Copper returns on one pipe steam

thfurnitureguy_4

I have leaking returns that were placed too high (above the water line of the replaced boiler). The plan is to replace and lower the return. I would use part of the originol iron drips at the top, use a brass coupling at the transition, and switch to copper where the return drops below the water line. The question is how much above the water line can I pipe with copper. Is it critical ? I would think that the wet return should be copper throughout but is it ok to pipe into the H-loop with copper as well? Thanks T.

Fred Harwood

Copper

Purists will say that iron is best. And steam headers and equalizers never should be copper. However, copper wet returns are seldom a problem. If your main ends at an el just past the main vent, you can pipe copper to it, even though it is above the water line. The air in the end of the main and in the wet return above the water line has little or no steam in it. I prefer an iron Harford and equalizer.

thfurnitureguy_4

Fred, Thanks. I was looking at the post "Parallel steam boiler connection..." The picture that boiler pro posted was very simular to my set up (only with one boiler and no drop header) My equalizer is iron. I wanted to go copper return up to the equalizer. His is copper up to the header and copper on the return. See any problem?

Fred Harwood

Copper

Just keep it away from moving steam, and away from sections of piping that may develope lots of stress as the boiler cycles and attached piping elongates and shrinks. The stress may rip apart the fittings.

John Barnes

Go with iron the whole way. I never use copper on steam.

thfurnitureguy_4

Why?

gerry gill

I had a customer a few weeks back,

who just happened to be a professor of metallurgy, so i asked him that very question..here was his answer..its never a good idea to mix any kind of metals together, he told me it creates a battery. and that it wont be the copper that the ''current'' attackes..it will be the steel and the iron..so by putting the copper in on the returns you would just shorten some of the life of the other parts of the system..

thfurnitureguy_4

That makes sense. The question is if in the absence of a good electrolite like strong acid or base, is the battery effect more damaging than water is on iron pipe normaly in a wet return setting. Also wonder about the use of brass fittings as a transition coupling between the copper and Iron. Which is easyer for "Harry business owner" to do. I have had good luck sweating copper. It sounds like both will out last the boiler and me for that matter. You are the pro have you seen Iron pipe rotting out at the joint between copper and Iron? If so, how long did it take? I wonder if this is a new thing and time will tell the true story. The Iron returns look to have been replaced in the 1970s and they are all but rusted through at the couplings. Thanks for your Knowlege on this. T.

Dick_3

copper

The only copper piping on a steam system should remain the city water make up.

The people on this site are suppose to be dedicated to the trade. To use copper on any steam system, steam or condensate, is a disgrace. Lets put the engineering and water chemistry issues aside, it is taking the trade away from the trade.

If your a professional in the trade, a wethead, steamfitter, heating and/or plumbing mechanic/contractor, learn to use a 300 machine and the steel pipe will go in as quick as the copper with a reduced material cost.

How about all the undersized steam headers and piping installed using screwed pipe and/or copper. What's wrong with learning to weld and fabricate the headers and piping the proper size, cost effectively, and professional. True professionals learn all the aspects of the trade.

I realize some guys think the copper is cheaper and quicker (why not us ProPress on copper return piping?), but what's wrong with learning the trade. The money is in doing it right; stay away from the low bid work.

Unknown

Taking the trade away from the trade ?

Sorry , but I just don't see it happening , SD . I've installed hundreds of steam boilers , and not once did I find a homeowner installed copper return . Some projects are always going to be too complicated for a homeowner , whether you go with copper of steel .

And your notion of basing who is a " professional " by choice of condensate piping is a wee bit soapboxish . Other than the opinion that it cheapens the trade , do you have any hard facts that make copper a bad choice ?

Dick_3

RJ loves copper

RJ,

My point has nothing to do with the home owner installing copper returns. If he could install copper, he would know to install steel. Just kidding.

In steam systems with out water treatment:
-Copper and steel errode at the same rate due to the carbonic acid in the condensate. You know, when water and the oxygen in the water is heated to produce steam, carbon dioxide CO2 is created, when the CO2 condenses, carbonic acid is formed in the condensate water. Your copper pipe has a much thinner wall thickness than my extra heavy schedule 80 carbon steel pipe. Which is going to fail first? Actually, the copper fittings will fail before the copper pipe because the copper fittings have a lesser wall thickness because the fittings are "stretched" when they are manufactured.

In steam systems where the water is chemically treated:
Different type of amines are used to chemically neutralize the carbonic acid. All amines contain ammonia, we all know what ammonia does to copper - agressive corrosion. With proper water treatment, the copper pipe and fittings will fail and the carbon steel pipe will last a very long time. Also, the agressive corrosion of the copper will emit copper iones into the water, which will cause galvanic corrosion and pitting corrosion to cast iron and all types of steel.

Talk to a piping and/or mechanical engineer, they don't like copper on steam/condensate piping due to concerns with expansion and strentgh, not to mention the water chemistry thing. What if a steam trap fails and lets steam into the return?

Basically, you get less service life out of copper than steel.

Did the "Dead Men" which understood and respected steam systems use copper? How many old steam systems originally used copper? Never seen one. The "Dead Men" respected the trade. Ask Dan.

Think about this, when you explain your more expensive price compared to the "low bidder's" price, tell the customer you use steel because it is better and has a longer service life; there's no short cuts to a proper system.

The only good thing about copper on a steam system is it is worth more money as scrape when we demo. it.

You know rubber garden hose is cheaper than copper pipe, and the hose would work. Would you use garden hose on your return piping?

Keep in mind selecting the right materials for a job is still a small part of what it takes to be a pro.

Unknown

Thanks for the chemistry lesson

But your conclusions don't jibe with what I see everytime I replace a steam boiler . What I should have asked is have you actually seen copper return pipes or fittings fail on a steam system faster than steel ?

I'm not sure of your background , but I've been on hundreds of steam boiler replacements . Almost every one of them has some copper on the returns . On the many where we reconnect to existing copper , I've never seen it deteriorate like you claim all copper will do with steam . Oh , I've seen plenty of steel pipe clogged so bad you would be hard pressed to stick 1/4 oil line throough it .

SD , you ever see a copper convector steam system ? Ever work on steam boiler with a tankless coil ? A sidearm coil ? A steam heating coil in an air handler ? Did the steam adversly affect any or every system you see with copper connected to it ? Do the boiler maunfacturers you deal with specifically rule out the use of copper ?

SD , I have no problems using copper on my steam returns . I have 1st hand facts , not conjecture from piping / mechanical engineers , that support my claims . Could you point to where you found the info about this ? I've in the past done alot of research , but copper and steam is a highly overlooked subject .

You are right , there are no shortcuts when it comes to steam . You can infer offhanded that I am less than a professional who disrespects the trade by using copper for my returns . And I can retort that it is just your opinion , and it's dead wrong . Like your statement to me , ask Dan .

Thank you sir for reading .

bob young

sd copper

and what material do you use for your immersed tankless coils ? cast iron or steel or aluminun or stainless. the ones i have seen have always been " copper "

thfurnitureguy_4

Ok, the problem is where did the C molicule come in to this. Water is H2O hot water is still H2O steam is very fast H2O. Steam when it cools down and condenses, dose not gain the C from the words Cool or Condensate. Are you confusing the waste Carbon from combustion like in an exhaust pipe Because in that case you Have a butt load of by products that are mixed at high concentrations. If my system was sealed (no new water) the O2 and Co2 blead off when heated. So where is this C coming from? My problem is an excess of Fe2O3 on my Fe PiPeS. BTW My system is pure with no Cu or Pb just lots of leaking rusty pipes that are not that old. PS.The garden hose idea is under consideration