Hydronic system flush????????

Old 12-17-04, 05:48 AM
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Hydronic system flush????????

Does anyone here know if there is a flush available for a hydronic(hot water) heating system? I find that when I bleed my rads I get some copper/black colored water which makes quite a mess.

If the chemical is available what is the proper flushing procedure?

Have a wonderful Christmas and a terrific New Year.

Old 12-19-04, 05:47 AM
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You can flush with a chemical called 8 way but I think it's more of a treatment than a flush. The best I have ever used is TSP (tri-sodium-phosphate) It is available at Sears hardware and the ratio (I think) was 1/4lb per gallon of water. You should pre-dissolve it and circulate it as the water warms up. Don't get it much over 100 degrees F. Circulate it for an hour or so and then drain it. Add fresh water, heat to operating temperature while circulating and drain again. Fill with fresh water and add the 8 way and you are finished. If you don't flush you may get foaming from residual TSP in the system. I'm not sure you will get all the heavy oxidation out anyway, but you can try. I cleaned and treated the system in my shop that way when I built it 9 years ago and there is radiant and copper finned baseboard and a steel boiler. The water in the system (I can it see through the radiant tubes at the manifolds) is as clean as the day it was put in. When I flushed that brand new system, the water that came out was amazingly dirty.

Old 12-19-04, 06:13 PM
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Thanks for your reply Ken. I would have to believe that after a new system is built that it would be full of acid from the soldering process. My system is about 40 years old and anytime I've had the oppotunity to look inside the system(removing a rad for instance) I have found nothing but black slime, dirt and copper colored residue inside. My system has been flushed many times but I got to thinking that there must be a chemical made for this specific purpose. I'll check out that 8 way stuff and see if it's compatible with my system.

Have a wonderful and safe Christmas holiday.


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