Banging pipes

enalevanko

My main steam pipe continues to fill with water causing pipes to bang. I have a one pipe steam heat system with no auto feed. I open the pipe at a u joint connection and let out about a gallon and a half of water. On the next call for steam the pipes do not bang. On the second run the pipes bang. I have been opening the u joint every other day as the problem continues. What is causing this problem? Thank you.

EBEBRATT-Ed

@enalevanko

All steam pipes are supposed to be pitched to drain so they should not "hold" any water. Post a few pictures of the "u joint" so we can see what is going on

enalevanko

enalevanko

Presently disconnected as I have just drained the water.

EBEBRATT-Ed

With the drop ceiling it's hard to see the pipe pitch. I would suspect when the ceiling was installed someone raised a pipe and changed the pitch, unfortunately now the pipe does not drain.

Put the pipe back together and check it with a level.

On most systems the steam pipes start out high at the boiler and pitch down as they go around the house back to the boiler return.

There are counterflow systems that drain back to the boiler through the supply. Take some pictures of your boiler and the piping around the boiler so we can se what is going on

enalevanko

I put the ceiling up around the pipes and never changed the pitch. New furnace installed two years ago and the pipe with the joint right after. I will add some pics of the furnace.

enalevanko

JUGHNE

Can you back up for more pictures?
Floor to ceiling from all sides possible.

enalevanko

ethicalpaul

Ok just for ease of communication that’s called a “union”

your near boiler piping is incorrect and may be throwing water into your main.

but that is secondary in my mind to the question of the pitch of your main. If you are opening this some time after your boiler runs (like a 1/2 hour later) there should be no water in it. As said above, there must be no “valleys” in your main

enalevanko

After connecting the union I put a level on the main and it is pitched back to the furnace. What is wrong with the near boiler piping and what needs to be done to correct it?

JUGHNE

There may be comments that your piping at the boiler is wrong, well it is, but it worked until lately....correct?

The steam pipe above the boiler looks to be the high point of the main and the return looks to be the low point of the horizontal piping. That piping should be continuously slopped from the boiler back to the return without any dips or sag. A little dip can go a long ways in making a problem.

The first thing I would check is the little garden hose bib on the lower wet return piping, (about 24" long).
See if water flows out of it freely.
The U shaped piping which is about 18" high on each side is a mud trap. You should be able to drain only about a gallon of water out of that hose bib.
If it is partially plugged then the water will back up in the return and steam main.
If you get it to drain you could give a few shots of fresh water with the fill valve to break more of it loose. You do not want to wash sludge up into the boiler.

You could always open the union but it would be best to get it to drain first.....nasty sludge probably in it.

JUGHNE

So from the union you open will the water drain back to the boiler or to the end of the pipe? Or both is possible.

enalevanko

Yes it did work until furnace was replaced. I have been letting water out of the hose bib while the steam is going into the main (read somewhere to do that) and water is coming out freely but dark and murky. From the union the water would drain back to the furnace.

JUGHNE

It worked OK until the boiler was changed....2 years ago?

It is possible that when the boiler was changed they pulled the piping down to fit what they had on the new boiler.
The steam riser could be 1-2" longer, (the nipple above the union) and a longer nipple on the equalizer drop pipe above the union. (12-14")

You should have an install book with this boiler 50+ pages.
It would show the recommended piping.
Some one did not open the book, it could be laying around in the basement. You can see it on line also.

enalevanko

Yes. So the piping above the furnace is incorrect causing water to get in the main, correct?

Jamie Hall

That's one of the problems, anyway. But I'm concerned about the overall drainage of the steam main. If that union is a high point, there is no way it should hold water. Clearly, if you open it and water drains out, it's not a high point. You really need to start at the boiler and go all the way around the basement following the main until it comes to the end, apparently back at the boiler. It must be one continuous even slope all the way around.

enalevanko

Is the main supposed to slope back to the boiler, away or level?

Jamie Hall

It could either go back to the boiler or away, but it must be consistent. If it does go back to the boiler, there must be a drip to the boiler return before the riser from the header gets to it. Yours doesn't have that, which leads me to suspect that it should slope away. Evenly. All the way around. It is never level.

JUGHNE

The boiler before this was probably piped in this same incorrect manner. But if they lowered the main above the boiler then that would compound the problem with the wet steam you are probably putting into the main from the incorrect piping.

If you find the book you will understand what we mean about bad piping at the boiler.

enalevanko

Thank you for your help. I will call in a plumber (not tHe installer) for assistance on re piping at the furnace.

ethicalpaul

Beware all plumbers. If you call someone, call a steam professional from the “find a contractor” page of this site.

otherwise you risk spending money to not fix your problem.

PS: the “boiler” it is called. 

PPS: I think everyone in this thread recommended finding out what’s going on with the pitch of your main pipes before worrying about the near boiler piping quite yet (although you may find there is a relationship there)

JohnNY

Isn't there a larger issue here? What is going on with this boiler's flue? Reduced in diameter twice and a draft inducer added to allow the boiler to vent to a side wall 6" from a window?

So not right.

mcrabbit98

Are the contractors listed vetted as steam specialists or just pay to advertise here? I need a steam specialist in Merrick LI area. I replaced my boiler 4 yrs ago. I had a tenant in the house who never complained about banging pipes (which I didn’t have prior to boiler replacement). Since heat has been on the last 5 weeks and I’m here now, the banging is intense. I had the installer (local plumber) come to check it out and he added SCOUT cleaner, told me it would take 2 wks to work. It’s 10 days now & still banging and trying to sell the house. Pics of original boiler & new boiler attached. Recommendations please? Does anyone know good steam heat specialist on Long Island in NY.

Jamie Hall

The folks who advertise on here do pay for the privilege. Someone has to pay to keep this Wall going... and I thank them all for their generosity! That said, most of them we know -- some personally, some by reputation, and they are all good. Some are superb.

I couldn't say who would work in Merrick. New York's licensing regime is a bit odd, and someone who works in one town might not in a town next door.

As to your boiler... we've seen worse. In fact, on the whole it's not really that bad. However, Scout isn't going to help the banging. There's a pressure control on the boiler -- which I can't see -- but make sure that it is set to cutin the boiler at a bit above half a pound and cutout a pound higher.

Also you may have a problem with what were, with the old boiler, wet returns. These are pipes which are below the water level in the boiler, and it is intended that they be full of water at all times. That new boiler is a lot shorter than the old one was, and it is quite possible that some of what should be wet returns are now dry, or partly dry. This can give some horrendous banging. It is possible to fix the problem, but it isn't completely straightforward.

In general, banging is caused by water collecting in a pipe and not being able to drain freely. Therefore, you can start at your boiler and go along all the steam pipes and make sure that they can all drain freely back to the boiler. All the steam pipes. But I'm thinking that when the new boiler was installed the pipes got either raised or lowered and disrupted that.

mcrabbit98

Thanks Jamie, this pic is what you’re referring to I guess. And also a screenshot of local contractors listed on this site. Any known to you? 

“Are the contractors listed vetted as steam specialists or just pay to advertise here? I need a steam specialist in Merrick LI area. I replaced my boiler 4 yrs ago. I had a tenant in the house who never complained about banging pipes (which I didn’t have prior to boiler replacement). Since heat has been on the last 5 weeks and I’m here now, the banging is intense. I had the installer (local plumber) come to check it out and he added SCOUT cleaner, told me it would take 2 wks to work. It’s 10 days now & still banging. I have Pics of original boiler & new boiler but not sure how to attach. Recommendations please?”

Jamie Hall

Yes -- if @Danny Scully serves, your area, I know of his work and regard him as one of the best.

bdl

Isn't Diff supposed to be less than Main on this kind of Pressuretrol?

Jamie Hall

bdl said:

Isn't Diff supposed to be less than Main on this kind of Pressuretrol?

Yes. The differential is subtractive. If it's greater than the main, the control may not reset after cutting out. Somebody can't read or do arithmetic. Or both. Reset the differential to about 0.5. Also, the main is a bit conservative for a conventional steam system -- try it at about a quarter pound higher.