta doesn't speak for Canada... yet. Not until Monday after the election. ;-)

Brad White_9 · January 2006

35 Million??

Where did that last five million come from? Hockey season is not over yet and last summer's production is still in the oven so to speak

Alberta (custom tee) Rules.

All in good fun, eh?

Christian Egli_2 · January 2006

An orgy at a dating bar somewhere in romantic Canada

This stuff sticks to the mind... I'll be looking the next time I'm in Canada. Brad, Dave, you guys are a riot, but me worry about bugs crawling in my radiator?

- Everything here is squeaky clean and hygienically sanitary thanks to autoclave-hot steam heat. Though I wonder why no one has ever thought of piping domestic water off of the condensate returns?

A refreshing post

Brad White_21 · January 2006

Actually, Christian

here in Boston we do use condensate to pre-heat domestic water. Generally this is when a building uses utility steam (Trigen) from which the condensate is dumped down the sewer after cooling. Passing the condensate through a heat exchanger, pre-heating domestic water, sometimes to setpoint, does a good job of pre-cooling the condensate. Sometimes we use it to heat garages, anything to dump the heat on the way to the sewer. It makes the best of a wasteful situation.

Glad you enjoy the postings! Send photos of the night life would you?

mtfallsmikey · January 2006

Hey Brad White!

I like the idea of using the waste condensate for DHW preheat!..We don't have central steam in Va.,but I bet that is an interesting system. I guess that eventually some of the water treatment processes that we use in commercial condenser/chilled water systems will filter down to the residential market

Brad White_21 · January 2006

Hey Mikey!

What I just LOVE about this business is that what was once exotic at the commercial and institutional level is now commonplace at the residential level.

Imagine even having Tekmar controls 25 years ago on a building that at best had rudimentary electronics married to pneumatics. Now for less than $1000 you can control to tenths of a degree. For less than $100, I can tell my thermostat WHEN I want my house at temperature and not guess at when to start the system to achieve that.

Axiom and Rhomar have allowed residences to enjoy water treatment especially older systems.

Variable speed and ECM motors on fans and pumps... I cannot wait for magnetic bearings (long a staple or our nuclear submarine fleet) to go residential. They are amazingly quiet, essential in Boomers 600 feet down.
Now they are used for chiller compressors, 75 tons starts with 2 amps.

Life is good!

Best,

Brad

Dave Yates (PAH) · January 2006

and that's one reason

why installing something attached to a plumbing system that could potentially throw sanitation history backwards more than 100 years to a time when poor potability quality was the leading cause of death world-wide - drives me to distraction.

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PJO_5 · January 2006

To add to PAH's points...

I have worked in the water/wastewater business for nearly 20 years. I currently am in the "pure water" (there's a discussion!) area of pharmaceuticals.

Most municipal systems may run the Cl2 residual up to about 2.0 ppm...but that is at the feed source. By the time it hits the house, it is usually much less...in the buildings of this site, we are VERY often finding no residual at all in the city water feeding our RO systems. This has come about over the years with the reduction of Cl2 levels to the customer. With this in mind, it adds more to Dave's argument.

Also, it sometimes takes much less levels than qouted above for carcinogens to form. We have them in some of our systems after we chlorinate at 1.0 to 2.0 ppm. One of the factors in this is the presence of vegetative-based compounds, and believe me when I tell you they are in most municipal systems.

Ask me how I know this stuff. Our company spends an incredible amount of $$$ testing ALL of our water systems (city/DI/RO/USP Grade, etc). Too bad I can't sneak one of these samples in... :-)

Bottom Line:

1) Would you drink water after you put a glass of it on top of the range at low heat (or even none) for a week? How about a day? We don't leave food out for a week and then eat it, do we? I sure wouldn't...

2) For the cost of a heat exchanger/pump, some piping and controls, why would anyone NOT separate the two systems? Code or no code, it just common sense IMHO.

Dave, I know you are passionate about this issue...and like CO it doesn't get enough attention because many people get sick and do not see the reason.

My $0.02

Take Care, PJO

Dirk Wright · January 2006

You can get a domestic water bacteria test kit for cheap. It includes a petri dish, the goop that goes in it, instructions for taking the sample, and postage paid envelope. I did my well a while back and of course it has bacteria, I could see it growing right there, but I don't know if I had legionnella. I seem to recall that there were coliform bacteria found, but not E. coli. I installed a UV sterilizer but have not retested. I do know I have bacteria in there since when replacing a small charcoal filter under the kitchen sink, it was covered with slime, aka "biofilm".

I bought a gallon of 35% food grade hydrogen peroxide and I'm going to toss it down my 30", 50 ft deep well and watch it foam like crazy. I bleach the well at least once per year, but it makes the water undrinkable and bleaches our clothes in the washing machine until it all flushes out. I suppose I still need to bleach the system because the H2O2 won't make it into the pipes in the house. blech.

Christian Egli_2 · January 2006

An x-rated idea, no pictures

In Dayton, before our local utility abandoned all its customers on district heat, we had a lot of those condensate fuelled water heaters. Most of the system operated without condensate returning to the heating plant. Since the rates were based on latent heat content, this was essentially free heat for the domestic hot water.

If there wasn't enough condensate to keep up, usually a steam coil would kick in. The domestic hot water being kept in a holding tank with no flue, had little heat loss. No helpless dependence on wacky-priced natural gas. That was then; now we're all hanging by the neck and the utility is pulling on the noose.

No one ever figured out this condensate water was essentially free water to boot... Like bottled water, but free... Think how much we could have saved on the water bill by drinking all this delicious condensate... Well, wouldn't you drink anything that came out of a radiator?

Maybe at Brad's dating bar, but I think Canadians are smarter than me... they mostly trust beer.

Tom R. · January 2006

Legionella, et al

Which is why current code requires no cross-connections between potable water and anything else without backflow prevention... period. Also requires that circulating H/W systems be kept at 140*+ (Legionella survives to 133*) with temperatures reduced at the point of use. We've been sick too often.

bio-contamination in radiant system

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