Banging pipes

hugsnchris

I have a gas boiler and steam heat through out the house, I'm getting this tremendous banging that drives us crazy coming from the radiators and the pipes in the basement. My question is should the radiators be tilted towards the return pipe or should they be level and is there a way of blowing them out?
Thanks

JUGHNE

If there is only one pipe connected to the radiator then the rad should tilt towards the inlet valve.

Post pictures of the typical rad you have.

What pressure shows on the gauge on the boiler?

Jamie Hall

Banging such as you describe is from trapped condensate in the pipes and sometimes the radiators. All the steam pipes must be pitched -- sloped-- so that the water can drain easily back to the boiler. I'd start off (once the radiators are pitched properly -- doesn't have to be much) by going through the system, pipe by pipe, and making sure that any condensate can drain.

You might also want to buy the little book "We Got Steam Heat" -- it's available from the store on this site or from Amazon.

hugsnchris

Jamie Hall, I purchased the book We Got Steam and the first thing I noticed was in the book they are talking about Main Vent valves on the pipes in the basement I checked and there aren't any. I'm figuring this may be the place to start by installing 2 of these vents on the feed line. Any advice? Thanks Hugo

Jamie Hall

hugsnchris said:

Jamie Hall, I purchased the book We Got Steam and the first thing I noticed was in the book they are talking about Main Vent valves on the pipes in the basement I checked and there aren't any. I'm figuring this may be the place to start by installing 2 of these vents on the feed line. Any advice? Thanks Hugo

Somehow that doesn't surprise me... The first thing for you to do -- with the aid of that little book! -- is to get a very clear idea of what each of the pipes does and where it does. Then you should be able to identify the steam main or mains, and determine which direction the condensate might flow in them -- you need that to figure out where it might be getting stuck, which could be your hammering. And then you also need to see where -- at or very near the end(s) of those -- you can put vents. Which you do need. The vents are sized to the length and diameter of the mains.

JohnNY

Banging basement pipes is often an indication of either a clogged return pipe, or an unwanted rise in pressure for a variety of reasons. Best to have the system checked out by a proper steam professional.

hugsnchris

Jamie I'm trying to understand what you are saying. When you speak of the end of the run on the mains it seems there are 2 mains one going to one side of the house and another running to the other side, neither of them end they just continue onto the radiators. I'm enclosing some pictures of what I'm assuming are the mains and the only place I can see a vent valve going also a picture of the gauge which doesn't move and a pressure control which I have no idea what that does. I appreciate your help, Thank You.

Jamie Hall

Well let's see here.

Easy things first. The pressure gauge. I'm not surprised it doesn't move, or move much -- that's the 0 to 30 psi gauge which the code requires. Don't worry about it.

The blue box is what is called a Pressuretrol. It's job is to regulate the maximum pressure which the system will operate at. There are two scales on yours. The one on the right sets the pressure at which the boiler should shut off; the one on the left sets the difference in pressure between where it shuts off and turns back on again. In your case, the shutoff pressure is set much too high. There is an adjustment screw at the top of each scale -- your's has an ominous label on it saying to not alter it, but if you're feeling moderately brave, find the screw above the right had scale and try, by turning it, to move the indicator down to about 2.

That assumes, however, the pressuretrol can sense the boiler pressure. It is connected to the boiler through that curly pipe below it, which is called -- not surprisingly -- a pigtail. There is a good chance it may be clogged. It will be a bit of a chore to get it all apart and check it, never mind clean it.

It would do you no harm to get a qualified steam heating contractor out there to check and adjust the burner, clean the boiler, and while he or she is at it, clean the pigtail and check that the pressuretrol and low water cutoff (the box labelled "Cyclegard") actually work. I have a suspicion (perhaps unjustified) of a lack of maintenance here...

Now to the piping. You have identified that you have two steam mains -- one to one side of the house, the other to the other. A very common arrangement, by the way. Without looking at the whole piping, I can't be sure -- but I doubt that there is a vent on either one. Further, without looking at all the piping, I'm not quite sure where they might be put. There will always be a way, but it may not be obvious -- or particularly straightforward. That same steam person I mentioned will be able to determine that.

What I do see is the potential for lots of sags. You need to assess the whole piping layont, and figure out which way the water in those pipes (it isn't much) -- towards or away from the boiler -- in the original installation was meant to flow. Once you figure that out, you need to check every bit of that piping -- all the way out to the radiators -- to make sure that there are no low spots -- sags -- in it. You may have to add additional pipe hangers here and there to get it that way.

Some pictures showing all the piping around the immediate vicinity of the boiler would bee helpful.

mikeg2015

You can start by turning the pressure and differential down.

I’d guess a lot of the banging might be failed steam traps allowing steam into the return. This caused by balance issues, venting issues, traps need rebuilt and quite likely the boiler is oversized as well.

Some 2 pipe systems were vapor systems and condensate returns using loop seals will not function right above 2psi.

Steamhead

@hugsnchris , where are you located?

Tim_Hodgson

Mike and Jamie are giving great advice. Hoffman had a steam differential control that dumped steam from a steam supply pipe into the condensate return to keep the steam pressure within 2/3rd of a pound of the return.