Blocking off steam pipes?

cmahrle

We have a two-pipe steam system. Some parts of the building no longer have radiators, but of course the pipes are still there, carrying steam.



Is there a product we can use to block off the steam pipes (supply) by drilling a hole and injecting it, without taking apart the pipes and putting on caps or plugs? I'm thinking something along the lines of a spray foam, maybe, if there's one that would withstand steam. Or can we cut through the pipe and pack it with something? We'd like to isolate the unused sections of the building so we can downsize the boiler.

nicholas bonham-carter

Cutting off radiators

Why not just shut the valves on the unwanted radiators? Spray foam will not be a permanent fix for this. You could see if your boiler could be down fired to match the smaller load.

Is there a need to replace the boiler anyway?--NBC

Bob Gagnon plumbing and heating

Old Valves

will often continue to leak, usually valves can be unscrewed from the pipes, because they are brass and the pipes are steel. Use two big wrenches and some WD40, then cap off the pipe with a threaded cap.

Thanks, Bob Gagnon

BobC

Foam in the pipes

As long as the pipes to the now missing radiators are capped off no steam will enter the pipes. Capping them off at the old radiator site or in the basement would work equally well.



Injecting foam into a working steam system is a very bad idea, that foam will slowly find it's way back to the boiler and cause no end of trouble.



Bob

Jamie Hall

and furthermore...

First off, I second the comments that foam or something of the sort in the pipe is a rather poor idea, for a whole variety of reasons.  If you are going to do it, do it right.



Which is: cap the pipe.  Depending on the size of the pipe and the piping layout, you may find that there are places where you can, fairly easily, disassemble something and thread on a cap.  However, you may also find that your best bet is to simply cut the pipe somewhere handy, thread up what's left and put a cap on it.



A word of warning.  Check the pitch on the pipe.  If it is pitched at all towards your nice new cap, you haven't finished.  Instead of a cap, you will need to put in an elbow 90 degrees down, a drip, and a connection to the wet returns.  Otherwise condensate will get trapped there at the end and cause no end of trouble.



You will now need a main vent at the new end of the steam main, sized like any other main vent.



Cutting off the returns is another story.  Dry returns can be treated the same way as the steam main, only you probably don't really need a drip.  Wet returns depend on the temperatures in the part of the structure without radiators.  If it is warm, just leave them be.



Do not junk the radiators and their fittings.  If you don't need them, chances are somebody on the Wall here would be just delighted to have them and their fittings!

cmahrle

...

Thanks for the quick responses!



We've removed the radiators and capped both the supplies and returns, but the supply pipes still get just as hot. (Does this indicate there's a leak somewhere in the wall?)



The current boiler works just fine, but it's now way oversized for what's left in the building (it's 2,200,000 BTU and well over half of the radiators have been removed). Despite the removed radiators, my gas usage is still the same. My local boiler guy says that that will be the case until I have a smaller boiler. He reduced the gas flow so I have a smaller flame, but that didn't have much of an effect. He offered to take sections out of the current boiler, but wouldn't guarantee that it wouldn't leak when he was done (two companies told me the same thing).



I agree that foam doesn't *sound* like a good idea on the surface, but wasn't sure about that fire block foam that's supposed to be good to about 400 degrees.



Regarding saving them for someone to reuse: I WISH I could find those people. I've put them up for free on craigslist, but never any takers. They end up going to recycling. (They aren't the decorative type, but still seems like someone would want them.) When we have the next batch, I'll try here.

ALIGA

Calculate your radiator edrs

And post some pics of the boiler.



We can then advise on a solution to reduce heating expense.

nicholas bonham-carter

What will be the use for the rest of the space?

Will you just leave the rest of the space completely empty? Surely there must be some use for the space, which could require heat at some time.

Possibly, your system was , and still is unbalanced, and that is the cause of the excessive bills.

Post some pictures of the boiler, and we may be able to help you reduce your consumption, without resorting to extreme measures such as section removal, or burner modification.--NBC

cmahrle

EDRs of remaining radiators

is 988.

cmahrle

Remaining space; pics

It is an apartment building. We are renovating one section at a time. As we do, we will install individual gas furnaces and remove the radiators. We have reached the point of radiator removal in a number of them (hoping to save heating $), but the new furnaces aren't in yet.



The building has four floors and is about 40,000 sq. ft. (excluding basement). It was built in 1930. The entire first floor is commercial and all radiators have been removed (except one radiator at the main entrance). Above that, each floor contains apartments and each floor has exactly the same floor plan. So as we get a column of vacant apartments (for example, 2C, 3C, 4C), we are renovating them. Of course, we then have a "column" of apartments with no radiators.



I'm happy to take pics. What would you guys like to see that will help with your diagnostics?

nicholas bonham-carter

Hind sight

What was the rationale behind spending an extra 5-10 k per unit on new furnaces, when you already had a functioning heating system in place?--NBC

cmahrle

... is 20/20?

First, we want the tenants to pay for their own heat. (I know there's a way to meter usage in a central boiler system, but we don't want to deal with that, especially considering point 2 below.)

Second, we want to put central AC in all the apartments. When we do that, it isn't that much more expensive to put in a gas furnace instead of an air handler. (Actually, with the gas company rebates, it's a bit cheaper.)

MDNLansing

Pressure

This is going to get real expensive towards the end of your remodel. Running a boiler of that size for 5 or 6 radiators is not going to be cheap. Even filling the pipes isn't going to matter. You still have to get the water up to boiling temp and generate steam. Once steam is generated your run time will reduce a little with less radiators, but the money is spent getting up to that steam point.



You might want to try installing a good vapor stat and running with as few oz of pressure as possible. For only a handful of radiators, you might be able to get by with 4 or 5 oz of pressure. This would help some, but not much.

Steamhead

Which means

you now have combustion equipment in the tenant spaces, instead of having it locked away in the boiler room where no one can tamper with it.



And if something goes wrong in one of those tenant spaces, it can result in carbon monoxide poisoning. This happens more often than most of us realize.



I wouldn't want to live in your building.

cmahrle

Exactly!

> Running a boiler of that size for 5 or 6 radiators is not going to be cheap... You still have to get the water up to boiling temp and generate steam.



Exactly! Which is why we're downsizing the boiler. (Did you happen to read my first two posts in this thread, or did you just jump in on the last one without all the relevant information? Gas usage not decreasing substantially was already covered and is the reason we're downsizing the boiler. Either way, thanks for your input.)

mcsteamy

If I had to guess

Not that I really want to assist with this sort of silliness, even if I understand the rationale (which is seriously, seriously flawed, but a topic for another time).  Oh, well.  You've already done a lot of the damage. 



If the pipes are capped off and still getting hot, you probably have a leak somewhere, or steam short circuiting from the supply to the return.  I have a number of capped off pipes in my system which once covered about 5000 square feet.  They don't get hot, and they're just capped in some instances with crappy plugs that were inserted when some dimwit cut the pipe with a sawzall.  Plugs are like this: http://www.petersenproducts.com/143-3_pipe_plug.aspx. 



Should you do this?  Probably not.  I have no idea what would happen if steam hit one of these pieces of junk.  Note:  Where they did this in my system, the plugs never get hot because, well, the pipe is plugged.

cmahrle

Thank you!

Yes, capping is what I feared was the only way to go. Just thought I'd look for other alternatives, since some places are fairly difficult to get to. Thank you for your help!