Rhonemas said:Apples to oranges. Contamination of wells and open systems have nothing in common. What causes contaminated wells is when the well head is left open, or its seals have deteriorated bugs/leaves get into into the well and die in the water leaving organic rich food for bacteria to feed on and that contaminates your well. An open system didn't cause the contamination, you'd be in just as much trouble closed or open. I personally don't see a problem with open systems, I don't think it any more health risks than closed. My thinking, and I could be wrong is that if there's going to be any bacteria it's going to exist in the hot water tank that's the place it stagnates most, is constantly given fresh oxygen rich water and, won't matter with a system that's open or closed. Even hot water tanks at 140F have a 25% likelyhood of bacteria infection. Everything I see says that the case. As for the cold water, my sister lives in a condo on the 5th floor and cold water goes through 500 ft of PEX before reaching her. I have an open system, and for me to drink cold water it goes through 500 ft of PEX before reaching me. Is there any difference? Sure, mine zig-zags, but we both have 500 ft of PEX so what's the difference? Why aren't all these people in skyscrapers or with plumbing at great distances getting sick? Why is it so common today to have huge PEX runs from each appliance going to manifolds in ones basement if bacteria infestations are so common in long stretches of PEX pipe? That's why I think open or closed isn't going to matter.BrownianHeatingTech said:I was trying to think of a diplomatic way to say this, but I can't... any company advocating open systems for radiant (ie, combining radiant with domestic hot water, with no heat exchanger) is grossly incompetent. Aside from wear on the equipment, all sorts of nasties can grow in the heating tubes during the summer, then get pumped into your drinking water when you fire up the heat in the fall.
I can't imagine anyone professional being willing to advocate such a thing. I went to grade school with a little girl who was crippled by diseases she got from a contaminated well. It's just not something you play around with. Heating water and domestic water are always separate.
Bacteria aren't going to propagate to dangerous levels inside flowing water. The issue with open systems is that the water sits stagnant for months during the summer. Then you fire up the system when it gets cold, and you are dosed with the bacteria. Months of growing time, not the short trip through a PEX pipe inside the house.
Rhonemas said:The Radiantec site, the owner of that company is Bob Starr. He's the one who invented running PEX tubing through a thick insulated slab for heat storage, buffering, etc. which is what we're talking about and he invented it in the early 80's. His design so successful it has obsoleted all others. So, I hope he knows what he's talking about as what we're talking about here, that company he started invented!
That's an amusing notion.
Joe