Steam boiler is making violent knocking noise

plumber359

About a month ago I installed a steam boiler (do not normally work on steam but did it for one of my regular customers after they insisted that I did it because they did not want anyone else working in house) The boiler was installed almost exactly as the old one, it was pretty much the same boiler just 25 years newer.  The only main difference is that I installed a hydronic zone off of the boiler to heat a small addition.  I took the hydronic zone below water line, have a bypass between feed and return with bronze circulator and no vents on hydronic loop.  The hydronic loop is working quite well, no banging there and when boiler is making steam for rest of house water in hydronic zone does not get above 190 due to bypass.  It is the main existing house that I have banging issues.  I skimmed boiler as instructed in manual upon start up and this process took several hours.  The boiler was in service for a couple of weeks no complaints.  Then a call came in that violent knocking noise had occured.  I returned and skimmed boiler again and two weeks had gone by with no complaints.  Now after two weeks I have complaint of knocking again.  I will go back and skim again but is there anything else I can do?

ChrisJ

Need pictures

Even though it may be almost the same boiler everyone would prefer to see pictures of the piping around the boiler. 

Paul48

Don't

just go back and skim. Find the cause of the problem, or you'll be there every 2 weeks. Is the system over-filled? Where is the knocking coming from? Are there sags in the mains? What are you running for pressure? We need pictures to be able to tell you if there's problems built in to the way it's installed.

plumber359

Pictures of boiler

Here are the pictures

Paul48

Gotta

raise that header up about to just below where the top union is.

ChrisJ

No good

Not sure what size EG series that is, but the header is no good.



You need a MINIMUM (preferably more) of 24" from the water line to the bottom of the header. Please see the URL to pictures in my signature, they are of an EG-45 I installed last fall in my home. You will notice the risers out of the boiler come up 30" + above the water line before dropping down into the dropheader. This keeps water from being pulled out of the boiler. I can't see the equalizer but that should also be 1.5" as a minimum. This is all described in the manual that came with the boiler.



Good news is it will be a somewhat easy fix!





Is that boiler the same size as the previous one?

Dave in QCA

Don't copy old bad work

Agree with the previous posts, header is WAY too low.  Also looks like the pipe size decreases in the horizontal run of the header. That is a big no no, it should only decrease after it has elbowed down.   Get out the manual and make sure that the dimension and orientation of every part of the heater and close boiler piping are all coorect. 



Secondly, I think I see a skim port.  Has the boiler been completely skimmed?  If it is still oily and foaming, that will cause huge problems in the any piping, much more problems when it is combined with erroneous piping.

plumber359

same size boiler, might even be smaller

The old boiler was etither the same size or a little bigger.  It did not have a ratting plate but I think it had either one more section or one more burner tube, cant remember for sure.  The old boiler was hovever similar in height and you can see where I tied into the existing piping.  I came off of new boiler with nipple than reducing elbow and connected with union into existing piping.  I will raise header to make it proper but my question is if old was piped in this manner at same height how come I have issues now and not before?

Dave in QCA

Probably because it's still dirty

I dirty boiler that has not been completely skimmed will make all piping errors behave much worse thatn if the boiler was clean.  But, you do realy want to get this piping corrected too.

ChrisJ

Oil

If you want an easier, faster way to get the boiler clean build a wand as described by Gerry Gill in this thread : http://www.heatinghelp.com/forum-thread/143078/Rinsing-the-boiler





I built one and it was amazing how much disgusting water came out of my boiler after I skimmed it 7 times over a years time.

Paul48

Why?

Don't waste your time trying to figure that out. Make your work correct, and then you can sort out any other problems that might exist. Near-boiler piping is critical. Differences of an inch, plus or minus, can make the whole system not work.Follow the I&O to the letter, when it comes to the near-boiler piping. Keep that header full sized until after it turns down for the equalizer on one end and boiler on the other.Your header being so low, along with the fact you reduced the header, is causing very sloppy steam to be sent to the main.There is only 1 main, running in one direction, correct?

SWEI

Old boiler was etither the same size or a little bigger

I don't suppose anyone did a radiation survey?

Rod

Header Piping is Improperly Configured and Lack Height

Hi - I blew up your picture as much as possible and marked different areas with a letter so others can comment.  The header pipe should be all of one pipe size and at least equal to the piping coming out of the boiler or preferably one pipe size larger. Others have mentioned height above the boiler's waterline. You might also want to take a look at this video: http://www.heatinghelp.com/article/107/Steam-Heating/118/Steam-boiler-near-boiler-piping

- Rod

gerry gill

As the others have stated-

you didn't pipe the boiler correctly which is only going to aggravate the situation. Here is a link to a video i put on you tube of what an oily boiler can sound like. This is a boiler we put in and its piped well, but i have noticed the Peerless boilers like to tell me when its time to clean the water of oil. By the way, it took three visits on obviously different occasions to get the oil out. Now it runs quiet. But you really need to fix that piping.



http://youtu.be/p7U1ktjeQ1U

Paul48

I Hear My Father

" If all else fails, read the directions", and I wish he was still around to say it.

plumber359

thanks

Thanks for all your posts, I can see that I have repipng to do.  The pipe coming out of the boiler is 3"does that mean that my header has to be full 3"?  The main is2.5" so would I want to put a full 3" riser piece coming out of boiler with full 3" elbow and when I get to main put a 3x1.5x 2.5 tee?  I thought that by keeping piping as similar to existing piping as possible I would not have any issues but that is obviously not the case.  The only thing that I changed is the piece coming out of boiler with elbow and connected to existing with union.  I will download paperwork for this boiler and study.  Thanks for all input, the part that I was most nervous about was running hydronic zone off of boiler and that is the part that I have no issues with.  Any reason why after I skimmed boiler it seemed to work for aprox two weeks before banging occured again?

gerry gill

Pipe the header in the size the

manual tells you to, minimum..you can always go bigger..its then full size until after the drop to the equalizer pipe. Otherwise you would build up water in front of the 'ledge' of the reducer fitting..its banging again because more oil has arrived at the boiler.

Paul48

Don't

reduce coming out of the tee. Come out full 3", then reduce with a reducing  elbow to the equalizer.You want to minimize velocity there, because that is what pushes condensate up to the main.Have you checked the main for pitch and sags?