Re: Replacing shut off valve on the water main line
Posted by iGreg on 2017/9/14 13:24:25
Steam is moisture and moisture causes rust, there is plenty of air inside those old pipes that would certainly constitute enough oxygen (and in fact does).
Your science is rusty. Moisture doesn't cause rust, oxygen does. Moisture simply enables the oxygen to react with the iron to form iron oxide: rust. In a closed heating system like steam or even baseboard, there's no source of oxygen. Almost no fresh water with O2 is let in. This is why potable water systems that have fresh water running through them all the time NEVER use black pipe, only galv or copper. But even a baseboard boiler has everything but the actual risers and radiators black pipe.
Does the word sediment work better for you?
Also I should have clarified that using copper piping would only replace the level return pipes back into the system as this is where years of sediment builds up and black pipe is much more prone to this 'sediment' than thick copper pipes.
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