counterflow steam problems

Uman

I recently replaced an old oil-fired steam boiler (i don't remember the size of it). I replaced it with a Weil McLain natural gas PEG-40. I had previously figured out the total square ft of steam of the radiators using an old manual (Gurney) found online, seeing how all but two of the radiators were Gurney radiators. I came up with 302 sq ft of steam and the PEG-40 covered a little more than that (the next size down was too small). Long story short, there was a lot of banging in 3 -4 of the radiators whereas with the previously boiler there wasn't any. At the advisement of the factory rep, I re-piped the header using larger pipe (3") than I originally used and piped it according to the diagram shown in the manual for counter flow systems which is what the house has. Here is some other information. There are two 2" steam mains, one going in one direction and the other in the opposite direction. There never were any end of the main vents installed (and I'm not going to install one due to asbestos all over the piping) so all of the venting of the system happens through the individual vents at each radiator. The mains seem to be pitched back to the boiler. I went around and put shims under any and all radiators that were not pitched properly. I made sure that all valves at the radiators were open all the way. I even installed new adjustable radiator air vents on each radiator. The pressure of the boiler is set at 1/2 psi. Homeowner is saying that it still bangs just not as much as before. I know that banging is a result of steam hitting water but cant seem to stop it. Not sure what else to do. I am about to go crazy.....HELP!

KC_Jones

Have you skimmed the boiler? Sounds like you could have wet steam getting into the mains causing the banging, especially since you say it didn't bang before. Some pictures of the piping would help also.

JUGHNE

We assume this is a one pipe system. Although I just looked at a 2 pipe counterflow with rad traps. The system I looked at has a concentric 2 X 2 1/2" reducing bushing which hammers on start up. Very minor though. Pictures of your NBP would help a lot.

Fred

Have you heard the banging? Can you tell the approximate location(s) of the banging? Have you checked to make sure none of the mains have a sag? I assume the drips drop down to a wet return somewhere near the boiler and that wet return is still below the boiler water line? Did you install a Hartford loop and is it tied into the equalizer a couple inches below the water line?

Uman

KC Jones, I did not skim the boiler but probably should go back and do so. Why does that make such a huge difference?
Fred, I initially heard the banging. It is not at the boiler but rather at 2 -3 of the further-est radiators (one on the 2nd floor and 2 on the first floor). The second floor radiator piping is almost all vertical (1"). Most of the mains in the basement are enclosed in a soffit that was really hard to look into. What I could see looked like it was pitched back to the boiler. The two 2" steam mains are what the condensate travels back to the boiler. There are no separate condensate returns. Right before the two mains get to the boiler, there is a 1" copper pipe coming off the bottom of the main that brings the return to the boiler. I did install a hartford loop and it is tied into the equalizer line. Did it all by the manuals instructions. I will try to get some pictures downloaded tomorrow for you to look at.

Fred

Those 1" copper pipes are the "Drips" for each Main. Did you install those or were they installed from the previous boiler? How do the come together and tie into the boiler? It is possible that they could be clogged down towards the floor and letting water back into the mains, causing some banging towards the end of a heating cycle and then when the boiler is idle, enough water slowly drains back to the boiler to let it start the next cycle fairly quietly. Pictures would be helpful. Even though the mains are pitched, A sag in the main, hidden in the soffits could also be the culprit.

ChrisJ

Please post pictures of the boiler and piping around the boiler.

Also include pictures of the radiators if possible.

KC_Jones

Without the skimming you could and most likely are surging from the oils on the surface of the water. This will suck excess water into the mains and can cause banging.

Dennis1679

Skimming has solved many surging problems for me. If it's piped right for counterflow. The boiler steam feed should go above the steam main, turn down and connect to the boiler return (equalizer line), the steam main connecting to the boiler steam feed on it's way down to the equalizer.
If all that is done right, clean the boiler!

Fred

Dennis1679 said:

Skimming has solved many surging problems for me. If it's piped right for counterflow. The boiler steam feed should go above the steam main, turn down and connect to the boiler return (equalizer line), the steam main connecting to the boiler steam feed on it's way down to the equalizer.
If all that is done right, clean the boiler!

I don't think so. The risers, Header, equalizer for a counter flow is the same as it is for a parallel flow. Risers out of the boiler should tie into the header, not rise above the mains and turn down. Equalizer should tie into the end of the Header, after any mains.

Eric_32

Fred said:

Dennis1679 said:

Skimming has solved many surging problems for me. If it's piped right for counterflow. The boiler steam feed should go above the steam main, turn down and connect to the boiler return (equalizer line), the steam main connecting to the boiler steam feed on it's way down to the equalizer.
If all that is done right, clean the boiler!

I don't think so. The risers, Header, equalizer for a counter flow is the same as it is for a parallel flow. Risers out of the boiler should tie into the header, not rise above the mains and turn down. Equalizer should tie into the end of the Header, after any mains.

It sounds like he's referring to a dropped header..

You must skim the boiler, and it will take hours to do it right. New boilers are full of oil as well as the new piping with cutting oil.

nicholas bonham-carter

Look in this "steam survey" from Peerless, and on page 2 it shows the correct piping for a counterflow system. This will prevent condensate from dripping down the risers directly into the boiler.--NBC

http://www.peerlessboilers.com/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=140&PortalId=0&DownloadMethod=attachment

Fred

Thanks @nicholas bonham-carter the ones I've seen have been plumbed like a Parallel flow except with drip legs on the mains that drop to a wet return, near the boiler.

DanHolohan

Good link, N.B.C. Thanks. It has to be that way to work.

nicholas bonham-carter

Good on Peerless-a quality company unlike some others we have heard about!--NBC

Dennis1679

That's what Ipoorly described. I've done quite a few of these and it works well

SolarGuy1

Th

nicholas bonham-carter said:

Look in this "steam survey" from Peerless, and on page 2 it shows the correct piping for a counterflow system. This will prevent condensate from dripping down the risers directly into the boiler.--NBC

http://www.peerlessboilers.com/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=140&PortalId=0&DownloadMethod=attachment

I was looking for info on drip line piping and ran across this discussion but the link is no longer valid. I there another diagram or photo? I believe my drip lines are incorrect as they are tied into the wet return of the boiler, not the Hartford loop.

nicholas bonham-carter

Try this

https://www.peerlessboilers.com/wp-content/uploads/2018/01/OnePipeSteam.pdf