connectt a radiant loop directly into my domestic water heater

Dave Yates (PAH)

I've worn a wet suit and a Farmer John whilst diving neath the surface of those lakes, cause it sure is mighty cold when you transfer through them thermoclimes!

Lets see..... Lakes & streams eh? Lots of bugs there, but they don't scare us none. Less'n we drink that lake water eh? Beaver Fever! Sure am glad no one uses surface collected water in this country for potable water :) Yup, Legionella live there too. Kinda tough to inhale droplets too fine to see though and then get them into the deepest recesses of your lungs & even at that, the odds of that water droplet being "loaded" is reduced by the relatively low water temperature.

Nope, surfs up far as I'm concerned!

Now spas, that's a horse of a different color.

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D. Andrews

Radiant and domestic hot water combined

Is there a way to connect a radiant floor heating loop into a domestic hot water heater and still use the heater for domestic hot water? Do I have to worry about contamination from radiat water setting in pipes during summer months? Anyone with expierence out there?

PJO

Two Words...

Heat Exchanger!

Where's PAH? He would explain it with perfect words and wit, but simply put; isolate the radiant. Do a heatloss calculation for the area, and then see if you have extra capacity in the HWH. Don't forget about temperature control (I'll assume your not doing injection?) with a mixing valve if it's needed.

It can be done, but please do it right...don't fall for the "open system" arguement that includes; free cooling in the summer, super duper efficiencies, no worries, blah blah blah.

This is coming from a concerned person with a background in water and wastewater...not a contractor.

Take Care, PJO

Dave Yates (PAH)

No experience needed - bugs welcome there!

Pat,

You're doing ok without me(G).

No, I don't have any experience at installing cross-connected hydronic/potable water systems. All of mine have ALWAYS had a physical barrier to protect the potable system. Never liked the idea of "using" the water and then returning it at some time in the future. Might as well start drinking our own bath water!

That was long before Legionella was discovered, btw. From all of the research I've done and articles/papers I've read about Legionella, there appear to be just a few basic things this ubiquitous, which means it's all around us in our environment, bug needs to be given a new home in an upscale neighborhood ripe for breeding. As an aquatic lover, Legionella can and do live in our domestic potable water systems throughout the world. But they aren't typically present in sufficient numbers to create illness in humans - unless - you're already sick, a chronic smoker or alcoholic and/or your immune system is lowered. In sufficient numbers & inhaled deeply into the lungs, all bets are off & healthy folks can be hammered too.

So, the little stinker looks for nice hosts like cysts of amoeba and other teeny tiny one cell organisms inside which it can hide from chlorine during its ride along the potable highway. Interesting factoid - at temps below 55 degrees, amoeba eat Legionella. As the temp rises above 55 F, Legionella undergo some sort of change and they then consume the amoebas from the inside & use the casing as their nursery.

Then it's showtime. That little one cell apartment can't contain the bustling hord & they burst forth upon the scene. It wants biofilms for food and hiding places, once again hiding from chlorine and hot water flushes; temps between 55 and 133 F with 99 being the "Honey We're Home" ideal temp (think human lung temps - which surround the Legionella with macrophages that so closely resemble amoeba that the Legionella delight in using this body defense mechanism as their newest and greatest high rise condo - if they gain a foothold, your body next turns on its internal boiler, raising the heat. Damn bugs break out their RayBans and slather up with SPF 25! - they love it ; then there's the lack of chlorine in heated water because chlorine dissapates as water is heated; and lastly - stagnation, which Legionella really digs. You can add controls to exercise your pump if that eases your mind, but when it fails, how will you know? Will the total length of the potable and hydronic tubing (combined) exceed 100'? If so, the codes already call for re-circulating. Want hot floors in summer?

Either do this as a stand alone water heater turned to hydronics with a backflow preventer on the potable feed line and two relief valves (the 150 T&P + a 30 Lb'er) or do as Pat said and isolate with a heat exchanger set up for constant circulation (can be done by gravity when potable circ is "off") so there's no stagnation in that shortened potable loop.

JMHO,

PAH


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Wayco Wayne

Good gravy!

I'm going to hide in my basement until that legionella bug goes away. Sounds awful. I have used a flat plate heat exchanger on several occaisions and they work fine. There's a company called Flat Plate that sells them. Phone # 1-800-774-0474.

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Dave Yates (PAH)

Flat Plate location?

Right here in my hometown of York, PA. Nice little hydronic job we are doing for Mr. Flat Plate himself soon to be seen by youse(G). Brand new Danfoss goodie included too!

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Online Sheriff \"Murph\"

HEY !!!

You got stock in that co. or what???/ Boy what a nite when the backhoe digs up the fiber optics to my isp. down in the burg' !!

Riles

That's a keeper

Nice legionella response, as if I expected any less. I had to print that one for future reference.

I see it is all coming together, this whole anti-open-systems campaign is all a ploy. It has all merely been an attempt to sell more "Flat Plate" Heat Exchangers, conveniently located in your hometown.

JUST KIDDING OF COURSE. Although Barry Pack and the folks at Flat Plate do have a nice product.

Well done PAH.

See you on the 23rd.

Riles

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PAH you're obsessed

Next you will be telling us we can't water ski, canoe, or fish without one of those bubble suits on!

hot rod

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