Steam Supply Pitch / Copper vs Black Iron

goonsquad

Hi Guys,

I'm new here so be gentle. I'm a homeowner, and am looking for advice with my old steam system. As I'm looking to finish my basement I want to create a powder room (left side of attached image) where the existing toilet and utility sink are. 2 questions as I seek to do so:

1) Is there anything against my relocating the existing supply line (white painted black iron) closer to the facing wall so that it can be put behind studs/sheetrock? This would presumably change the pitch, but still retain a left to right upward pitch.

2) What would the preferred material be? It's hard to see, but the existing yellow section is copper and the green is black iron. I understand that it's usually the joints between Copper/Steel that tend to break due to the variance in expansion. Hence I've heard that copper is generally/more acceptable for return pipes than for supply. Would it be prudent to re-create the same construct, with most of the supply run being black iron, transitioning to copper for the final bend down (far left)? I would presume that at some point, after X feet of run, the returning condensate will have cooled and that the expansion/contraction would be lower.

3) We had our returns replaced with Copper several years ago. To my eyes, the only problem we have with our supply pipes is at the left green section. I spoke to a guy who told me that it was likely the far left "downspout" (not sure the term) became clogged at some point, causing condensate to pool all the way up into the supply lines, thus causing them to rust. This is the whole reason for my looking to replace this green leg and move it over (in addition to moving it closer to the wall.

Thanks in advance,

-Jeff

Jamie Hall

Use black iron for all the steam pipes, or pipes that may be carrying steam. Once you get below the boiler water line, copper is fine. It isn't the joint between copper and iron that leaks -- it's the solder joints in the copper. They get stressed, and solder joints don't take repetitive stress well.

As to relocation -- if you can do it without significantly changing the pitch, that will work. But... is the proposed relocation the red line? Or what is the red line? And what is the relationship of the height of that red line to the water level in the boiler?

goonsquad

This is very helpful. Yes, my intent is to relocate to the Red Line. It's a little difficult to see from the picture, but the current location is probably 2 feet from the foundation wall, which would make it be running right through the new living space. If I'm understanding correctly, I probably want to make the new pipe location stay above the water line, with a similar left-right upward pitch. At some point, of course, it goes vertical, back down to the return pipes.

Another thing I'm just now considering is that the current green section in question no longer has radiators above it. The last was removed, with the room in question being serviced by the opposite side steam supply.

So presently, the ONLY radiator being serviced by this section is just right of the rightmost portion of the Red/Green (far right of picture". I'm not sure if that changes things.

Jamie Hall

goonsquad said:

...

So presently, the ONLY radiator being serviced by this section is just right of the rightmost portion of the Red/Green (far right of picture". I'm not sure if that changes things.

It does. If there are no radiators being served on the rest of that line, and it were mine to play with... I'd extend the steam main about a foot and a half past the last runout, put a nice main vent (properly sized!) on a T about a foot from the last runout, and then at the end turn it down to near floor level and hook it up to a convenient wet return somewhere. If there's no other radiators, and no other drips (vertical pipes down) involved, there's no good reason to take it all the way across.

I can't see the rest of the system, but you might end up not having any heating pipes in that new powder room at all...

goonsquad

This is great. So by cutting the supply line short, let me make sure I'm getting this right

1. I'll move my radiator a couple feet right. I want to do this so I can drip this supply right of the pictured window
   
2. I can T a #1 vent left of that
   
3. And last I can have an elbow with drip back to the existing return pipe
   

If I have this right, and I can somehow get it to fit in this corner, this will be perfect.

Jamie Hall

That ought to work. Be sure to get the pitch on the new runout right...

goonsquad

The existing runout (assuming you are referring to the pitched copper pipe closer to the floor that returns the water back to the boiler) is what we'll tap into with this new drip.

So when we say that I should take black iron down to the water line, do you mean that in the literal sense?

So if my water line was at 40" high, my vertical drip would have a copper/black/iron joint at that point? Or would it be ok to take copper to the top of the drip?

Jamie Hall

You could have a joint there. I'd take black iron to some convenient location below the water line, and hook into copper there. Black iron is always acceptable; copper only where it is wet and stays that way.