Copper Steam Pipe Leaks

I had a local plumber upgrade my steam heat system about 10+ years ago and he used an iron pipe riser from the boiler (about 2.5') and then used copper supply pipes from the riser for about 3' in each direction to link to the existing iron steam pipes. Those copper pipes have various "weeping" leaks that get crudded over with white deposits, destroy the fiberglass insulation and cause rusting at the base of the boiler. Question: Should I (can I) try to solder over the weep points to fix the leaks, or bite the bullet, remove the copper and install iron from the boiler to the exisitng iron pipes???? I'm pretty handy, but I'll probably need a plumber for the iron pipe work.

Thanks!

I've never worked with steam, but since steam is just heated water, I'm sure the same rules would apply. Once water has gotten into a joint, the flux is gone and can not be replaced with the joint assembled. You can not just add new solder on top of the old. You have to disassemble the joints, completely clean the pipe and fitting, flux, and solder as a new joint. It would most likely be easier to just buy new fittings as cleaning the old solder out of tees, elbows, couplings, and etc., while possible and acceptable, is time consuming and hardly worth the effort. The pipe ends are much easier to clean. The old solder does not have to be removed to bare copper, just made smooth so the fitting will go on. Emery cloth is helpful as well as the wire brush donuts.

Thanks for the reply, Gary. You're right, ripping out all the old copper and starting over is the best solution to my current problem. But the longer term question remains: Is copper pipe smart for steam heat supply piping or, since I'm going to start over anyhow, should should I go with iron pipe?

Can't answer that one. I don't know why copper would not be a good choice, but you'll need to get a pro's answer to be sure.

The different types of copper are rated for certain pressures and temperatures. I dont know the length of time, but its at least 30 years. If you go above that with temperature or pressure, you reduce coppers lifespan. For steam, I'd also consider brazing the joints, as its a much more solid way to connect copper(used for underground work in a lot of residential/commercial here).

Perhaps sticking with iron pipe would be best, since its damn thick, and easier to join(only need a threading machine vs copper stuff).

The other problem which doesnt seem to be mentioned is the joint between the copper and iron...is there a dielectric union there? If not, that could be causing corrosion.

Hope this helps!

Residential steam? Running less than 1lb pressure? Type M coppers fine. If the joints aren't leaking too bad, throw a can of boiler seal in it and forget about it.

Dissimilar metals will corrode when in contact with moisture and any impurities, and I think that's what's happening.

First, my thanks to all. No one has said copper is not a valid solution for steam pipes, so that's a good thing. To seaofnames, there is no dielectric coupling that I can see. Also, the leaks are at the copper/iron joints as well as copper/copper. Lots of crud all over the joints. The more I look the more I think maybe its' just lousy solder jobs that have gotten worse over time. I'll try Peter's suggestion to add a can of boiler seal and see what happens. If that doesn't work maybe I'll buy new copper fittings and try to do a better job of soldering that the plumber did. I can't tackle brazing and I don't want to go through the expense of going back to iron pipe. I really just want the very minor leaks (I never see any water, just rust stains) to stop killing the pipe insulation and rusting the bottom of the boiler. My thanks, again, to all.

You are definately going to have to install dielectric unions where there is an iron/copper joint. No amount of boiler seal will help that.

Since it will be shut down anyway...redo all of the copper/copper joints as well. Just heat it up, pull it apart, clean the joints, flux and solder again! Make sure to wipe up any excess solder and you will be good to go after a pressure test(whatever is recommended by the manufacturer for steam).

We don't use dielectric on copper to Cast fittings for steam. Any leaks found will be improperly made joints. How often do you see dielectric fittings on any boiler system? Never, and we transition from steel, CI, malleable to copper all the time.

Steam pipe leaks !

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