Fixing the gurgling at the end of my Steam Mains

trivetman · November 16

I've made a lot of improvements to my steam heating since moving into this house 8 years ago. Couldn't have done any of it without this wall….so THANKS!!!! Hopefully this is the last thing that needs to be looked at…for a while anyways.

It's two pipe steam. Vapor type system. I had a new boiler (SteamMax) put in two years ago as the old one was leaking. The system doesn't build pressure since the new boiler went in. I've had it go for long runs (45+ min) without the pressure going over a few ounces. All the radiators get heat. I have a vaporstat set to 10 oz cutout but I don't think it ever trips with the exception of when I've needed to skim it after the install.

The only problem is that I get a lot of gurgling, bubbling sounds at the far end of the house from the boiler. It happens on a cold start and goes away within a few minutes of the radiators getting hot. I hear it in both the basement as well as from the radiators on first and second floors. It's something I can live with but if I can fix it I will. Other radiators in the house are pretty quiet. Not totally silent, but quiet.

Two section of mains come from the boiler. These each run one side of the perimeter of the basement and meet up again at the other end of the house. The picture below shows where they meet up, transition to copper and drop to the ground (it's hard to see the copper line drop in the picture. It goes straight down after the 45). The two lines drop independently, join well below the water line and the wet return runs back to the boiler. The mains are long (one goes 60 feet. The other 90 feet) and run flat along with basement ceiling without any pitch.

I had someone from the company which put in the boiler come look at the situation. He ID'd the reduction circled in red as trapping water. The noises are coming from radiators which are fed just prior to this spot so it makes perfect sense (and it's something you guys already helped me learn about on previous posts). He did not think that the other main had the same 'trapping water' issue, though there are similar reductions in the piping (circled green). There is an additional reducing bushing on this line a bit further back outside of the picture. This area of piping leading to the green circle has some pitch to it and radiators on this line do not seem to be making noise, so maybe it should be left alone.

The pro who was here today recommended something in addition to correcting the reducing bushing. This is really where I need your help. He wants to put 'bucket traps' on both drops to the wet returns - around the positions I put the blue squares. I am guessing a bit as to where exactly he wants to put them but definitely on the vertical drop above the waterline. He thinks the steam is 'getting down into the return' and 'messing with the waterline' if I understood him correctly. Bucket traps are new to me….so help me out. Thoughts?

109A_5 · November 16

Hello trivetman,

This makes no sense " I have a vaporstat set to 10 oz cutout but I don't think it ever trips with the exception of when I've needed to skim it after the install. " why are you building any pressure when skimming ?

I'd get the mains to drain correctly first and correct any other pitch issues as best as possible.

trivetman · November 16

https://forum.heatinghelp.com/discussion/comment/1820545#Comment_1820545

@109A_5 - thanks for the feedback. After the boiler was first installed and skimmed, the vaporstat started cutting out after only a few minutes of steaming. After skimming again, the pressure buildup stopped happening. I went through a number cycles of this happening over the first few months of operation. After 4 or 5 skims the system was cleaned up and I don’t think the vstat has cut out since.

I won’t say I fully understand why the pressure built so quickly early on but it did.

Anyways, what I am really after is info on these bucket traps my guy wants to put on. Sounds like you don’t think its the right move, at least not now.

The arrow you put asking about a size change…..There is not a size change there. However, there is a size change on that main 6 to 8 feet prior to your arrow (outside of the picture). But the noises I am hearing are not coming from that main. The noise is definitely from the main with the ‘red circle’

109A_5 · November 16

OK so the pressure build up was not during actual skimming event. During steaming there was probably some surging going on due to the manufacturing oils.

trivetman · November 16

https://forum.heatinghelp.com/discussion/comment/1820548#Comment_1820548

yes exactly

109A_5 · November 16

What does the Pro think the bucket traps are going to fix ? Presently I don't see any benefit.

trivetman · November 16

That’s kinda why I am on the wall asking. He thought the steam was going down ‘towards the waterline’ and stirring things up. He wanted to prevent the steam from going down towards the wet return.

Im having a hard time seeing what the traps would do as well.

Steamhead · November 16

@trivetman , if those drips go to a wet return, the traps are not needed. The standing water in the wet return will keep steam from entering the drips. Traps there might cause banging, because they change the "A" dimension to a "B" dimension which will cause water to back up.

109A_5 · November 16

" The only problem is that I get a lot of gurgling, bubbling sounds at the far end of the house from the boiler. It happens on a cold start and goes away within a few minutes of the radiators getting hot. "

From a cold start, if there is some trapped water in various parts of the system the moving air trying to get out of the system through the vents may bubble through and/or push the puddled water around and along. Once the main vents close that flow is dramatically diminished and is mostly just condensate flow (not much sound).

The majority of the steam then goes to the radiators and condenses, the condensate then fills up the low points again and waits for the next cycle. Correct the poor piping techniques (lack of an Eccentric Reducer or other appropriate technique) and add pitch if possible.

You said it is a two pipe system, the condensate end of each radiators drops down to the wet return ?

trivetman · November 16

@109A_5 - yes it is two pipe. The returns from radiators feeds into dry returns which ties back to the boiler at the hartford loop. They do not meet with the wet returns at the far end of the basement in the picture.

@Steamhead - thanks. I am trying to sort out if putting these traps on is a ‘might help and won’t hurt’ move, or if its a ‘might cause more problems’ move. Your comments make me think its the latter, which I had been afraid of.

I might have to do this myself next spring after the cold. Trying to convince a pro to fix it ‘my way’ often doesn’t go well…..

DavidK_2 · November 16

I like a little hisssing and gurgling. It lets me know the house is alive.

trivetman · November 16

https://forum.heatinghelp.com/discussion/comment/1820633#Comment_1820633

Always looking on the bright side….

Jamie Hall · November 16

If those drips go below the water line, traps on those lines are a "won't help and WILL hurt: item. Don't do it. Don't let anyone else do it.

The gurgling you hear is, as has been said, almost certainly condensate trapped in low areas on the piping. The guys have pointed out some locations which are suspect.

trivetman · November 17

If I do this myself, I think it seems easier to do using eccentric couplings rather than run 2" iron the whole way until turning vertical.

Is there an online retail place which is good to get the eccentric couplings? They don't seem to be at supplyhouse which is my usual go-to.

delcrossv · November 17

Zoro and Ferguson have them. Kinda pricy.

Google Anvil eccentric reducer.

109A_5 · November 17

I would just cut the copper remove the present iron reducing bushings put in a 2" nipple and a reducing ell pointing down then rework the copper a few inches lower so it drains correctly. You may want to extend the 2" a bit so the vents are not so close to the end. I would replace the horizontal copper in the picture with a 2" nipple.

Fixing the gurgling at the end of my Steam Mains

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