Crazy banging and snapping steam radiator

4lane

New this year, one of my steam radiators makes a crazy banging when it starts to get steam and settles down once it foiled with steam and putting out full heat. I replaced the steam valve and pitched it more since I assumed there is residual water inside, hammering. But this didn’t help. Any thoughts?

ChrisJ

We need some pictures.

Thermal expansion? Is the pipe rubbing on wood?

4lane

What pictures are you looking for? It’s pretty standard - no wood rubbing.

Jamie Hall

What @ChrisJ is concerned about -- quite rightly -- is that what you may be hearing is expansion noises. It could be the supply pipe rubbing on the floor. It could be the radiator itself shifting on the floor -- perhaps being pushed by the supply, or just from it itself expanding. It is, after all, clearly sitting on something...

If it is true water hammer, which is also a good possibility, it could be that the inlet valve isn't fully open (this is one pipe?) or that the disc has come adrift and is partly blocking the opening. Or it could be that there is a horizontal section on the supply pipe which isn't adequately pitched any more.

Or...

Fred

Does it actually sound like its banging inside the radiator or is it possible the banging is in the supply pipe below the floor and radiating through the radiator? If it is in the pipe, the supply pipe may have lost its pitch, under the floor. You can correct that by raising both ends of the radiator about a half inch or so and then re-pitching the radiator. Also, make sure the supply valve is fully open.

4lane

It sounds like it’s in the radiator. Metal clanking sound. Valve is fully open and it’s pitched. It’s not rubbing on wood or anything.

4lane

Here is an image of the radiator. Banging and snapping continues. Certainly seems like heat expansion, but what is expanding inside to make that noise?

4lane

Banging and snapping continues. Certainly seems like heat expansion, but what is expanding inside to make that noise?

Jamie Hall

It's not something inside -- unless that is a radiator with inner tension rods -- it is the whole radiator. Is it set really level? All four feet solidly on something? Are the feet free to move? Is the pipe leading to the radiator free to move and not binding on anything?

Can you pinpoint when the noise is occurring? Before the radiator really starts to heat? Just as the radiator starts to heat? While the rest of the radiator is heating up? That will help to figure out what is expanding when the noise occurs -- and hence what it is that's making the noise.

JUGHNE

Did you change the steam air vent or the steam supply valve?
If you still have the old valve, the bottom washer on the stem may be loose or disconnected. It may be laying on the inlet seat and flapping. Usually will not let water drain back though giving you a water flood rad.

Did you raise both ends as Fred suggested, could be the pipe below the floor.

4lane

I changed the steam vent, raised it up and pitched it. No change.

The noise occurs just when steam enters the cold radiator for about 30-45 sec. Once the whole unit is warmed, and it starts to vent, it stops. Here is a snippet of it snapping a couple times (it can get MUCH worse): https://youtu.be/YBDOLBgID3s

ethicalpaul

I vote hammer due to water lying somewhere. If the radiator is actually pitched then I suspect the supply pipe. I have one doing this right now that I have to attend to.

Very helpful recording by the way.

acwagner

To me, that sounds like the pipe is expanding and catching on the structure or hole through the floor.

Remove the escutcheon plate on the floor that is around the pipe coming up. When the radiator is hot (not cold) look at the pipe and see if it's binding in the hole.

Jamie Hall

I like your helper! My first thought is to agree with @acwagner . The timing is such that it's in whatever is immediately under the radiator.

4lane

It's a really hammer striking iron kind of sound. Not wood binding. When it really bangs, the vibrations are strong when touching the radiator, but not at all when touching the pipe/valve.

Fred

Is the supply valve fully open? Are you sure the disc, inside the valve hasn't come loose and dropped down, preventing condensate from getting out of the radiator?

4lane

Valve is fully open, but points on valve preventing condensate from getting out of the radiator is a valid one which I need to investigate further.

4lane

Ok, so I'm back at it. I pulled the radiator out thinking there must be water in it creating hammer when steam first enters it. Not sure why it disappears as soon as it heats up, but... Checked the valve and the seal in the valve is fine and hasn't dropped down - there are no obstructions preventing condensate from returning back into the valve.

So there was this amount of water that ran out when I tipped it over. Should I expect zero water in it? Or is this acceptable?



I also noticed this area on the back which clearly has been where water has run out, as I can also see splatter on the wall a this area. No surprise it made an escape somewhere from the intense banging and snapping it makes. I tried turning this nut (for inner tension rod??) hoping it had worked loose, but it wouldn't budge.





Any thoughts??

Fred

That amount of water is typical. There is a trough in the bottom of the radiator to catch debris. Based on that splatter, I would check the system pressure. Make sure the pigtail that the Pressuretrol is mounted on is not clogged and that the pressure is no more than about 1.5PSI at its peak.
That spot on the radiator suggests to me that water may be dripping out of the radiator vent, hitting that area below it and splattering onto the wall.
What is that clamp I see on one of the radiator fins? Also, When you put that wedge under the foot of the radiator, did you also put one on the leg behind it? Did the popping start after you re-pitched the radiator? You may have pitched the radiator but, in doing so, lost the pitch of the horizontal pipe below the floor. Try raising the entire radiator about a half inch, with a shim under each leg and the re-pitch the radiator.
Those rods that tie the sections together should only be snug, when the radiator is cool, not so tight as to prevent the sections from expanding

4lane

This is the only radiator of 10 that started making this noise all of a sudden. Once it started I repitched it with no change, then raised the whole thing a 1/2” and repitched it, again with no change. That clamp I put on about 8yrs ago when it was making a buzzing/vibrating noise that stopped when clamping those fins together. All the pitching, raising, new steam valve has done nothing to stop this thing from sounding like it’s going to crack in a hundred pieces when it starts snapping and banging.

To me it seems like a heat expansion issue since it only does it at cold when hot steam first starts flowing in and stops after a minute or two once the whole thing is warm. But I don’t know what it could be and how to fix it. Maybe the

Fred

@4lane , what size vent do you have on that radiator? This is a good article from Dan. While it speaks to large radiators, the effect of fast venting, even on a moderately sized radiator can have the same effect. Did you add a faster vent on that radiator just before the noise started?
https://forum.heatinghelp.com/discussion/178506/air-vents-and-oversized-radiators#latest

4lane

It had a Gorton #4 on it the past 10yrs, and when it started knocking. I took it off and put an adjustable replacement on it but it didn't change anything. Plus it's currently spitting water. Although there was nothing new introduced in the system, I'll look in my inventory for some slow venting sizes or put the current one on it's slowest setting per this link. Thanks for this.

neilc

sorry if I missed it,
did we answer the boiler pressure / clean pigtail question ?

Fred

neilc said:

sorry if I missed it,
did we answer the boiler pressure / clean pigtail question ?

Not yet.

GaryS

I had the same problem after repairing the floors under a few of my radiators, sounded like dueling church bells. I tried most of the suggestions above (and a few other things) with no success. Finally put some of those felt stick-on furniture pads under the radiator feet....no more banging.
Hope this helps.