Banging steam radiator

Homeplumbinghelp72

My contractor has been trying to fix the banging noise for months but has failed. This is how it looks now but continues to make banging noises. He said it’s because the previous radiator in its place was bigger and the problems are because of the size of the radiator. Can I please have your thoughts on this? Thank you. 

Ironman

Banging is caused by water pooling somewhere in the steam piping. The steam picks it up and slams it against the piping.

You need to find where the piping is sagging or not pitched correctly. The radiator should also be pitched back toward the valve on a one pipe system.

KC_Jones

The size of the new radiator compared to the old is completely irrelevant to the situation.

As said it’s water pooling somewhere, heating it physically in the radiator doesn’t mean the problem is with the radiator.

In addition to that, your contractor installed the vent in the wrong place. It should be installed about 3/4 down from the top of the radiator. I can see the boss that needs drilled and tapped in your picture (circled below).

ChrisJ

Can you describe this banging and when it happens?

I.E. does it only happen for a short time as the radiator first gets hot? Does it happen again after the boilers off and it's cooling at all?

Or, does it happen when the radiator is almost or completely hot all the way across?


How tight is that block of wood between the wall and the brass valve? Is it jammed in there really tight?

Is the valve completely open?

Homeplumbinghelp72

ChrisJ said:

Can you describe this banging and when it happens? I.E. does it only happen for a short time as the radiator first gets hot? Does it happen again after the boilers off and it's cooling at all? Or, does it happen when the radiator is almost or completely hot all the way across? How tight is that block of wood between the wall and the brass valve? Is it jammed in there really tight? Is the valve completely open?

Thanks. So the banging happens when it first gets hot and not during cooling. Essentially when steam first starts entering, it bangs for a minute or two and then just rattles quietly. 

The block of wood between the wall and valve is quite tight. Should we loosen it?

valve is completely open. 

Plumber is moving the vent half way down as per the previous comments. 

KC_Jones

You don't want any wood touching anything that can expand, which is all the pipes and the radiator. The wood will attempt to limit the expansion and contraction and make noise.

Without hearing what is going on it's hard to say for sure, but the banging you are hearing could be from that. Given that you say it's primarily at the beginning of the cycle would strongly point to this.

I would say remove the block of wood (I'm not understanding it's purpose anyway) and any other location that may be touching wood add some pieces of plastic milk jug (or similar material) to act as a slide so it doesn't make noise.

ethicalpaul

Without hearing what is going on it's hard to say for sure, but the banging you are hearing could be from that. Given that you say it's primarily at the beginning of the cycle would strongly point to this.

Not disagreeing because it could be the wood, but water hammer would also be at the beginning of the cycle in this case I believe (once the sitting water is heated, the banging stops)

bburd

That is a notoriously fast vent. A slower one may help the radiator heat and produce condensate more slowly.

Mad Dog_2

Hoffman # 40 is the perfect slow-venter   Mad Dog 🐕