end of riser piping

amateurplumber

i have a1 pipe steam system in an 8 family building.4 floors, 2 apartments per floor there are 8 risers going up through the building. In the apts on the top floor the risers terminate. They all have vents about 1 ft from the top. They actually go about 1" into the ceiling. Because they expand and contract there is no effective way of plastering or caulking around them and dust is always coming down. The collars i bought don't work either, they are not tight enough. I am blowing14" of cellulose into the attic space above to insulate and am afraid of the problem being much worse and it continually coming down into the apt. I thought of shortening the pipes by an inch or so and then they would not protrude into the ceiling and i could close the hole in the ceiling. It seems the only reason they had them go 1" into the ceiling was to give them stability since those pipes can wiggle around by quite a bit. So if i support them from the wall that should take care of that.



Am i correct in my assumption about why they protrude into the ceiling and if so is there any reason i should not go ahead with this plan?



The pipe comes out of a tee off which the radiator is. the pipe in the 3rd floor apt below is 1 -5/8" (actual size) and then these risers all are 2-3/8"( actual size) in that last 10 feet, in the 4th floor before they terminate into the ceiling.



Why do the risers get bigger in size in that last 10 feet of riser? Is it to provide extra heat into those coldest highest apts? Or is it something to do with assisting venting at the end of the line?



The tenants would prefer no pipe at all.



If i remove the pipe i will have removed the end of line vent for that riser -probably out of the question?.And i will be interfering with the volume of the system and may disrupt the balance?

If i shorten it the end of the line vent will be closer to that radiator valve , maybe too close?

And if i reduce the diameter of the pipe am i probably interfering with the venting some other way?



Lastly what is the trick for unscrewing those 2-3/8" actual size pipes. Do i need to apply heat? A small mapp gas soldering torch doesn't seem to apply enough heat.



Any help is appreciated

Rod

High Risers

As a homeowner, I haven't had any experience with a situation like this though I'm sure one of the steam pros can help you out.  As to why the pipe size is bigger on the end of the riser I can only think it might have to do with slowing down the velocity of the steam so that water vapor would precipitate out before reaching the vent. I can think of a couple of questions that might help us figure out a possible solution to the situation. What type and model/ size of vents are on the risers now?  Are there any problems with the vents' present operation....like "spitting", noise etc. ?  Are the radiators on the risers heating properly?  You said the last 10 feet are 2 3/8 inch. How did you get this measurement? Are the 4th floor apartment's radiators connected to this "2 3/8" inch pipe for does it change sizing above them?

I've attached a couple of items that might be of help to you.

- Rod

amateurplumber

high risers

the vents are gorton size D. there is no problem with vents or the radiators the problem is dust coming form the ceiling.

i measured the pipe diameters with a calipers.

the riser form the 3rd floor is 1-5/8". just above the tee to the radiator it switches to 2-3/8"

amateurplumber

high risers

sorry didnt see your attached items till now. so i should be referring to the 2- 3/8" actual size pipe as a 2" and the 1-5/8"actual size as a1-1/4".

and it would appear that maybe i can eliminate the pipe and have just a vent (or 2) instead but surely i would be disturbing the balance of the system which might get rather involved.

Patrick_North

Vestigal Piping

I'm also not a pro, but... Could this be the remnants of a down-feed system? In this type of setup, steam was sent to a supply main above the top floor and fed down risers. I understand this was common in apartment buildings. Presumably you now have a main in the basement? Wet/dry return? I would guess these risers (from the top floor rads that extend barely into the ceiling space) could be removed altogether. You may then want to vent the riser in the floor below or augment the venting of the terminal radiators.

But I may be getting ahead of myself. More details about your system- including pictures- would be helpful to those who know a lot more about the ways of steam than I.

Good luck,

Patrick

Rod

Vents

Sorry about the drawing mix up. I added them as a second thought so that's why you missed them.

Patrick's idea that the piping size change maybe part of an old system has credibility. Let's wait an see what the pros say.  Just for your information a Gorton "D" is a radiator vent  (1/8 inch angle pipe connection) but is the same size (venting capacity ) of a Gorton #1 Main Vent.  What is the type, model /size of the vent that is now on the fourth floor radiators?    As Patrick mentioned you might just try plugging the hole where the vent hole where the vent is now and switch the Gorton "D" to vent the fourth floor radiator as a test.  That might give you some idea of how well the system would work with out the bigger pipe. I can't see that system balance would be that much of a problem due to the change. As Patrick mentioned pictures etc. always help.

As for breaking the pipe joints, you need a pair of big pipe wrenches with possibly a "cheater" to go along with each one.  "Cheaters" are pieces of pipe that fit over the pipe wrench handle to increase your leverage.  My wrench handles fit 1 1/4 inch black pipe and I have pairs of "cheaters" in the size lengths of 24, 36 and 48 inch. Not the best way to treat a good pipe wrench but handy for breaking loose the occasional large pipe.

- Rod

crash2009

Expansion and contraction

is carving a hole in your ceiling and the dust is annoying the tenants.  These steam pipes move quite a bit don't they.  My main lines run through plaster and drywall partitions down in the basement.  I have had a similar problem with the mains rubbing holes in the walls and the dust falling on the floor all the time. 

My solution was to use chimney mortar "Type N" , then prime and paint.  I used this mortar in 3 places, last fall, and today they show no signs of wear.  

This photo shows the ceiling of a basement bathroom.  The insulated pipe you see is the main and a riser going to the main floor kitchen.  This one was always making the basement bathroom sink dusty.  The sink is directly below the riser.  It looks a little rough but it works. 

The heat is working good right?  Dont punish the pipes for the fault of the plaster.

Greg Maxwell

Main Vent

While you have to have to have a vent at the end of the main, there is nothing that I know of that says there has to be any specific length of pipe after the end of the last rad. The only solution that I see here is to shorten the run out on that main. Is that possible? Could you move tat last rad in the unit to accomodate that? That would mean your vent would be in a more reasonable location. Just remember, that vent should be at least 6" from the end of the main to vent properly, and allow that riser to pressurize properly. Some pictures of this would help if you can do it.

nicholas bonham-carter

extra riser purpose?

if this is not a down-feed system, then the only other purpose for these riser extensions could have been to supply extra radiant surface to the top floor. if the radiators are original to the building, then they are most likely sized appropriately to the heat-loss of the top floor room [especially with the insulation]..

quite likely, the system was unbalanced due to inadequate main-line [not rad] venting, and these riser extensions were installed to compensate.

remove the riser with a saw cut above the "t", and pop out the remaining ring from the threads. i would recommend putting a gorton #2 on the top of every riser next to the radiator. in addition, the main vents on the horizontals in the basement should be also gorton #2. the aim is to have steam arrive at all floors simultaneously, without paying the gas company to squeeeeeeeeeze the air out of constipated little main vents.

check the location and setup/anticipation of the thermostat. a honeywell visionpro with remote room sensor located in the coldest part of the top floor will enable you to keep the control panel in a protected area. 

try and post some pictures of the boiler and its piping, as that may also have been knuckle-headed; and you want the potential 30% savings to start at the beginning of winter-not the end!--nbc

Greg Maxwell

Main Vents

I think you are right, and it was added as a band-aid. I also think that you are correct, and a riser vent next to the rad would be a good idea, and vent as fast as possible.

nicholas bonham-carter

removing risers

plenty of venting is needed here, but main-line, not radiator vents, as those should be slower than the mains. simply putting in larger radiator vents will only make the top floor colder again.

one way to tell when venting is adequate is to put on a good low-pressure gauge, and observe the back-pressure during the air escape phase. mine is venting at 2 ounces. when the vents close, and steam has entered the radiators, the pressure will then rise to the cut-out point on the vaporstat of 8 ounces [on a cold day].

if my venting were not adequate, then the pressure rise would be quicker as the gas company would be forcing the air out, instead of letting it escape [where part of the fuel savings come from].--nbc

ChrisJ

Insulation

Another example of Crash2009's excellent insulation job!

Steamhead

"attic space above"

This explains it. They wanted to be able to add radiators to the attic space should that ever be needed.



When venting a system like this, size your main vents at one ounce of pressure using Gerry and Steve's charts. Size the riser vents at two ounces and the radiator vents at three ounces. The steam will fill the mains first, then the risers, then the rads.

amateurplumber

vestigal piping

i doubt it is a down feed system. there is no other evidence of that .this building  was built in 1890 as  a tenement. its in brooklyn  ny. yes we have the boiler in the basement. cant get a better foto for a few days  (thats the radiator behind the curtain).

amateurplumber

vents

the drawings are helpful thanks for adding them. i have gorton "D" vents on the 4th floor radiators

i indeed have 2 cheaters 48" long, still couldnt get it to budge. i will probably take a grinder to it.

amateurplumber

Expansion and contraction

thanks for the info , might resort to that.

amateurplumber

Main Vent

 that radiator has to stay where it is, under the window in the kitchen 

amateurplumber

extra riser purpose?

yeah that theory sounds pretty plausible. the boiler piping is fine , the plumbers who come once a year  for maintenance are very good , said as much and the system as it stands seems to work quite well.

amateurplumber

"attic space above"

there is no eveidence of the attic space being habitable. where can i get gerry and steve's charts?

nicholas bonham-carter

venting charts

go here for that, and get some of the steam books as well: http://www.heatinghelp.com/categories/Books/5/1

the idea is to measure your horizontal steam-supply pipes all the way round back to the dry returns next to the boiler, so you know the volume of air which has to be allowed to escape without forcing it out. i have a 1,050,000 btu system with 6 dry returns, with 3 gorton #2's on each [pex supply.com]. "air is the enemy, it must be chased out like the raccoons from the garbage cans"

for the risers in the 3rd floor section, i used gorton d's on the radiators, but your situation is easier, as you have the open tee's from the additional riser extentions, so you could put gorton #1's on them. as i said before, the aim is to get steam as quickly, and simultaneously as possible to all the radiators. all the rest of my radiators have the early hoffman fixed orifice [40?]. "vent the mains quickly, and the radiators slowly"

the benefit of running at low pressures can not be over stated, as steam moves more quickly at lower pressures than high. a vaporstat is required for this.

even though it may seem expensive for all the vents/gauge/vaporstat, the alternative is much more expensive in the long run. i used my good low-pressure gauge [gaugestore.com, 0-15 oz.], and kept adding vents on an antler until i had the low back-pressure i wanted. that plus a new boiler reduced my gas use a third, and the gas co replaced the meter to double check the new lower consumption!--nbc

Steamhead

Right

they never actually finished the attic off. But they ran the pipe in case they ever needed it- this was not uncommon.



Go here for the venting charts- they are part of an e-book:



http://www.heatinghelp.com/products/Books/5/146/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-by-Gerry-Gill-and-Steve-Pajek

amateurplumber

venting charts

great info . thanks!