A few simple question from a newbie

David_53

Hi folks, I bought a 2 story commercial building about 10 years ago and have been struggling to get the steam heating working well ever since.  We have a boiler that is a couple years old.  I bought Dan's books, and have tried to understand how it all works, but I'm not clear on a few things and was hoping to get some advice.



1. Do I have a one or two pipe system? I think it is a two pipe system because there are pipes that take the steam to the different units on the 2nd flood and then there are separate wet return lines that come back to the boiler.  But here is the thing...I have attached a picture that shows the pipe configuration directly underneath the last radiator furthest from the boiler. There is only one pipe that brings the steam to the boiler and then the condensate falls back into the same pipe for a short distance, but is then returned in the return pipe below it.  So I would think this means I have a two pipe system, but I was just puzzled by the fact looking the picture below the steam and condensate seem to share the same pipe for a small distance under the radiator before the condensate is returned to the boiler in the lower pipe. So is this still a two pipe system or some sort of hybrid?  I'm confused? Any thought?



2.  Also, is the grey thing on the top of the pipe a main? The last radiator in the line does not get that hot, despite the fact that I changed the Gordon radiator valve. We have never chained the mains (which I think the grey thing is). Would this be worth changing? Looks like they could be painted, which I know is not good. My question is can someone confirm that the grey device on top of the pipe in the picture is the main? It is at the end of the line.



Thanks in advance for any help!

Dave

David_53

here is another pic of what I think is the main?

here is another pic of what I think is the main? pic should be turned counter clockwise.

nicholas bonham-carter

1-pipe or 2?

are there 2 pipes going into your radiators? probably not, so i would guess your system to be 1-pipe. the main vent at the top of the tall pipe is a main vent, and is probably a bit small for your system. get a gorton#2 to replace it, and reroute the vertical pipe with some elbows to break up any water-hammered slugs of condensate which may shoot up and destroy it. if there are other vents, then they should be renewed as well, and as you cannot have too much venting, put on the biggest. the alternative is to pay the fuel company to force the air out at great expense, and hear complaints from the occupants about uneven heat. the radiator vents should be slow, and the mains fast so that steam arrives at all radiators simultaneously

check that your boiler was properly cleaned after the installation [see skimming].

some insulation on the pipes is essential, and could be just wrapped as a temporary expedient with 2 in fiberglass batts. later when you have more time you can do the more professional pipe insulation.--nbc

moneypitfeeder

Take some pics

of your rads, so we can see the supply/return of them. You could easily have a 2 pipe system that has a 1 pipe thrown in. (I've got a 2 pipe system, with the attic that has a 1 pipe rad.) Its kinda goofy to me, but I supposed the dead men saved on not having to run both pipes that far, and on not having a trap.

crash2009

Hope this helps

The photo you sent is definatly one pipe.  I labeled a couple things for you to help you see what's going on inside the pipes.  During the heating season the main has a small river of condensate running through it at all times.  When the condensate gets to the end, it runs or drips down to the wet return.  Then it runs back to the boiler to be re-heated and turned back into steam.  At the same time all that is going on, more steam is being made in the boiler and travelling through the same pipe at the same time.  Steam is faster than water and if you can imagine the steam flying down the main toward the end, it causes ripples and waves in the condensate, and can even pick the condensate up and slam it into the end.  When the steam slams the condensate into the end of the main, the condensate can be forced out of the main vent, which I can see in your photo.  The main vent is likely worn out and needs to be checked for proper operation.  If you can tell us the length and diameter of the main someone here will be able to tell you how many main vents you need.



Someone put that main vent up high for a reason, I have never seen one that high before.  We put them high to protect them from condensate, but it looks like yours got nailed.  This suggests to me that maybe something else is going on.  Maybe pressure too high, or slow/blocked return. 



 

Steamhead

It's a one-pipe system

at least the part in the pic is. If your radiators have only one pipe connected to them, it's one-pipe. But we've seen buildings where some rads are one-pipe and others are two-pipe.



The main vent is up that high to keep it from water-hammer damage. But if the steam pressure is too high, that can also cause a vent to fail.



Where are you located?

David_53

Thank you!

Thank you so much for your reply! I was very impressed by what you did to the pic! I actually do have a slow return and I have the boiler guy coming tomorrow. We may have to change some of the piping.  How much do you think it will cost to buy a new main vent?



Best,

Dave

David_53

Thanks

Looks like the radiators have one pipe, not two.  So now I think I have a one pipe system, what confused me was that the condensate and the steam have two pipes in the basement, but they are connected...as you can see in the pic. 

David_53

Thanks

Thanks!! I'm in Westchester County NY.   How much do you think it would cost to replace the main vent? I was thinking of just taking if off and bringing it to the boiler supply house by me.

David_53

Thanks!

Yeah, my boiler was never skimmed after installation, which I know is crazy. Does it really take a day to skim the boiler?  I need to have it done. But I need to find someone who will do it right. And the company that installed the boiler used a 3 inch pipe instead of 4 which the manual calls for....it has got us by the last couple winters, but I know it is totally inefficient.

Steamhead

Not that simple

we need to know the length and diameter of the steam main. This tells us how much air is in the main that we need to vent. If there is more than one steam main, we need the info on all of them. I'd bet the vent in the pic is too small, which is making your system heat slowly. 

David_53

ok...i have some more info

THANKS!!! I went down and measured. There are two main lines from the boiler. One is 80 feet long and is a 2 Inch pipe...there is just that one main vent you see in the pic above at thethe end. There are 7 radiators that come off that line.Then there is another main line coming from the boiler that has the same vent on it to as pictured above but that line is about 125 feet with 2 inch pipe. I talked to my oil guy and he suggested changing both main vents with Huffman 75's. Does that sound right?

Rod

Main Vents

i think you would probably need more venting than just a single Hoffman #75. The Hoffman #75 has about half the venting capacity of a Gorton #2.  I would go with whatever Steamhead suggests as he is a very experienced steam pro and his estimates of the needed venting are always right on.

- Rod

David_53

hmmm

Hi rod...thanks for the reply. I'm curious to know what he will say.

Steamhead

Vent the long main

with three Gorton #2 vents. Vent the short one with two Gorton #2 vents. This level of venting will make those Hoffman #75 vents look like toys. The Gorton #2 is the biggest main vent made today.



You'll need to build a "tree" of piping to accommodate these vents. The small pic at the bottom of my posts shows one version of this, though the trees come off the side of the main rather than the top as yours do. Some of the other posters in this thread have some vent tree pics of their own, which I hope will show up shortly ;-)

David_53

Interesting

Steamhead, I can't thank you enough for your help! I really appreciate it. I just read your reply...did you mean to say use the 2 Gorton #2's for the long main run? And then use one Gorton #2 for the shorter 80 ft. main run? 

Steamhead

No

you will need a total of five #2 vents. Three will go on the long main, two on the shorter one. This will get rid of the air in a super hurry, at about an ounce of pressure.

David_53

Oh, OK.

Oh, OK. Now I'm clear. Do you think I need to check the pipe below the vent at the end of the main (the one the tree and vents would be attached to? Do they clog? And I it was suggested above to put an elbow before the vent so the condensate cannot shoot up and mess up the vent...do you concur?   I'm thinking about an elbow and a tree at the end of the main with 3 Gorton #2 hooked up.



I wish you were located in NY! Do you know any good steamheads in my neck of the woods? Right outside of nyc?

Rod

Multiple Main Vents

Hi David-   Here's  link to Gerry Gill's Website. Gerry is a Cleveland steam pro who is an expert on venting.   http://www.gwgillplumbingandheating.com/webapp/GetPage?pid=415

Also I've attached a drawing by Brad White showing a setup for multiple main vents. Note the use of a pipe union as this allows you to make up the vents a piping on a work bench and then attach them to the main using one fitting, the pipe union. Gorton #2s are available from Pex Supply on the Internet.

- Rod

David_53

Great

Rod, excellent info. Thank you very much!