radiant heat system questions

Old 11-05-07, 12:52 PM
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radiant heat system questions

I moved into this house (1 year old) six months ago, and I am encountering some strange things in the heating system. First, it seems that there is automotive antifreeze in the system, which I now know is bad. Should this have been caught during the inspection? Is the proper antifreeze easily distinguishable from the automotive stuff, because this stuff sure looks and smells like the stuff in my truck? (The boiler is also used to heat the hot water storage tank, so I definitely don't want the poisonous glycol in my water if there is a break in the lines)

Second, if it is the wrong stuff, can I drain it off myself and replace it with the appropriate stuff? I live in Fairbanks AK, where -40 every winter is normal, so I definitely want some freeze protection in my lines. Will it do harm to my system to drain it and re-fill it, letting oxygen back in?

Third, the manifolds for the two downstairs zones (garage and bedroom) on the concrete slab each have two lines for each zone. In other words, I have a total of 8 ends, two supplies and two returns for each of the two zones. However, when I call for heat in one zone, one supply for each of the zones gets warm, and the other supply for each of the zones stays cool. All eight ends come out of the slab in line, and I can see where two of the ends are crossed over each other, making me think that for some reason, two of the supply ends were switched, so that when I call for heat in one zone, I am actually heating both zones at 50% capacity. This seems like such an obvious mistake that it makes me wonder if it wasn't done on purpose. Can you think of any reason why they would want to heat both zones at 50% anytime either of the zones calls for heat,and at 100% when both zones call for heat? Or should I just pay to have a plumber fix the mix-up. I would do it myself, but with the crimping tool alone for the PEX being $100, I think I'm just better off having them do it when I have them come inspect my boiler.
Old 11-07-07, 06:05 PM
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I suggest you get a plumber or heat specialist to check things out. If he/she finds it is automotive, try to insure it is disposed of properly.

USUALLY automotive anti-freeze is green & boiler stuff is pink. I don't know if there is any pink ethylene glycol or not.

Just FYI, both are glycols. Non toxic is proplyene & automotive is ethylene.
Old 11-07-07, 07:30 PM
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Also possible that the cool loop is airlocked or has a kink in the tubing somewhere. For an initial consult and advice on how you can maintain the system into the future, a good pro is probably worth the cost.

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