One pipe steam system

marde239

I have a one pipe steam system. The line with my bathrooms have a lot of knocking and banging. Last year water was pouring out of a failed varivalve air vent in my upstairs bathroom. Is there a " flush type valve" that I can install on pipe returning to the boiler? Also the pipes returning to the boiler have these " square type plugs" on them. Should there be main air vents there?

Fred

Check to make sure those radiators have a slight pitch back to the steam supply pipe. If the banging is under the floor, raise the radiator a bit with shims and then repitch it back to the supply. Tjhje goal is to have some pitch in the radiator and any horizontal piping so that water flows back to the boiler.
Also make sure your Pressure is set properly and that the Pressuretrol is set for a Cut-in (scale on front of the Pressuretrol to .5PSI and the white wheel inside the Pressuretrol is set to "1" (facing out front). Make sure the Pigtail (looped pipe under the Pressuretrol) is clean and not plugged with gunk.
Do you have any vents on the Mains/dry returns? You need to vent the Mains, otherwise you are wasting fuel trying to push air out of the Mains, through the radiator vents, a lot of air.
Does the boiler water in the sight glass bounce a lot (more that .5 to 1 inch)? If so, you probably need to clean and skim the boiler. All of these things will affect the boiler operation in the ways you are seeing.

STEAM DOCTOR

Ditto to what @fred said. You are trying to flush the returns. Might be a good idea but not necessary the cause of the banging

Jamie Hall

And a third second, or something. The very first thing to do is to check the pitch on any horizontal pipes leading to those radiators. They shouldn't be horizontal -- they should slope back towards the main at at least 1 inch for 10 feet, and more won't hurt a bit.

Also check the pitch of the radiators, as @Fred said.

There's no need to "flush" anything on a one pipe system, if the pipes are pitched correctly. If they aren't there's no point to doing it anyway.

marde239

Thanks for the input. Where should the main vents be located? I can seem to find them. I included a photo of something that I think should be a main vent.

hboogz

Jamie Hall said:

There's no need to "flush" anything on a one pipe system, if the pipes are pitched correctly. If they aren't there's no point to doing it anyway.

Hey @Jamie Hall , Could you expand on that last point ? If pipes are pitched incorrectly in one-pipe flushing won't do much since water will remain in the pipes anyway?

Jamie Hall

hboogz said:

Jamie Hall said:

There's no need to "flush" anything on a one pipe system, if the pipes are pitched correctly. If they aren't there's no point to doing it anyway.

Hey @Jamie Hall , Could you expand on that last point ? If pipes are pitched incorrectly in one-pipe flushing won't do much since water will remain in the pipes anyway?

Not only stay in the pipes, but bang like crazy. Fix the pipe pitch first.

marde239

Is it possible my one pipe steam system was installed without steam mains?

Fred

marde239 said:

Is it possible my one pipe steam system was installed without steam mains?

Almost anything is possible. Post a picture of what the piping looks like around the boiler and where the pipes run out to radiators.

Abracadabra

marde239 said:

Is it possible my one pipe steam system was installed without steam mains?

Not likely.

hboogz

@marde239 where was the picture you posted taken from? The end of the steam main ? Can you post a picture further back with some perspective ?

Not a pro, but normally at the end of a one-pipe steam main an elbow is usually used for the gravity return. That looks like a Tee with a plug and then copper sweated on. Perhaps a repair job done years ago.

mmc239

The picture I posted is behind a wall so I can't get any further back. It is the end of the line before it goes back to the boiler. I have added some additional photos that are accessible to take a picture.

Fred

Looks like Mains with a couple drip legs at the end of them. Main vents can go at the ends of those mains if you can get those plugs out and add an elbow and nipple to mount the vents to. I'm not sure who we are talking to though @marde239 or @mmc239 or if you are one and the same?

mmc239

What is the benefit of adding vents? Will it quiet my system, radiators etc?

Fred

It will save energy/fuel costs and help reduce pressure. All the air in the mains will have to be vented out through the radiator vents if there are no main vents. That takes a lot longer than it would with good main venting. The added time it takes to push the air out through those small radiator vents is using fuel to make the steam that pushes the air out. That also increases the system pressure and all that happens before you even get to the point where the steam can do what you want it to do, heat those radiators.

LionA29

You might be overwhelmed with all the troubles and headaches entailing your system. Try and get a pro to look at it and give you some direction and possibly get a service done. Good luck.

hboogz

Tons of benefits and a must. What are you struggling with? Have you purchased any of dans books?

hboogz

Also looks like they reduced that copper to 1". Maybe be an undersized return based on the size of the connected EDR

Fred

Size wise I think it's OK (if it is 1"). Looks like it may be smaller? which could easily clog. I'm looking at the first picture posted earlier in the thread. Second set of pictures look ok. Not crazy about those two Mains tee'd together above the boiler header but at least that is not a Bull headed Tee. It is what it is.