Main vent replacement? (pics)

David_14

First winter with this house built in 1874, and thus just learning about steam heat. Bought and read Dan's We Got Steam Heat! Loved it. Never thought I wouldn't be able to put down a book about steam heat. Go figure!
Pretty much all my radiator vents hiss. Heard a tiny bit of knocking for the first time tonight, though the heat has been on for about 2-3 weeks. One pipe system. Five tube hot water radiators (using steam). I looked at the main vents in the basement and they don't seem to be working at all. I'll try boiling them in vinegar as Dan recommends, but want to have some new ones handy in case they can't be salvaged. I realize they're not cheap. I'm unsure how to size them, short of measuring the whole system. Can anyone advise me? I'll attach some pictures.
I also plan to pitch my rads, insulate my near boiler piping, wrap the asbestos, and adjust the pressuretrol.
Finally, I would love to find a steam pro in or near Concord, NH. Nothing turns up closer than about 45-60 minutes using Find a Professional. Any leads?
Thanks for whatever wisdom you can share.
--David

lchmb

One suggestion

There is a gentleman at Johnson and Dix oil company in the Epsom office. Although you would have to be a customer of their's he is very knowledgable in the area of steam. Would try him, Name is Skip. Last I knew he was the salesman there. If you don't do buisness with them he may be able to steer you in the direction of someone down that way who could help you out...Good luck!!..:)

Steamhead

Those vents look pretty small

If you measure the length and diameter of both steam mains we can tell you what you need. I'm assuming the insulation on the pipes is 1-inch thick, this is fairly standard. Measure the outside diameter of the insulation and subtract 2-1/4 inches and that's your pipe diameter. Be careful not to touch the insulation if it's old, since it may contain asbestos.

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DanHolohan

Glad you liked the book.

And thanks for the kind words. Try calling or emailing the listed pros. That may not be too far for them to travel.

David_14

Size of mains

First, thanks for the speedy replies and good advice. I'll follow-up on those pro leads. Thanks. And yes, I thought those main vents looked pretty small too! I spent some time diagramming and measuring my system. A good exercise to learn more about it. There was evidence of radiators being added on after the system was first installed, which supports my guesses about which rooms were added on at later dates.
I am uncertain exactly which pipes to measure when you say measure the mains. My best guess is that it does *not* include the vertical piping coming out of the boiler, any of the horizontal pipes that lead off of the two primary ones going around the ceiling of my basement, the vertical rising pipes that go up to my radiators, or the vertical piping below the main air vents along with the Hartford loop. If this is incorrect, please let me know and I'll add up the rest of the measurements and post them.
I am attaching 2 pictures (diagrams) of my system... One shows what I measured and one shows the entire basement part of the system (i.e. no risers to the rads, or rads). Here are my measurements:
Main 1 = 497" @ 2.5" O.D. *plus* 503" @ 2" O.D.
Main 2 = 527" @ 2.5" O.D. *plus* 245" @ 2" O.D.
The smaller diameter (0.5") vertical pipes (nipples?) leading to the main vents are 6" and 5" respectively. There are 8" and 9" clearance above these, not including the main vents now in place. I am guessing that these dimensions will be important if there are choices when selecting the physical size (not the venting capability) of the main air vents.
Thanks again for your help!
--David

Dale

Vents

Sure, make certain the pipe is pitched correctly from the boiler and then get some new main vents. Also, the picture may be deceiving me but the close nipple on the hartford loop looks to be above the boiler water line, it should be 2 inches below. Since your boiler looks to be a recent replacement and the hartford loop old this isn't and unusual problem and can cause water hammer.

David_14

Hartford loop close nipple

Good eyes, Dale. If I understand correctly what the "hartford loop close nipple" is, then you're right. I just measured it. Water line marked on the boiler is at 27", and so is the junction you mention. Please see the black arrow in the attached pic to make sure I am looking at the right thing. Since there is an old joint above it, it looks like whoever installed this new boiler ~2 years ago didn't do it correctly.

Since the boiler should probably be raised anyway because of some springtime basement water seepage, I am thinking this might be the route to go using at least a 2" block. I got an estimate of $490 for this recently. Guess I can kill two birds with one block. :-) Add that onto the chimney liner and new oil safety tank. I did expect this to add up. Thanks for catching that for me. Hopefully I'll end up with a reasonably trouble-free system after catching up and keeping up with maintenance. I suspect the previous owner didn't do much maintenance.

I am also still hoping that someone will be able to advise me on main vent sizing based on the dimensions I provided. And I'm curious if anyone knows what those bulges are in both of the pipes below the main vents. Thanks again!

--David

Steamhead

You measured the right pipes

those are some long mains, so they need serious venting. I'd use a pair of Gorton #2 vents on each main. This will get the steam to the ends of the mains in a hurry!

The bulges in the drips below the main vents are probably unions covered with asbestos.

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Unknown

Steamhead , you think he might need

to increase the nipple size going up to the main vents to vent the air faster ? They look like 3/8 inch .

Steamhead

Good eye, Ron

if they're that small, I missed it.

David, you should come up off your mains with 3/4-inch nipples, then install 3/4x1/2x1/2 tees to mount the vents. If there are bushings in the existing holes, remove them and get new ones in the proper size if needed.

If there are no bushings you or a pro will need to drill and tap 1/2" pipe-thread holes in the sides of the tees (don't disturb the asbestos when doing this) then elbow up to the second vents.



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David_14

Yes, they are that small

> if they're that small, I missed it.

>

> David,

> you should come up off your mains with 3/4-inch

> nipples, then install 3/4x1/2x1/2 tees to mount

> the vents. If there are bushings in the existing

> holes, remove them and get new ones in the proper

> size if needed.

>

> If there are no bushings you

> or a pro will need to drill and tap 1/2"

> pipe-thread holes in the sides of the tees (don't

> disturb the asbestos when doing this) then elbow

> up to the second vents.

>

>

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 157&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_



Yes, the nipples are 0.5" O.D. (

David_14

Yes, they are that small

They're 0.5" O.D., so it looks like I'll need to upsize them. Thanks for catching it and thanks for the specs on how to do it right.
I think I'll buy a brick now. :-)

"The smaller diameter (0.5") vertical pipes (nipples?) leading to the main vents are 6" and 5" respectively. There are 8" and 9" clearance above these, not including the main vents now in place."
http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=20104&mc=10#Message127889