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system questions

chelly Member Posts: 3
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.


  • Al Letellier_9
    Al Letellier_9 Member Posts: 929

    I was in your neck of the woods last summer and I envy you....at least in the summer. What an amazing place Alaska is !!!
    As to the antifreeze, you should have it tested. If it is indeed automotive stuff, it is a hazardous waste and needs to be disposed of properly. Make sure you have a backflow preventer on the feed line to the system or at least have a closed valve to prevent cross contamination. If you have to change it, it will be an involved process as it needs to be COMPLETELY removed from the system, you will have to flush it and then add the proper solution. As well as the mixed up piping, this sounds like a job for a heating pro.
    Good luck and keep warm this winter.

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  • hot_rod
    hot_rod Member Posts: 22,158
    Flush it

    and take it to Jiffy Lube or most any oil change facility. Around here they take small amounts of antifreeze without a charge. I don't know how a homeowner, or even a heating pro could determine what you have in the system. I can tell you the automotive stuff will sldge your system and raise problems with the circs. I've seen wood boiler customers try automotive antifreeze with bad side effects.

    Most car dealerships do oil and fluid changes and recycle the glycol also. Some states have drop off centers that take solvents, antifreezes, etc. Google Alaska Gov.

    PG and EG glycols do blend without a problem as many of the new autos now use PG fluid and it all gets drained into the same container.

    While the system is drained would be a good time to correct piping bugaboos.

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
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