New homeowner with steam boiler

Tolik

I'd like to say a big THANK YOU! to everyone who has helped guide me the last heating season.

It's round two time. Here are the updates.

I finally installed an antler on the end of the long dry return. Used four Gorton #1's on a 10" pipe. This significantly reduced the water hammer sound that was coming form an upstairs radiator. The system also doesn't cycle nearly as often, BUT it hasn't gotten too cold yet to know for sure.

The issue now is that I have water hammer in my dry return pipe. I can hear water sloshing and hammering near the boiler. I know that there should be 28" A dimension but it looks like when the boiler was replaced it was placed on blocks which raised the water line. I'm guessing the old boiler was larger thus the water line now is at about 26" bellow the drop of the dry return.

The dry return also doesn't seem to have much of a pitch to it. It actually looks like its slightly pitched away from the boiler even. The issue is it's sitting on a solid surface. Is it worth for me to try and chisel away some of the wall and try to pitch it towards the boiler a bit? That would lower the A dimension even more by a few centimeters.

Also I noticed that one of the Gorton vents starts to suck air in quicker then the rest when the boiler stops. The others stay hot and closed for more than 30 seconds after the first one is already cool and letting air in. Is this normal? I'll take a video of this and post.

KC_Jones

It's probably sucking air first because it's further away from the heat source. Once the cool they open up and let air back into the system. As far as the pitch that could be the source of the hammering, what about lifting the other end slightly? Did you ever measure your mains to calculate main venting requirements? I just read back through this and didn't notice it anywhere. The venting and boiler size pretty much dictate the pressure. If the boiler is sized even close and you have plenty of main venting the pressure won't build for a long time, if at all. The venting you have there is good for roughly 25' of 2" main.

Tolik

That main runs the length of the house from one corner where the boiler is to the opposite corner where the last radiator is. The length of the house is about 38'.

So I should add two more vents?

I'll try to shim up the opposite end a bit but I'm just worried that will create a sag in the middle.

Tolik

Forgot to attach

KC_Jones

If the pipe was perfectly level it would probably be ok, back pitch is probably causing water hammer. Just as an FYI (if you don't know) the hammer is when steam picks up the water laying in a pipe and "hammers" it into a fitting such as the elbow at the end of that return. I hate to throw this out at you and forgive me if you already addressed this, but do you have any way of putting the vents at the end of the main instead of the dry return? The only reason I say this is with the vents in that position it allows the steam into the dry return to do the hammering. If the vents aren't there any steam that made it that far would probably be at such a low velocity it wouldn't matter. Another option could be re routing the dry return? I had to do this in my home and to me it wasn't a huge deal. I can't see everything you have going on there so I can't say for sure how hard that would be. Perhaps others have some suggestions. There is almost always a way to fix things, just depends how hard the solution may be. As far as venting, it's kind of up to you how far you take it. What I stated is a rule of thumb used around here, but if you are worried about short cycling and possibly wasted fuel you could add more vents. Here is a test. Remove the vents and get to an open pipe. Turn the boiler on and wait until the header gets hot, then start timing. Go to the end of main after last radiator and wait for steam to arrive (feel for heat with your hand) once it arrives stop timing. This is a baseline time. Then basically add vents until you get close to that time, start with what you have then go from there. Make sure each timing is under similar conditions. It's not an exact science, but it gets it done. The longer it takes to get steam through the main the more fuel you are burning to essentially do nothing.

Tolik

Its difficult for me to do anything, all the piping is inside walls other than what i can see in the boiler room. I have no access to the end of the main's.

I'll try the timing trick as you suggested, sounds fun, thank you.

Maybe I'll just leave the vents off and create a sauna in the boiler room

KC_Jones

Tolik said:

Maybe I'll just leave the vents off and create a sauna in the boiler room

Sounds good until all the make up water kills the boiler. On the plus side the high humidity will allow you to set the thermostat lower.
That's tough about the piping. Perhaps someone else has other suggestions? Bueller? Bueller?

Fred

How long is the run of return and does it all sit on that ledge? If it could be pulled off of that ledge at some convenient place, it could be pitched as needed, otherwise, just looking at your level, it looks like you need to cut away an inch or so for a proper pitchover the length of that return. Even if there is a coupling somewhere along that return, before it starts to pitch the wrong direction, you could take the pipe apart at that coupling, put an elbow on to get it off the ledge, another elbow to turn it towards the boiler again and then pitch the pipe towards the boiler.

Tolik

Fred said:

How long is the run of return and does it all sit on that ledge? If it could be pulled off of that ledge at some convenient place, it could be pitched as needed, otherwise, just looking at your level, it looks like you need to cut away an inch or so for a proper pitchover the length of that return. Even if there is a coupling somewhere along that return, before it starts to pitch the wrong direction, you could take the pipe apart at that coupling, put an elbow on to get it off the ledge, another elbow to turn it towards the boiler again and then pitch the pipe towards the boiler.

The run that sits on the ledge is all i can see in the boiler room about 7-8' The rest of the pipe goes inside the wall that is behind a bathroom which is tiled so I can't even cut open a part.

What I'm unclear about is the entire A dimension thing. As I mentioned the "dry" (its full of water as far as i can tell) pipe is about 26" above the water line before it drops down to the "wet" return. If I cut the ledge down about an inch and pitch the pipe would it drain properly? The A dimension will be even lower at about 25" at that point since I'll lower the pipe. Does my question even make sense?

Thank you.

nicholas bonham-carter

Maybe you could drop that pipe to the floor, and make it a wet return. Put a main vent on the drop.--NBC

Jamie Hall

My apologies; I hadn't looked carefully at this thread.

That dry return on the ledge... oops. Aside from wondering how it was done originally -- it surely didn't do that! -- the question is, what to do about it?

Is there, at the low end of it off to the right in your picture, a place where you could somehow fit in a T, with the leg coming towards you and hopefully about 45 degrees down? If there is, the best possible way to handle that, considering your restrictions, would be to do that, and connect the leg of that T to a pipe down to near the floor, then take that over to the boiler and hook it up as a wet return -- which it would be. That could, since it is either a dry return or a wet return, be all copper, and the pipe needn't be that big -- 3/4" even would probably do.

Then on the question of vents. The dry returns must be vented -- otherwise the air coming out of the radiators has no place to go. The steam mains can be vented; if there are no crossover traps, they should be. This will help even out the steam distribution in the building.

Fred

If you don't have any convenient place to uncouple that pipe to put an elbow or Tee on and don't want to open a tiled wall (I wouldn't either), taking a masonary saw or chisel and lowering that ledge, an inch or so, is about the only other option I can see.

Tolik

So...

I tried to take the easier way out and just shimmed the furthest of the "dry" return pipe I could (about 7' out of about 30'.

At the end of the cycle these are the symptoms now. They moved down from the second floor (sleeping is definitely better without banging steam pipes, if any one is wondering.)

Right where the steam/condensate is returning to the "dry" return. Technically at this point its not "dry" since there is water in it. That's the issue. The water hammer starts shortly after and lasts about three min. Nothing too bad so I have time to fix.

Any suggestions?

I'm thinking I need to pitch the "dry" return pipe more. Issue is its behind bathroom wall but after the bathroom I can cut sheetrock.

Fred

Nothing will fix it until you get the entire dry return pitched back towards the boiler. What you have done by shiming that pipe at about seven feet is create a high spot in that run that probably causes a little more water to sit just ahead of that high spot.