Corrosive and Rusty Water

BruceB

<span style="font-size:12pt">In 1999, during a remodel, my steam boiler was replaced and used to heat the original part of the house. The new Peerless boiler was piped with copper pipe. When getting the boiler ready for winter, I found that the nipple to the drain valve and the nipple to the bottom of the sight glass were badly corroded and collapsed when I tried to remove them with a pipe wrench. Both nipples were black iron. I replaced both with brass nipples. I thoroughly flushed the boiler and fired it up. Now the water continues to be very rusty.</span>

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<span style="font-size:12pt">From what I have read on this “great “ forum, the cause of my rust is the copper piping used for the Hartford Loop and the connection to the original house piping. </span>

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<span style="font-size:12pt">I would like the boiler to last another 10 years, so thought replacing the copper pipe with iron pipe would be the right thing to do. Is it too late to save the boiler? Can I use an additive to overcome the rust?</span> 

jpf321

no rust from copper

it's not to say that you don't have a problem, however, one of the great properties of copper is that it does NOT rust. so look elsewhere for your rust problem.



remember to bring the boiler to steam anytime you add a large amount of new water to drive off dissolved oxygen brought in with new water. do you know how much new feedwater is brought into the system via the auto-feed?



perhaps you have returns that are not copper that could be the source of your rust.



am i reading correctly that you have 2 boilers on the premises?



your hartford loop looks to be quite low. perhaps more pictures of the boiler(s) and pipes may help.

Dave in QCA

Copper and Black or Galvanized Iron Pipe

The rust is obviously not from the copper pipe, because copper does not rust.  However, copper pipe connected to iron pipe, when both are filled with water, will cause the iron pipe to corrode and rust away at a much faster rate.  The copper to iron connection on the steam side, is probably not the source of the rust, but copper should not be used for steam for other reasons.

The iron in your boiler is cast iron, and is not as prone to the galvanic action of the copper, but it can still be affected. 

Also, the copper above the water line is greatly affected by the temperature extremes of the steam and the joints will likely fail at some point.  Use of copper piping on the steam lines is never recommended.

Some of the pros on this site do use copper for the return and equalizer piping below the water line.  The copper does stay cleaner than black iron ( to a small degree).  But the stystem overall will be less prone to corrosion and decay if you do not mix copper and iron at all.

BruceB

Some Answers

Thank you for your responses. Here are answers to some of your questions. Yes, I have a second furnace to heat water for the under the floor heating in the newer parts of the house. The bottom of the loop is 28.5 inches above the center of the water level probe. Lastly, I have just replaced the automatic water feeder with a Hydrolevel VXT-24 which has a feed counter. I guess if it shows more than 6-8 gallons a month, I have an additional problem.

From your responses, I don't have to replace the copper piping unless some leaks develop. The black iron nipples must have been the weak points of the system. Did I create an additional problem by replacing them with red brass nipples?

Would you recommend an additive to help remove the rust, or do I just live with it?