Eccentric reducing bushings for steam radiators?

Abracadabra

Has anyone seen the use of eccentric reducing bushings for steam radiators? Just about every radiator I've seen is threaded for 2" and then is bushed down to whatever (1-1/2", 1-1/4", 1") using a regular bushing. This traps water in the radiator.

I have a customer that's complaining about water hammer on one specific radiator. It's pitched correctly, runout is pitched correctly, no water being trapped in pipes. Upon disconnecting radiator, about 4-5 ounces of water are found inside. The only thing I can think of is to use an eccentric bushing to reduce the amount of water being trapped in the radiator.

She's taken a video of the hammering, there's 3-4 hammers when steam starts to enter radiator and then it's done.

Jamie Hall

I don't see why you couldn't do it -- but I also would be rather surprised if it fixed the problem. After all, if that were a common situation, it would be just that -- common, and it isn't. There are hundreds if not thousands of systems piped with regular bushings!

For one thing, the velocity of the steam drops so fast when it enters the radiator, that while one could get a nice gurgle (and sometimes do!) it would be a little surprising if one could get enough velocity to get a hammer.

Double check all the piping -- not that I doubt you, but sometimes a little six inch piece can sneak in unnoticed and cause a lot of trouble.

Abracadabra

Jamie Hall said:

Double check all the piping -- not that I doubt you, but sometimes a little six inch piece can sneak in unnoticed and cause a lot of trouble.

Yeah... I'm stumped on this one. Spent too much time already trying to figure this out. Never happens when I'm there... sort of like when you take your car to the mechanic.. But she's got the video with sounds of it happening in the middle of the night. I've even thought that she's purposely banging on the radiator herself with a hammer.... dunno..

EBEBRATT-Ed

How large is the radiator? Maybe vent it a little slower. eccentric bushing
or coupling or turn down with a reducing 90

ChrisJ

You sure it's not expansion noises?

Abracadabra

EBEBRATT-Ed said:

How large is the radiator? Maybe vent it a little slower. eccentric bushing
or coupling or turn down with a reducing 90

It's an 3 col, 38" 8 section 40edr, vented with a mom#4.
She says that the hammering has definitely reduced with the new vent, but it still hammers.

Some videos she emailed to prove the hammering, which of course never happens when I'm there.

hammering starts at :50 in, expansion noises before and after


hammering on this one starts at about 1:00 in for about 1 min, then starts up again at around 2:55

Fred

Is it possible this is after a set back or after she has just turned the heat back on after having it shut down for a while or after she has shut the valve to this radiator off for a while and just opened it again and that radiator/any water sitting in the bottom has gotten really cool/cold? It sounds more like expansion of or between the sections than actual hammer.

Paul48

Hmmm.....Can't see the vent. Maybe the angle.

Mark Eatherton

Steam collapse? Vapor gets over standing puddle of condensate and collapses in on itself, causing banging? Just the radiator expansion would be enough to wake me up. Maybe try a TRV on that radiator. Grasping here...

ME

ChrisJ

All of my radiators hold water, as you said they're bushed down.

You may have mentioned it, but what pressure is the boiler running and what vents are on these radiators?

Also, what valves are on them? I seem to recall some people having issues with smaller valves that don't allow the steam to pass the water very well.


Is there any chance the hammering is actually taking place in the runout below the floor?

JUGHNE

Yes, I have been told there is a difference between hot water valves and steam valves. The steam valves are "fatter" and have more room for the condensate to flow past incoming steam.
Hard to tell unless they are side by side.

Abracadabra

1-1/2" steam valve. one of the first things i checked.
vent is a MOM#4 boiler is running at max pressure of 14oz. vaporstat controls 2-stage valve on a WM lgb-13 keeps pressure between 6oz-14oz.
the dark video is early morning. yes, there's a couple degree setback. It's not huge, I don't remember the exact details of the setback they have set offhand. the daytime one i think is midday.

Mark Eatherton said:

Steam collapse? Vapor gets over standing puddle of condensate and collapses in on itself, causing banging? Just the radiator expansion would be enough to wake me up. Maybe try a TRV on that radiator. Grasping here...

ME

I'm grasping too @Mark Eatherton I'm kind of stumped. Got the radiator extremely well pitched, in both front/back and left/right to minimize any condensate sitting in the bottom of the radiator.
I've considered swapping out the radiator with a completely different type just to see if we get anything different. Also as a test, I've even thought about piping the whole thing in 2" down to the stub out of the floor. I'd have to turn the radiator in the other direction though.

Paul48 said:

Hmmm.....Can't see the vent. Maybe the angle.

@Paul48 , yeah there's a vent on the left. Video is taken from the right so you can't see the vent that's there.

I've pulled the bonnet off and checked the inside of the valve for anything loose that might be trapping water... nothing there

Oh, also, nuts on all the rods were checked for tightness and snugged up a bit.

@Fred there's some expansion noises in the video, but the loud ones are definitely water hammer.

ChrisJ

Abracadabra said:

1-1/2" steam valve. one of the first things i checked.
vent is a MOM#4 boiler is running at max pressure of 14oz. vaporstat controls 2-stage valve on a WM lgb-13 keeps pressure between 6oz-14oz.
the dark video is early morning. yes, there's a couple degree setback. It's not huge, I don't remember the exact details of the setback they have set offhand. the daytime one i think is midday.

Mark Eatherton said:

Steam collapse? Vapor gets over standing puddle of condensate and collapses in on itself, causing banging? Just the radiator expansion would be enough to wake me up. Maybe try a TRV on that radiator. Grasping here...

ME

I'm grasping too @Mark Eatherton I'm kind of stumped. Got the radiator extremely well pitched, in both front/back and left/right to minimize any condensate sitting in the bottom of the radiator.
I've considered swapping out the radiator with a completely different type just to see if we get anything different. Also as a test, I've even thought about piping the whole thing in 2" down to the stub out of the floor. I'd have to turn the radiator in the other direction though.

Paul48 said:

Hmmm.....Can't see the vent. Maybe the angle.

@Paul48 , yeah there's a vent on the left. Video is taken from the right so you can't see the vent that's there.

I've pulled the bonnet off and checked the inside of the valve for anything loose that might be trapping water... nothing there

Oh, also, nuts on all the rods were checked for tightness and snugged up a bit.

@Fred there's some expansion noises in the video, but the loud ones are definitely water hammer.

Well I'm out.
I bolded what I was about to type next until I saw you already did it.


Here's an idea.
Can you please stop finding weird problems that make no sense?

That would be great.


I'm going to have to fall back on, are you 100% sure the hammering is in the radiator and not the runout below it?

Abracadabra

ChrisJ said:

Here's an idea.
Can you please stop finding weird problems that make no sense?

That would be great.

LOL.... I can handle the easy ones... it's these freaky weird ones that annoy the crap out of me that I figure others would find interesting

Fred

Is there any chance that crud has washed to the center of the bottom of the radiator and created a dam like effect, holding water, on the far side of the radiator, further away from the valve?

Abracadabra

Fred said:

Is there any chance that crud has washed to the center of the bottom of the radiator and created a dam like effect, holding water, on the far side of the radiator, further away from the valve?

Hmm.. maybe.. I'll add this idea to my to-do list.

condensationpoint

Abracadabra, did you make any discoveries in this investigation? I am looking at an almost identical situation and was looking for a similar solution (eccentric reducing bushings), but haven't found such (in the needed size). I would love to hear if you've learned anything since your last post a couple years ago.

the_donut

I had one similar to this. I took a vinyl hose and a shopvac to clean out muck damming radiator. The runout had been pitched wrong but was corrected over a year ago. However all that sludge from the years had washed to one side, about 2 sections in.

Cleaning it out did the trick. Haven’t heard anything in over a month.

Danny Scully

@Abracadabra, is it a modern 1-1/2 hand valve?

Fred

The original post is two years old.

Danny Scully

Lol thanks @Fred. Guess he figured it out

Abracadabra

Put in a new smaller radiator. No more noises, quiet as a mouse.
I've since installed that radiator for another customer and it too is quiet as can be. Guess the old radiator wanted a move to a different home...