Help - New steam gas boiler making banging sound every 7 days or so

jiajohn

Hi there, I am a home owner in the Boston area and have been haunted by the loud banging sound associated with my steam boiler system for a quite long time. Basically the new cast iron gas boiler was installed in Nov. 2018, and it runs fine without any issue for about 7 days. After that, it generates loud banging sound in the metal pipes every two hours or so when the system starts to burn gas and generate steam for heating, especially in the middle of cold nights. I had to drain and flush out completely all the water (by the way, the water was pretty clean without much rust and dirty) in the boiler, and refill it with the clean tap water. After the water refill, the banging sound goes away immediately and the boiler would run fine again for about 7 days. The metal pipes seem to be pitched properly and all the radiators are fully open and pitched correctly as well. One thing I noticed is that when the banging sound happens, the main vent on the return pipe seems to be bubbly (with water) vs. making normal hissing sound. Can anyone who has knowledge of how to fix this issue help? Regards, John

gfrbrookline

Does this only happen on days when the temperature is in the upper 30's like it has been over the past few days in Boston? I am in Brookline. If so it my just be thermal expansion from the cold pipes and the bubbling may be from the extra condensate associated with the cold pipes.

BobC

Was the boiler skimmed after it was installed? Boilers and pipes are coated with oil to keep them from rusting. Once installed that oil plays havoc with normal boiler operation as the oil changes the boiling action of water. Skimming is different than draining and refilling, when you drain any oil in the water will just coat the inside of the boiler as it drains and then float back on the water as it's refilled.

If you sit and watch the sight glass does the water level move more than + / - 1/4" ? If it does that may mean there is oil in the system and that has to be skimmed off so things can work as they should.

Does the boiler have a skim pipe coming out of a tapping above the boiler water line? If it does there should be a valve or cap that can be removed. You then overfill the boiler a bit so water begins to trickle out. Buy running the boiler just below where it makes steam any oils will start to float out of the skim pipe, adjust the water feed so water trickles out of the skim pipe. The flow of water wants to be very slow, it should take 1/2 hour to fill a 5 gallon pail, I do a couple of pails per skimming session.




Skimming has to be done a number of times to get all the oils out, I had to do my boiler 7 or 8 times to get rid of all the oils in the boiler and piping.

Bob

jiajohn

Thanks for the comments and feedback. I hired a couple of plumbers and I believe one of them put some squick powder into the system to treat the oil issue over the last summer - I am not sure if this has the same effect as the skimming? As for the cold pipe in the basement, since the basement is well insulated and the pipes are pretty warm even in the cold nights. One thing I learned that the BTU (187500) of the boiler is pretty big and there is no hartford loop done for the near boiler piping. I also watch the sight glass today, the water level moves quite a lot (at least two inches up and down) when the steam comes out. I attach a couple of pictures for the boiler system here for you guys to check for more.

jiajohn

I should add that recently one plumber came over to snake the return pipe back to the boiler and got ride of a bunch of dirt on the bottom of the boiler and now the water is running pretty clean from the sight glass. One possibility is that the boiling water could surge via the return pipe and eventually fight with the return steam to make the loud sound when the boiler is running - but this does not explain why the issue only occurs every 7 days or so, any thoughts?

EBEBRATT-Ed

@jiajohn

Watch the water level when the boiler is steaming. The water level shouldn't move more than a total + or- 3/4" If it does the boiler probably needs skimming. Draining and refilling will probably not help as the contaminents are floating on the surface of the water.

Unfortunately the installers did not follow the boiler MFG recomended piping. Dig out the boiler manual and look at it

KC_Jones

My guess is surging due to not being skimmed. IMHO Squick is not a replacement for skimming, and I think you are experiencing this.

The problem is being amplified by the incorrect boiler piping. That's a colliding header and all they are good for is reducing efficiency and sucking water out and into the system. Not good and you are feeling the effects of that.

Are manuals really that hard to follow? I mean shouldn't this be on the license test? Here is a manual read and and let's see if you can do what it says.

KC_Jones

I just noticed they reduced the outlet at the boiler, if memory serves that is a strict no no on those boilers. So in addition to the piping being run improperly, it's the wrong size.

That's a do over.

dopey27177

Banging issue.

It looks like the dry return is piped into the equalizer.
If this is so, what happens is steam flows into the dry return and
collides with the returning condensate and that causes banging.

The boiler header should have increased one size to allow condensate to drain to the boiler at a level lower than the "T" that feeds steam to the building.

The pressure control appears to be not level.

No Hartford loop this dangerous to some degree.

The way the boiler install was done voids the manufacturers warentee.

See Attachment.

This is what a boiler install should look like.


Jake

JUGHNE

Are all the pipes sloped such that they drain back to the boiler?

What looks to be a dry return appears to be higher than the steam main.

Does the piping make a loop at the far end of the basement....to the right of the boiler?

jiajohn

Thank you guys for the insightful discussions and tips. I am a home owner and inherited this system from the previous owner. I check the install manual and agree that the near boiler piping is not done right as a hartford loop was recommended, etc. But can someone enlighten me why it runs fine for several days if oil is inside the system to cause surging and wrong piping might be the root cause, isn't the banging sound always present? Also does the boiler have any access for skimming?

Hap_Hazzard

It might only be noticeable on cold days because the cycles are longer. Do you see any correlation between noise and outside temperature?

vaporvac

What pipes are banging. I had this with my old boiler and discovered it was due to mis-pitched piping. When drained it would be fine for a while until that pipe collected enough condensate to be a problem. Then it would start all over again. However, I would definitely find a way to skim that boiler as it can take quite a while to get all the oils out of the system reducing efficiency until they're gone.

jiajohn

When it makes banging sound, the sound seems to follow the steam traveling after the system starts initially and it becomes quite after few minutes. Since the whole pipe is made of black steel metal, it is really hard to tell where it originates. Yes it does make a loop at the far end of the basement (I am a rookie but I think it is an one-pipe system).

Does anyone here service the greater Boston area as I would like to see if the boiler can be skimmed?

JUGHNE

I would suggest to get the owner's steam primer "We Got Steam Heat!". Available above here.

dopey27177

Again: Look at where the dry return connects to the boiler equalizer.

Steam from the boiler header enters the dry return. If condensate builds up in the dry return you will get banging.

I can see why the banging is intermitent, The boiler has to run a
long time before a lot of condensate begins to collect in the dry return, when that happens banging occurs.

Try this to locate the banging, from a cold start when steam begins to flow touch the dry return near the boiler Then go to the end of the steam main and touch the dry return.

If the dry return is hotter near the boiler that is where your problem is.

Additionally, when all the work is completed insulate the rest of the steam piping in the basement. You can leave the dry return uninsulated.


Jake

Fred

Very hard to see from your pictures but it almost looks like this is a counterflow system. Are the mains lowest at the boiler and rise from their? If so, it is Counterflow and those mains should each have a drip at the boiler that drops to below the boiler water line.
If it was originally a parallel flow and the returns are at the end of the mains, then the installer may have pulled the mains down at the boiler to connect to the header. It will hammer.
Check what @dopey27177 says about the pipe that connects to the top of the equalizer. Is that suppose to be a return (at the end of one of the mains) or is it suppose to be a Main? In any case, it is piped wrong (more wrong if it is a return) In either case, it is a problem.
Finally regardless of the pitch of the mains, check to see if any of them have a sag somewhere along the main that will hold water. If so, they will bang when steam hits the water that has pooled in that sag.
The only other question I'd ask, before we can advise how to fix the problem, is : Are you doing anything differently every 7 days that might cause the boiler to run differently or longer (like a 7 day set-back on your thermostat). It is unusual that the banging only happens every seven days.

neilc

is that pressuretrol set all the way up ?
what are you running at ?
pressure is not your friend.

jiajohn

@dopey27177 @Fred Thanks for the feedback. Sorry I am a layman on steam and don't quite understand the terms such as dry return, mains, counterflow, parallel flow, etc. Let me try to describe it as it is kinda of hard to tell from pictures. The metal pipe that connects the boiler's steam output is lower so that the steam can go up easier, then it starts to pitch higher because it has side branches connected to the radiators in the upstair rooms, eventually it reaches the highest point, where it intersects 90 degrees with a smaller metal pipe which is pitched lower towards the boiler to form a basic close loop (like a rectangle with three sides carrying steam and condensed water, and one side returning back to the boiler (where the white bail is located in the picture above)). The pipe that connects the top of equalizer sends steam up to the last radiator in the room and I guess it does carry condensed water back as well. I can try to get some more pictures. Lastly I didn't do anything differently every 7 days or so, except for the outdoor temperature variations.

jiajohn

@neilc The pressure tolerance level is pretty much all the way up about 8PSI and the actual pressure reading gauge is dead

gfrbrookline

@jiajohn , I live in Brookline and I use @New England SteamWorks . There is no one better in the area for steam than Ryan, (401) 954-3510, https://www.newenglandsteamworks.com/contact-us

gfrbrookline

Turn the outside adjustment of your pressuretrol down to .5 and the white dial inside to 1. Doing this will let you system run within what is considered a normal range for steam heat and may quiet things down a little.

nicholas bonham-carter

Your supply, near boiler piping is not correct, and will throw lots of water up into the mains. The risers from the boiler, and the horizontal header may be smaller than the manufacturer’s specifications. The order of connections should be:
1. Left riser, full size, with swing joint into header.
2. Right riser, full size, with swing joint into header.
3. Then any takeoffs to the mains.
4. Equalizer at the end of the header.
5. A skim port should have been installed, for boiler cleaning, and this could be a tee on one of the outlets on one of the risers.
Download the installation instructions from the factory, and study the diagram, and compare the required pipe sizes with what you have, which is close, but no cigar!
I can’t see what you have in the way of main vents, but you need them to balance the system.—NBC

ethicalpaul

jiajohn said:

@neilc The pressure tolerance level is pretty much all the way up about 8PSI and the actual pressure reading gauge is dead

Wow. How did it get up there?

KC_Jones

ethicalpaul said:

jiajohn said:

@neilc The pressure tolerance level is pretty much all the way up about 8PSI and the actual pressure reading gauge is dead

Wow. How did it get up there?

Installer probably put it on how it's shipped and didn't give it a second thought.

ethicalpaul

that's a good possible answer. I can verify that my Peerless shipped with the pressuretroll at 8psi but I wanted to hear it from the HO

dopey27177

see attachment:

PICTURE THREE OF BOILER PIPING

Problem at "T"

Excuse the hand writing, have arthritis in my hands

dopey27177

Boiler pressure:

Set the pressure control to 2 psi cut out 1 psi cut in'

Make sure the pressure control is level

Jake

JUGHNE

The metal pipe that connects the boiler's steam output is lower so that the steam can go up easier,
Did the installer tell you that....steam can go up easier?

then it starts to pitch higher because it has side branches connected to the radiators
So at the boiler is the lowest part of the horizontal steam main pipe??

the highest point, where it intersects 90 degrees with a smaller metal pipe which is pitched lower towards the boiler to form a basic close loop
So the low point of the steam main is at the boiler and goes uphill to the small pipe that returns to the boiler?

You can verify this simply by measuring from the bottom of the floor joists (small wood beams that are about 16" apart) to the center of the pipes. (floor joists are assumed to be fairly level).

About how far is it from the boiler to the first pipe that feeds a radiator?

JUGHNE

Could you add more pictures for the side of the boiler that does not have the controls on it. You have 2 pipes dropping down connected to the pipe that goes into the bottom of the boiler, can you show us where those two are connected near the ceiling and what they are connected to and where they head?

jiajohn

Guys, thanks a lot for the comments. I am adding more pictures here. I also made a rough drawing of the system piping to give you the overview. I tried to lower the pressure setting in the past but one of the rooms was not getting heat so I have to put it to the original setting. The installer is gone and I could not find the contact number from the remaining paperwork/manual. I also took a pic of the water in the sight glass and can see small yellow residue on top of the water - not sure if it is rust or oil.

jiajohn

jiajohn

Jamie Hall

Step 1. Put the pressure back down -- that outside pointer no more than 1, better a bit below that.

The high pressure will ruin what vents you have, if it hasn't already done so.

Call @New England SteamWorks and get them over there to fix things. There is so much wrong with that piping -- overall -- that I wouldn't even know where to begin on the fixes. Other than the obvious one of that one radiator that is piped off the equalizer... which I simply can't believe was done.

You are going to need to add main venting. You are going to need to completely repipe the boiler. You are going to need to add some condensate drips. There's nothing there that can't be fixed -- but there's very little in the basement that doesn't need to be fixed.

Fred

@jiajohn , That is oil on the top of the water. The boiler needs a good skim (or a few).
If I were you I would go to the "Find a Contractor" tab at the top of the page and find someone who knows steam and can put some eyes on your system. If @New England SteamWorks or @Charlie from wmass or @EBEBRATT-Ed cover your area, they are all excellent Steam Pros.
It is just too hard for us to tell from your pictures what may be the core cause(s) of your problem. From my perspective, it looks like the system may be a counter-flow (lowest point of the main(s) at the boiler which should mean that there are drips that drop to the wet returns, but those mains could pitch differently elsewhere in the basement that turns them into parallel flow. In any case, we simply can not see what is happening with the full length of the Mains.

JUGHNE

I think that the installer dropped the main by swinging it down with the old existing 90 on the steam main that looks to be about 10-12' away. That may explain "the pipe being short so it is easier for the steam to travel" .

The high point of the main is where it is reduced at the dry return.

That may be why it looks to be a counter flow main.
I think if that was raised up to make it a parallel flow and then the upstairs radiator connected as another main on the header that would be a good start.
Then fix the equalizer/HL with venting.

Definitely need a pipe fitter to straighten this out.
Don't call the original installer, he was pretty lost on steam systems. IMO

jiajohn

Thanks a lot for the comments and feedback. It seems that I need to hire a pro to redo a lot of piping work which I assume is pretty labor intensive and expensive. I am a layman on this but how do I know this is going to solve the issue as we still don't know the root cause yet? If piping is the issue, I should experience the banging sound every night, not every 7 days or so. For example, I have not been able to duplicate the issue for the past several cold nights after the drain/refill over the weekend. Has anyone seen and solved this kind of issue before?

Fred

@jiajohn , I have to repeat: If I were you I would go to the "Find a Contractor" tab at the top of the page and find someone who knows steam and can put some eyes on your system. If @New England SteamWorks or @Charlie from wmass or @EBEBRATT-Ed cover your area, they are all excellent Steam Pros.
It is just too hard for us to tell from your pictures what may be the core cause(s) of your problem. From my perspective, it looks like the system may be a counter-flow (lowest point of the main(s) at the boiler which should mean that there are drips that drop to the wet returns, but those mains could pitch differently elsewhere in the basement that turns them into parallel flow. In any case, we simply can not see what is happening with the full length of the Mains.

You don't have to pay to repipe, unless the Pro says that's your problem.

Jamie Hall

The reason several of us are suggesting to get a pro in there -- Ryan from @New England SteamWorks , or Charles ( @Charlie from wmass ) or @EBEBRATT-Ed is not necessarily to redo pipework. Nor is it to spend your money. It is to get eyes on to the system. All we have is some photographs and verbal description; while sometimes that is enough to diagnose a problem remotely, sometimes it isn't. This is one of those times when it isn't.

mattmia2

Is the water line in the boiler the same height when it is cold before and after you drain and refill? If it is making wet steam it could be bringing enough water up in to the system that it triggers the feeder and raises the water line over a number of long cycles which eventually raises the water line to a point where it brings enough water in to the system to cause water hammer.