can you use copper for a steam radiator return?

bbillcee

i have an old black pipe return that was buried under a door that is rotting put...can i replace this with copper? if so is there a problem mixing the metals?

EdTheHeaterMan

The die hard steamers will say not to. But it has been done successfully by many. There may be some issues with dissimilar metal over time but the time is going to be many years. Then it is the next guy's problem. That is why you want to get black pipe and fittings (not galvanized) just in case YOU are the next guy. Seems like the Black Pipe will insure that YOU are not the next guy.

Jamie Hall

Shouldn't be a problem... I hope... having done that a few times...

EBEBRATT-Ed

@bbillcee

The general rule is copper is ok below the boiler water line. Above the boiler water line it should be black pipe.

But sometimes you do the best you can. Certainly the steam near boiler piping and the steam mains should not be copper

EdTheHeaterMan

Jamie Hall said:

Shouldn't be a problem... I hope... having done that a few times...

@Jamie Hall says it's ok... then it's ok. He has done this and he is still at the location where he did it... so he IS that NEXT GUY!

...and hs has over 7 times more posts than me!

JUGHNE

Concerning the dissimilar metals, many suggest a brass valve between the copper and black iron....at each end.
IIWM, I would add a hose bib in the copper at each end. Then you could flush the line and see what might be in there after a few years.

bbillcee

thanks guys, here some pics of the mess!

delcrossv

Threaded brass pipe?

EBEBRATT-Ed

Those elbows should be taken off and replaced with tees. When you drop under a doorway your also supposed to pipe over the door for a vent. But if it heated well before i guess you can skip that.

I wouldn't hesitate to use copper there. You should put something around the pipe under the floor to prevent corossion.

mattmia2

What happened to the pex discussion? Seems that pex would be rated at far more than 30 psi at 212 f and would solve a lot of ground and masonry contact problems in a wet return.

JUGHNE

Can you explain the piping on that radiator in the picture?
Does it heat well?
Where does the pipe on the left side go to?

KC_Jones

Ok, this is weird to me. There is a bottom connection feeding from the top, there is a top connection feeding from the bottom. This is the basement, that's a wet return.

That entire rad, or a large portion of it, has to be below the boiler water line, unless the boiler is in a deep pit? Even so, the radiator connections make no sense.

For the original question I'd do copper on that, and the aforementioned tees (for me for cleanouts) all day long. I'd also install it in such a manner that if more of the other run rotted out, I could easily replace it. Either unions, or running the copper above ground a short distance as it's easier to cut later.

ethicalpaul

mattmia2 said:

What happened to the pex discussion? Seems that pex would be rated at far more than 30 psi at 212 f and would solve a lot of ground and masonry contact problems in a wet return.

I can't find ratings for anything higher than 200 degrees, but it's OK for 80psi at that temperature so I would think it would be fine for any wet return, especially a buried one where the ground will act to cool it.

Jamie Hall

I've never seen a reference to PEX being able to withstand anything over 200 F. One has to remember that the strength doesn't fall gently and gracefully with temperature... things melt or begin to deform very easily.

ethicalpaul

OK what is the temperature of a wet return? I think I'd bet it's well under 200 and now I must check

Jamie Hall

ethicalpaul said:

OK what is the temperature of a wet return? I think I'd bet it's well under 200 and now I must check

Should be well under 200. It might be warm... but not much more than that.

mattmia2

I guess the issue might be if something goes awry and it ends up dry and full of steam.

bbillcee

JUGHNE said:

Can you explain the piping on that radiator in the picture? Does it heat well? Where does the pipe on the left side go to?

My great uncle Had the house built in 35, my father bought it off him in 66 and I bought in 2006 .. the story was that this configuration was taken from “popular mechanics” back in the day… it’s simply using the return hot water to put out some additional heat with the radiator hooked in … does the radiator get hot? Yes not burning but it puts out heat … I’m not a plumber but it seems to work🤷🏻‍♂️I would assume the rad has to fully fill up with water before it returns to the boiler… I have question That maybe someone here can answer… how much water actually raturns? A gallon? 5 gallons? 10 gallons?

EBEBRATT-Ed

@bbillcee

It depends on how much condensate come back through that pipe.

JUGHNE

Heating with steam condensate returning.

That rad would stay full of water up to the height of the boiler water line.
It is part of the wet return system.

All your wet return lines below the boiler water line are always full of water.
It sits in the pipe and part of your radiator until some more is added to the end where the pipe drops down from the heating main.
Add in one end and it flows out the other end.

That is why maybe it might be good to replace all the wet return you have, if practical. Nasty water sits in it all year long.
It is like a trap under the sink.

ethicalpaul

mattmia2 said:

I guess the issue might be if something goes awry and it ends up dry and full of steam.

If your wet return is dry and full of steam you have bigger problems

Jamie Hall

ethicalpaul said:

mattmia2 said:

I guess the issue might be if something goes awry and it ends up dry and full of steam.

If your wet return is dry and full of steam you have bigger problems

Like... much bigger problems!

On the return water question -- that's not hard to figure out. Every 10,000 BTUh that the boiler is putting out will result in about 1.25 gallons of condensate per hour. We usually think in terms of gallons per minute for water flow -- but for condensate we are talking fractions of a cup per minute!

KC_Jones

Interesting idea, I’m guessing there is a drip off the main that feeds the condensate into the bottom.

I can’t imagine how much crud must be in that thing.

Has it ever been flushed out?

mattmia2

KC_Jones said:

Interesting idea, I’m guessing there is a drip off the main that feeds the condensate into the bottom.

I can’t imagine how much crud must be in that thing.

Has it ever been flushed out?

Since it doesn't appear that there is any way to do that without a fair bit of surgery, i'm going to go with no.

bbillcee

mattmia2 said:

KC_Jones said:

Interesting idea, I’m guessing there is a drip off the main that feeds the condensate into the bottom.

I can’t imagine how much crud must be in that thing.

Has it ever been flushed out?

Since it doesn't appear that there is any way to do that without a fair bit of surgery, i'm going to go with no.

the original returns failed in 1980 so that when this stuff was put in and its never been flushed

jumper

bbillcee said:

JUGHNE said:

Can you explain the piping on that radiator in the picture?
Does it heat well?
Where does the pipe on the left side go to?

My great uncle Had the house built in 35, my father bought it off him in 66 and I bought in 2006 .. the story was that this configuration was taken from “popular mechanics” back in the day… it’s simply using the return hot water to put out some additional heat with the radiator hooked in … does the radiator get hot? Yes not burning but it puts out heat … I’m not a plumber but it seems to work🤷🏻‍♂️I would assume the rad has to fully fill up with water before it returns to the boiler… I have question That maybe someone here can answer… how much water actually raturns? A gallon? 5 gallons? 10 gallons?


It's an interesting condenser. No need for traps?

JUGHNE

It is something that an article in "Popular Mechanics" was the idea for this.
Once upon a time people would do things like this.
Say, change the pulley speed for heating to AC etc.
Thermocouple change outs were just something any guy could do.
I had some Handy Man books from that era, it was surprising what projects the homeowner would take on.

And the next generation would learn to do the same type of things.

Today they are challenged to change the furnace filter.

Some literally do not know if they have 2 heating units or where they are.

bbillcee

JUGHNE said:

It is something that an article in "Popular Mechanics" was the idea for this.
Once upon a time people would do things like this.
Say, change the pulley speed for heating to AC etc.
Thermocouple change outs were just something any guy could do.
I had some Handy Man books from that era, it was surprising what projects the homeowner would take on.

And the next generation would learn to do the same type of things.

Today they are challenged to change the furnace filter.

Some literally do not know if they have 2 heating units or where they are.

lol very true!

Hap_Hazzard

You probably already know this, but you'll want to use type L copper.

bbillcee

Hap_Hazzard said:

You probably already know this, but you'll want to use type L copper.

yes! thx

BobC

Has anyone tried boiling some PVC pipe in a saucepan to see how it reacts to 212 temperatures? Don't let the wife catch you doing this.

Bob

Hap_Hazzard

BobC said:

Has anyone tried boiling some PVC pipe in a saucepan to see how it reacts to 212 temperatures?

I haven't, but the rated maximum working temperature is 140°F. That's even less than PEX.

Copper lasts forever as potable water piping. If fresh water in all its varying compositions doesn't hurt it, it should be fine for condensate, which is basically distilled water with a lot of dissolved iron.

pecmsg

bbillcee said:

JUGHNE said:

Can you explain the piping on that radiator in the picture?
Does it heat well?
Where does the pipe on the left side go to?

My great uncle Had the house built in 35, my father bought it off him in 66 and I bought in 2006 .. the story was that this configuration was taken from “popular mechanics” back in the day… it’s simply using the return hot water to put out some additional heat with the radiator hooked in … does the radiator get hot? Yes not burning but it puts out heat … I’m not a plumber but it seems to work🤷🏻‍♂️I would assume the rad has to fully fill up with water before it returns to the boiler… I have question That maybe someone here can answer… how much water actually raturns? A gallon? 5 gallons? 10 gallons?


Do you need the heat there? Or I should ask Do you need to waste the fuel keeping that rad hot?

Is that the condensate coming down to the left? Is yes can you run it closer to the ceiling until your past the door?

ethicalpaul

Copper lasts forever as potable water piping. If fresh water in all its varying compositions doesn't hurt it, it should be fine for condensate, which is basically distilled water with a lot of dissolved iron.

If "forever" is 5-50 years, sure

mattmia2

ethicalpaul said:

Copper lasts forever as potable water piping. If fresh water in all its varying compositions doesn't hurt it, it should be fine for condensate, which is basically distilled water with a lot of dissolved iron.

If "forever" is 5-50 years, sure

About half of mine is about 70 and still in good shape and it has spent its life in ann arbor water that turns brass screws and washers to powder.

JUGHNE

Pecmsg, you are thinking that cond rad is wasting fuel?

True, but I can see benefits to a little heat in the basement.
Especially if the piping is insulated.
Less waste heat than what sits in the boiler when not firing.

It is probably a sludge collector though.
Keeping sludge out of the wet return and boiler.
I can see it causing slow condensate return eventually.

Would have been handy to have a drain port on the other lower tapping.

And I though it would be full only up to the water line....wrong....it has to fill completely up to spill out of the top connection.

ethicalpaul

mattmia2 said:

About half of mine is about 70 and still in good shape and it has spent its life in ann arbor water that turns brass screws and washers to powder.

Congrats! I had the same experience in Michigan when I lived there, but google "copper pinholes"

pecmsg

JUGHNE said:

Pecmsg, you are thinking that cond rad is wasting fuel?

True, but I can see benefits to a little heat in the basement.
Especially if the piping is insulated.
Less waste heat than what sits in the boiler when not firing.

It is probably a sludge collector though.
Keeping sludge out of the wet return and boiler.
I can see it causing slow condensate return eventually.

Would have been handy to have a drain port on the other lower tapping.

And I though it would be full only up to the water line....wrong....it has to fill completely up to spill out of the top connection.

If the heats NOT needed in the basement, then yes, it is wasting fuel, just like uninsulated pipes. If they want the heat thats fine.

PC7060

It would interesting to looks at the rad through a FLIR camera to see how far up the sludge has accumulated. 

I have to admit the multiple elbows and reduction in size of the return makes me uncomfortable. At some point it’s going to completely fill up and present a puzzle/headache to someone.  

IMHO, I’d follow @pecmsg advice and route the pipe as it comes down the wall with a 90 to go over the top of the door and then over to the boiler. 

The radiator is not capturing free heat, the boiler will have to replace that energy during the next cycle.  I admit the residual heat would likely be given up to the boiler room regardless doesn't impacting operating cost. Just shifting where the residue energy in the condensate gets dissipated. 

If you want to heat that room you can do a hot water heat off the boiler below the waterline as I’ve seen people discuss on the forum. Seems like it was refer to as a “Bronx” or “Brooklyn” system. 

 

JUGHNE

That pipe may be a separate return??

PC7060

Good point.  I see the larger (1-1/4”?) line come down and into the lower radiator inlet and come out the upper port on opposite side and down into what looks like a tee to a smaller 3/4” line that returns to boiler on one side and wraps around corner other side. 

Is that a second smaller condensate return?