banging in steam system - which option of the three to pursue?

nt101

Hello! I am a homeowner and have been plagued by a banging steam system ever since we had a new boiler installed (it was totally fine before). I have approached the installers plus two additional plumbers, and have been provided three different possible solutions. I have no idea which way to proceed, so was wondering if anyone would be willing to provide their opinion.

The new system is a Burnham IN4PVNI-M2, 65,000 BTU. It's a 1,000 square foot apartment on the first floor with four radiators. After installation, water was coming out of two of the air vents on the radiators and it was banging violently. The installer re-piped the water return pipe, making it steeper, and installed an air vent on the return, and that helped a little bit. But it still bangs and clangs a lot, and occasionally spews out water from the air vents. You can hear water sloshing around in the radiators too.

So we have three options:
1. The installer is telling us that all of this is due to the old piping (even though we never had the problem before). He is saying we now need to install (and pay for) a surge tank to catch some of the wet steam.

2. A second plumber has said we should be able to skim the boiler once or twice, and that should solve it. The installer has said they have skimmed it several times, but I cannot find a skim port on the boiler (please let me know if I am wrong). This would be the least expensive solution.

3. A third has suggested we need to completely repipe around the boiler: re-do the steam header, Hartford loop, condensate return, and makeup water line. He said the setup by the installer was totally wrong. This is the most expensive solution.

Based on the info above and photos below, what would you do? And how much do you agree with the other solutions?

Thank you very much in advance for any opinions! This frustrated homeowner would be eternally grateful!

ImYoungxD

Was the boiler skimmed after installing?
How is the water level when it's boiling?

Pressuretroll setting is too high.

nicholas bonham-carter

The supply piping is probably too small, and should not be in copper. Can you measure the circumference, and we can check the requirements.
I don’t see a skim port either, and the water in the sight glass seems to have a layer of muck on top.
Since skimming takes such a long time, if you can get the plumber to put in the port, then you can do it yourself.—NBC

KC_Jones

It's piped in copper which isn't correct, but the basic layout I will call okay, except I can't tell this size. It is supposed to be 2" on that boiler at minimum.

Given what I see I have doubts about the installer skimming the boiler properly or even understanding what that is.

1. no way does the entire system need repiped, again for me this speaks to their lack of knowledge.
2. This would be my guess to start with and yes it's the least expensive route to take.
3. I wouldn't do this yet, but for me the copper would need to go. I doubt you have any luck convincing the installer they should fix the copper so it's up to you which way you want to pursue this one.

I can't see all your piping very well, but there are a couple things that look "weird". In your second picture it's hard to tell what is going where there might be something wrong, or there might not be I can't really tell. Need to understand which pipes go which way.

gfrbrookline

The pictures may be deceiving but the pitch of what you have for a header should to towards the drain side not the supply and it should be black iron not copper.

You get banging in the header because the condensate is trying to drain back into the boiler and is crashing against the steam coming out of the boiler. This will destroy the solder joints in no time.

KC_Jones

Was the boiler always in this location or did you have it moved with the new install?

Jamie Hall

Agree with @gfrbrookline -- though it is hard to tell. Not only the pitch of the header, but the pitch of that unfortunate section of horizontal pipe above it (copper or no, that should have been at a 45 degree slant, not horizontal like that).

Hard to really see the pressuretrol, but if I'm seeing what I think I'm seeing it is way too high. You can do it yourself -- reset it so that the cutout is at 1.7 psi and the cutin at about .7 (1 psi differential).

Do skim it. It needs it.

The comment by the installer (oprtion 1) confirms the near boiler piping -- he hasn't a clue and shouldn't be let back into the house.

I may be mistaken, but the header almost looks as though it is smaller than the riser -- it certainly isn't a size or two larger, which it should be.

It may be that resetting the pressuretrol and checking the slope of the header will cure the problems. I hope so, since -- as you note -- redoing the near boiler piping would be expensive, and I doubt that you could recover that from the installer.

Ironman

Set the Pressuretrol to cut in @ .5 and cut out @ 1.5 psi. It's set way too high now and that may be causing a lot of your problem.

Agree it shouldn't be copper because it won't expand with the boiler, but it appears to be in the right order.

delta T

According to the manual for that boiler, one 2" riser and a 2" header are acceptable. I don't like the copper, would much prefer steel piping, but that's not what is causing the problems.

The skim port on that boiler is located on the right hand side as you are looking at the front, and I do not see it installed, so it is doubtful it was properly skimmed, though they could be removing the relief valve to do it, though that port is so small it would take a very, very long time to properly skim through that port. They should have installed a nipple and cap out of the designated skimming port.

The pressuretrol is actually (surprisingly) set properly (guys if you look close the indicator is at or below 2 PSI, the high limit stop is what you are seeing). Depending on the type of system you have, you may want a different control that can set the pressure even lower than 2 PSI, but that is a fine tuning thing you can do once the other problems are solved. If you can verify the setting on the pressuretrol to be: main (right hand scale) should be at or a little below 2 PSI, and the differential (left hand scale) should be at 1 PSI as a good place to start.

When the boiler is firing, does the water level in the sight glass bounce a lot? (more than 3/4")? If so, this is a good indication that the boiler needs to be skimmed.

I only see one air vent (the little brass bell looking thing on the vertical steel pipe left of the boiler. That is undoubtedly much less venting than you need, and will cause a huge loss of efficiency unless it is replaced with adequate venting.

I think the banging is most likely just from lack of skimming. A proper skim can take hours of just watching a trickle of water flow into a bucket. It is riveting work let me tell you....though with a proper skim port installed we can walk you through it to do it yourself.

To address what the other plumbers and the installer have said:

1. Old piping does not cause wet steam (it was fine before right?) and a surge tank is not something I would expect to see on ANY residential system
2. Spot on, skimming is the answer!
3. While there are some issues with the piping, I wouldn't say you need to re-pipe the boiler. The most worrying thing is the horizontal part of the copper riser. This should be eliminated and repiped at a 45 at least.

EBEBRATT-Ed

Gee, I am usually the one to say it's good enough...let it go. Not this time.

I don't like the two supplies coming off 1 riser from the header. But at only 65,000btu??

Maybe I am looking at this wrong but it looks to me like a steam supply pitched down from the boiler tied in to feed a counter flow supply with a tee coming off....mostly it's side.

How can that not hammer??

If it was me I would turn that old tee straight down put a nipple on that tee into another tee (run) Feed back up off the branch of the second tee to the counter flow main and the bottom of the second tee becomes the return back to the boiler

Ironman

You're right Ed, it sure looks like that one main is a counterflow. It needs to have a drip and be connected separately to the header.

gfrbrookline

@EBEBRATT-Ed, I see a parallel system, one main and a dry return. Note the vent, albeit in the wrong place, on the return in picture 1.

gfrbrookline

I see pic 3 but I am guessing 1 main and a run out attached in a wrong location since it appears to be a smaller diameter pipe. It should come off the main, not the riser and have a dry return.

EBEBRATT-Ed

The way I see it it really doesn't matter which way the steam is going. The newer smaller piping is the drip or return. Water will collect their and cause hammer

KC_Jones

I think the part I circled from your second picture, is what we are all confused by. Can’t tell exactly what’s going on, but it doesn’t look right.

EBEBRATT-Ed

To me I was thinking steam flow left to right. left supply from the boiler pitched down feeding a counter flow main running up hill. Smaller pipe is the return.

gfrbrookline

After looking at @KC_Jones post I have no idea what is going on. Guessing too many people with little knowledge have worked on the system over the years and it is totally screwed up. I would try contact a contractor on here and see what needs to be done.

JUGHNE

If we could see more of that piping from farther back and see what is below it and each side. And where it is in reference to the boiler.

EBEBRATT-Ed

The pic with the crazy T I think that is the boiler flue in the picture