Steam Piping Material & Press Fittings

Wahlheating

All of our hydronic systems are done with type L copper, and Viega propress fittings. We only do a handful of steam systems per year and typically use threaded steel pipe. Viega has introduced us to their megapress fittings, that are a steel press fitting on steel pipe, but they require a different set of jaws, that are relatively expensive, and the fittings are not as readily available. Does anyone have any experience using copper for their steam boiler installs, and for that matter copper propress. Please share any experiences you have had, Thank you!

ChrisJ

Wahlheating said:

All of our hydronic systems are done with type L copper, and Viega propress fittings. We only do a handful of steam systems per year and typically use threaded steel pipe. Viega has introduced us to their megapress fittings, that are a steel press fitting on steel pipe, but they require a different set of jaws, that are relatively expensive, and the fittings are not as readily available. Does anyone have any experience using copper for their steam boiler installs, and for that matter copper propress. Please share any experiences you have had, Thank you!

I'm not a pro, only a homeowner, but if you offered to pipe a steam boiler for me in copper I'd throw you out of my house.

To be honest, if you did it in steel with press fittings I wouldn't be happy either, but at least it's materials designed for the job.

Copper below the water line is ok in my opinion, some don't like this, but no one likes copper above the water line, ever. It has too many problems but the main one is thermal expansion.

Stick with threaded joints and cast iron fittings for the few jobs you do.

Wahlheating

Thank you for your input! When you say copper has too many problems what specifically are you seeing? I see your point that thermal expansion could cause joint issues, I found a post from Dan H. saying that they are stronger than a typical sweat joint, and they make a particular (FKM) seal for steam installation. Most of the steam systems we are working on/ replacing the steel pipe is falling apart, worn out, clogged up, weak, and leaking, that being said I am curious if a copper piped pro press steam system operated at the correct pressure would outlast the steel?

ChrisJ

I have not personally seen any of the problems, but the ones often discussed on here are joints failing. Also the thermal expansion puts more stress on the boiler's block especially if multiple risers are used.

Some feel copper above the water line causes serious corrosion issues and some feel the same for copper below the water line. You'll find some guys do cast iron fittings + steel above the water line and copper below, and others do all steel + cast iron above and below the water line.

My system has copper below the water line and I did a 2" copper equalizer. Everything else is threaded joints with cast iron fittings.

Even if you used steam rated o rings in your press fittings and corrosion is a myth the stress the piping puts on the block when it expands would be concerning.

Wahlheating

Thank you for the info, I will keep the board updated on how the steel megapress fittings work, we are finishing up our first install with these fittings today. There was not much time savings, especially since the fittings were hard to locate. The next one will probably end up threaded, anyone out there welding residential steam?

BobC

I'm also a homeowner and not a pro but I've heard the pro's say welded headers can be a bad idea if not done right. Welded headers can tear a boiler apart if there isn't a provision to let things move during expansion and contraction.

Bob

bob_46

ChrisJ said:

I have not personally seen any of the problems, but the ones often discussed on here are joints failing. Also the thermal expansion puts more stress on the boiler's block especially if multiple risers are used.

Some feel copper above the water line causes serious corrosion issues and some feel the same for copper below the water line. You'll find some guys do cast iron fittings + steel above the water line and copper below, and others do all steel + cast iron above and below the water line.

My system has copper below the water line and I did a 2" copper equalizer. Everything else is threaded joints with cast iron fittings.

Even if you used steam rated o rings in your press fittings and corrosion is a myth the stress the piping puts on the block when it expands would be concerning.

Chris, the risers on your boiler are 14.5" center to center so the boiler will expand .0121" going from 70º to 212º. The steel header will expand .0142" so the piping has to absorb the difference .0021". A copper header will expand .0182" so the piping will have to absorb .0061". I would think that if you used copper in the same configuration as your dropped header it would be fine especially if you sil-fosed the joints. Have you ever watched a 200' long suction line when it goes into hot gas defrost, it grows 4" in seconds and almost jumps out of the hangers. I'm not advocating the use of copper but I think the expansion argument is overblown .

ChrisJ

bob said:

ChrisJ said:

I have not personally seen any of the problems, but the ones often discussed on here are joints failing. Also the thermal expansion puts more stress on the boiler's block especially if multiple risers are used.

Some feel copper above the water line causes serious corrosion issues and some feel the same for copper below the water line. You'll find some guys do cast iron fittings + steel above the water line and copper below, and others do all steel + cast iron above and below the water line.

My system has copper below the water line and I did a 2" copper equalizer. Everything else is threaded joints with cast iron fittings.

Even if you used steam rated o rings in your press fittings and corrosion is a myth the stress the piping puts on the block when it expands would be concerning.

Chris, the risers on your boiler are 14.5" center to center so the boiler will expand .0121" going from 70º to 212º. The steel header will expand .0142" so the piping has to absorb the difference .0021". A copper header will expand .0182" so the piping will have to absorb .0061". I would think that if you used copper in the same configuration as your dropped header it would be fine especially if you sil-fosed the joints. Have you ever watched a 200' long suction line when it goes into hot gas defrost, it grows 4" in seconds and almost jumps out of the hangers. I'm not advocating the use of copper but I think the expansion argument is overblown .

I had wondered this as well.
I have a ton of 15% staysilv on hand but not the guts to do the test on my boiler.

Of course, 0061" is 3 times .0021" and a cast iron block doesn't like to flex, at all.

Jamie Hall

The problem with expansion is not the one shot event -- it is fatigue failure, either in the joint or -- far more expensively -- in the boiler block assembly. Even good steel fatigues, and in the corrosive environment it fatigues faster. It may not get you right away -- indeed it may take thousands of cycles -- but it may get you in the end. On the other hand, something else may fail first!

That said, if the copper is set up so that expansion is accommodated with very low stress, it would work. But that means swing joints or expansion joints which are free to flex. At which point, you might just as well use threaded iron or steel and relax.

I would imagine if the fittings to which the OP refers are able to flex easily, and the piping is laid out so that the result is no stress, it should work.

Dave0176

I've seen steam boilers piped in copper that run 30 years no problem, I also seen copper piped boilers leaking from a lot joints. It's a toss up I suppose, because the guy that pipes a boiler in copper and don't get a leak for 30 years I guess laughs at us for doing all that work installing cast fittings and threaded steel pipe.

I don't care, I'm old school and a traditionalist, it takes skill to pipe a boiler the way I and most of us on here do it. As Dan said a steam fitter once said, "A copper piped boiler is like wearing a tuxedo with sneakers" and it "also takes the skill out of pipe fitting". Basically my pop who's been a butcher by trade for 45 years can sweat a joint, so in essence he'd be able to pipe a boiler.

Also I'm not saying someone who pipes a boiler in copper doesn't know what he's doing, however most copper piped boilers I've run accross have been piped below manufacturer minimums, meaning more then likely he was lazy, or didn't have the proper threading equipment, or most likely he wanted to make a quick buck.

I'll stick to cast fittings and threaded steel pipe and continue to pipe waaay above manufactures minimums. I like not hearing from my customers ever again for no heat. I get great graditude when the code inspectors come in to sign off on the permits and their in awe of the piping!!!

nicholas bonham-carter

Where you have a larger boiler, needing 3 inch risers, and a 4 inch drop header, a welded header, supported from the ceiling, and connected to the boiler with 2 elbows, and at least 1 foot nipples, could save some time and money, without sacrificing performance.
I would be worried about the seals in a steel propress failing with the pipe movement.--NBC

ChrisJ

Hatterasguy said:

Dave0176 said:

Also I'm not saying someone who pipes a boiler in copper doesn't know what he's doing, however most copper piped boilers I've run accross have been piped below manufacturer minimums, meaning more then likely he was lazy, or didn't have the proper threading equipment, or most likely he wanted to make a quick buck.

Even if copper would survive for 30 years, there is no good reason to do it. If you pipe it properly with the required header and riser sizes the cost in copper becomes astronomical. Whatever you managed to save in labor is more than offset in the material cost.

Ever see a 4" copper header? There's a reason for that.

My 2" copper and equalizer + fittings is something I'll never do again. The 5' length of type L copper was painful to buy and the only source I could find at the time was McMaster.

Dave0176

Hatterasguy said:

Dave0176 said:

Also I'm not saying someone who pipes a boiler in copper doesn't know what he's doing, however most copper piped boilers I've run accross have been piped below manufacturer minimums, meaning more then likely he was lazy, or didn't have the proper threading equipment, or most likely he wanted to make a quick buck.

Even if copper would survive for 30 years, there is no good reason to do it. If you pipe it properly with the required header and riser sizes the cost in copper becomes astronomical. Whatever you managed to save in labor is more than offset in the material cost.

Ever see a 4" copper header? There's a reason for that.

I actually priced a steam replacment about a month ago. It was a Weil McLain EG65 installed in 1980, the contractor actually piped it in copper, he ran two 3" copper boiler risers into a 4" copper header, only problem was he took the mains from between the risers. This is all leaking from numerous joints. The boiler looks to be in good shape but she wants to replace it due to age.

Steamhead

Copper header and risers- bad.
Welded steel header and risers- bad.

Neither one allows for expansion.

The only way you can get away with welding is if the risers from the boiler are threaded into the header. The header itself could be welded up, but all joints between the header and the boiler must be threaded to allow for expansion.

j a_2

null
Great post, you said it all

j a_2

Don't know why but the word null cones up when I try to quote...Dave0176, great post.... I agree

jumper

We're all chickens. Even in industrial settings,where there's no litigation threat or archaic codes,everybody is afraid to use flexible piping like soft copper or hose.