Air vent leaking on 1-pipe steam radiator

Jane_7

Hello Heating Help gurus!



We have a problem with an air vent on our kitchen radiator that leaks about 1 cup+ of water per heating cycle; water hammer that happens in the pipes under that radiator; and what sounds like surging/raging water in the steam pipe that goes from the 2nd to 3rd floor of our house.



Some background: We have a one-pipe steam heating system, which was converted from oil to gas about a month and a half ago. Our new boiler is a Burnham pin 4 cast iron steam boiler Model # pin4sni-ME2. The house is from 1915, and I am not sure about the history of the piping as we moved in over the summer and this is our first winter here. We did some renovations when we moved in, including moving the kitchen radiator to an interior wall from an exterior wall; we also had to move a steam pipe that goes up from the 2nd floor to the 3rd floor over a few feet.



Everything seemed great at first the first few weeks after the conversion-- it heated everything up well in our ~1600sq ft, 2nd + 3rd floor condo (in a 2 unit, 3-story house). We did hear some water hammer and loud roaring of the steam in the pipes and some radiators, but I thought this was 'normal' (before reading Dan's book!). Then about 2 weeks ago, I noticed one air vent hissing a lot and leaking, and so I replaced the air vents on all of my radiators. I then noticed 3 other radiators started leaking from the new air vent holes. They perhaps were 'leaking' earlier, too, but I could not tell because the vents were old/clogged?



I have done the following things one by one, to see if any might solve the problems:



- I went around and made sure all of the air valves were wide open (a couple were part way closed)

-The plumber came back and replaced the 2 main air vents with Vent Rite air vents (#75).

- The plumber also skimmed the boiler a second time (first time was about 2 weeks after the conversion); however, I do notice that our water fill pipe still looks humid in the vacant space above the water-- and I read that it should be bone dry on top? I take it this might indicate that our water is still dirty or oily?

- I then turned the pressuretrol down from 2psi on the main/1.5 psi on the subtractive differential, to instead be 1.5 main/1.0 differential

-I insulated the main steam pipes in the basement (not the returns though)



Despite all of this, the kitchen radiator is still leaking about 1 cup water per heating cycle, and there is a lot of gurgling throughout the heating cycle on this kitchen radiator (I don't hear that much on the others); we also hear water hammer in the pipes below this radiator when the heat is cycling on. The leaking from the air vent starts about an hour after the heat kicks on, once all radiators in the house have gotten warm, and continues until the heat shuts off.



I've included photos of the leaking kitchen radiator, pressuretrol settings, and the boiler and piping. It's hard to capture the pipes in my dark basement, but please let me know if there are any other images that would be helpful. (Note, our neighbors boiler is to the right of ours, so some of their piping may be in the images too.)



Thank you in advance for any help you guys might be able to provide in solving this leak!

Jane_7

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JStar

Boiler

Can you get more pictures from the left side of the boiler, with the return piping?



Any main vents?

BobC

Is it out of level?

It sounds like something is pitched wrong on that radiator or the pipe that feeds it. It's important that everything has a little pitch so water can find it's way back to the boiler. Put a level on the radiator and make sure there is a little pitch towards the input pipe. If it is pitched wrong you can probably shim the vent end up a bit with quarters or a wood shim. Also make sure that radiator valve is fully open.



If the radiator appears to have the correct pitch the problem could be in the pipe under the floor. In that case it might be possible to shim all four legs enough to get everything to drain properly. be careful when trying to lift the radiator so you don't cause any damage to the piping or your back.



Bob

Jane_7

More pics and pitch

Hi JStar- thanks very much for your reply. There are 2 main vents I believe. Here are some pictures of the 2 main vents, the left side of the boiler, and a photo of the water gauge. Do these help?



BobC, thank you very much, too. The radiator is pitched slightly toward to the air valve, and the valve is fully open. I'll see if we can try lifting the entire radiator a tiny bit once the heat is off.

Jane_7

Tried raising the radiator, still leaking

Hi--

I tried raising the radiator up with about 3 quarters under the 2 legs on the right (next to air valve) and 5 quarters under the 2 legs on the left (next to air vent), in the hopes of increasing the pitch of the pipe underneath. Unfortunately, it is still leaking from the air vent; I also still hear the water hammer under this radiator when the system is first getting going, and lots of gurgling throughout the heat cycle.



Do you think the radiator needs to go even higher?



Or, does anyone have any other ideas to fix the leaking air vent? Do you think we need to try skimming the boiler again?



Thanks!

nicholas bonham-carter

Leaking vents

Get a magnetic level and find the slope on all the sections of pipe, from the riser to the wet return. Put masking tape on those points, and Mark them with arrows pointing in the direction of downward pitch. Make sure that from every radiator that the downward flow is back to the wet return.

Those main vents, do not look adequate for removing 90 % of the air from the system at low pressure. I would start with Gorton 2's in those locations (if there is headroom).

Unfortunately, pressuretrols are quite inaccurate at the low pressures where you can save money, and attain comfort, so get a 0-3 psi gauge, and put it neat to the pressuretrol, and see how low it can be set. Sometimes, the linkage inside will disconnect as you adjust it lower, with the result of a higher pressure cutout. A vaporstat can be essential sometimes, especially if the new boiler was over-sized (were the radiators measured by the plumber to size the boiler?)

I wonder if the boiler instructions specify two risers coming up from boiler to header.--NBC

Jane_7

Near boiler piping

Thanks Nicholas- I checked the pipe pitch in basement and they seem to flow to the returns. I also checked the manual and a second riser coming up to the header is optional with my model. I am not sure which size of main vents they put in, but they say Vent Rite [UPDATE: plumber told me they are #75 vent-rites].



I also insulated the basement main lines, but not the returns. Surging and leaking problems persist.



I read Dan's book, We Got Steam Heat, over the weekend and learned a LOT. I checked the near boiler piping against his guidelines and the ones in the manual and found some problems:



1. The close nipple on the Hartford Loop, connecting the equalizer to the loop riser, is not a close nipple or y-fitting, but rather about a foot long. You can see it in the first photo I posted in my 9:20p post from Feb 3.



2. Measured from the TOP of that connecting pipe (the foot long 'close nipple'), it is 28.5 inches from the bottom of the boiler, rather than 26 5/8. The water line is at 28 5/8.

--> Can someone confirm the correct way to measure this dimension for the close nipple height? Is it from bottom of boiler to the bottom, middle, or top of the nipple/connector?



3. Also that foot long 'close nipple' is made out of copper, and from what I've read there should not be any copper, especially in the near boiler piping.



4. I also noticed that the 2 steam wet returns come down on either side of the hartford loop riser (you can see that in the bottom left of the first photo I posted at 9:20p on Feb 3). I am not sure if this is a problem/ if it is still maintaining the proper loop.



I talked to the plumber who installed the boiler today and he is going to come tomorrow to look.



1. Could these issues be causing leaking air vent, water hammer, and sounds of surging/gurgling in pipes?



2. Is it critical for the close nipple to be close or a y-fitting? Plumber claimed it was ok if it's a foot long. He also said this would not be causing our problems. Should I insist he change it to match boiler manual drawing, and be a close nipple or y-fitting?



3. Also, is it important for the plumber to replace copper piping with steel piping in the foot long 'close nipple' pipe in the Hartford loop (connecting equalizer to loop riser)? Plumber said copper is fine, especially in that location because it just contains water. Should I insist it be changed to steel pipe?



4. Can someone confirm the correct way to measure the distance to the close nipple (which should be 26 5/8)? Was I correct to measure this distance from the bottom of the boiler to the TOP of the connector nipple? That's what the diagram in my manual seems to show. But the plumber said this distance should be to the MIDDLE of the pipe/connector.



5. Is it a problem to have the 2 steam wet returns come down on either side of the hartford loop riser? Is it still maintaining the proper loop? Could steam in the equalizer enter the return line in this configuration? Should the loop riser be all the way at one end, with the 2 wet returns next to each other at the other end?



6. Finally, do I need to insulate ALL piping in basement, including the return lines? I've only insulated the mains.



Thanks!

Double D

Some answers

Hartford connection must be a close nipple. On this boiler you need to have 26 5/8” from bottom of boiler to middle or top of Hartford connection to equalizer.

The equalizer should drop straight down with no bends until you’re below the water line of the boiler.

If the boiler has not been skimmed/properly skimmed, it will contribute to your surging water line. Oil and foreign debris may be floating on top of the water. Although I don’t use it, copper is acceptable on wet returns.

It should not make a difference where the returns connect so long as they group below the water line of the boiler.



Contaminated boiler water, high pressure & improper near boiler piping ect. will all cause leaking air vents, water hammer, surging and gurgling.

Close nipple is critical.   [u][color=#0000ff]http://www.masterplumbers.com/plumbviews/2001/hartford.asp[/color][/u]

Jane_7

Near boiler piping

Thanks so much, Double D. It was really helpful to have your feedback. The plumber came by this morning, and is going to re-pipe the hartford loop connector to make the close nipple. We also talked about having a straight pipe for the equalizer until it gets below the water line. I also asked about whether re-cleaning the system might help with the hammer and water surging issues, and he is going to re-skim once again as well. They'll come back later in the week to work on this; I'll update the wall with the results!



Thanks again for everyone's feedback-- I have learned a lot from you all.

Jane_7

Problem solved?

Hi-



I just wanted to update the wall to say that the leaking from the kitchen radiator air vent appears to have stopped!



As I mentioned in my last post, I asked the plumber to straighten the equalizer line so there were no bends until it was below the water line, and put in a close nipple on the Hartford Loop connector (thanks again, DoubleD!). He made those changes, and also replaced that section of copper piping with steel pipe. He then did another skim off the top of the boiler water. He did this yesterday morning, and the heat has been going since-- with no more leaking from the kitchen radiator! I still hear some brier water hammer under radiator, but it has significantly lessened. So, so far so good!



I am attaching a couple photos of the repaired near-boiler piping (the "before photo" is the first photo in my post from Feb 3 at 9:20p). The only thing I notice now is that the Hartford loop connector appears to be about 25" from the bottom of the boiler to the top of the close nipple, rather than 26 5/8"-- but the boiler is raised on a couple of cinder blocks so maybe that is OK? Is this important for the plumber to change, or is it OK as is?

Double D

We'll see who else chimes in

It's nice to see it where the manufacturer suggests but you're better off a little too low than still too high.