Steam Pipes banging after renovation

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Old 11-23-12, 06:40 AM
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Steam Pipes banging after renovation

Hello,

Seeking advice to boiler water level and pipe banging problems. (Going to be detailed here so you understand what I may have done to cause this ...)

This summer we renovated our basement. The heating system is a 3 year old Utica boiler (2 zones) that feeds the first story baseboard hot water and second story steam. We never experience banging steam pipes prior to the renovation.

Previously, the basement had 2.5" pipes that were primarily the old manifold that fed the first story. There were two legs to this manifold piping, the main one that fed the first floor was all capped except at the end which leads to my daughters bedroom on second floor. The other feeds my bedroom, bath and my sons bedroom also on second floor. (untouched)

In the basement, we cut out the manifold that led to my daughters room and replaced with 1 1/2 dedicated pipe (about 22 feet).

For the first month the heat was on I did not hear any banging and the furnace work fine. One morning, the furnance was out of water and the heat did not come on so I added water.

We had a few cold nights were everything worked without issue but now that it is colder we are hearing banging in the middle of the night. Like a sledge hammer! It seems like the colder it is the more this is likely to happen.

The Banging is occurring on the leg of pipe we replaced.

The pipe before it turns upward has a T that brings the return pipe down to the floor level as a return. We kept this return but previously there was an air valve that was removed. I didn't understand why we needed it since there is a valve upstairs in my daughters room. And this would have been inside the walls. which I did not want.

Another odd symptom to note:

After the boiler ran out of water (It was quite low) I added water. the heat came back on and then the water glass showed too much water. So I removed some.

Since this occurrence, I have had a hard time balancing the water level which seems to fluctuate more then I recall in the past and I think the pipes bags more when the water level is on the high side. Also, because the water level is fluctuating, if I don't keep it higher the low water sensor kicks in.

I guessing that the water is sitting in the pipe and that this is why the water level is fluctuating...

My fear is that I will need to open up my basement walls and ceiling and add more pitch to the pipe leading to my daughters room and perhaps add back in the air value. This would be a very big job and I would like to avoid it at all cost. The pipe we replaced had a slight pitch but was mostly not pitched.

Since the boiler was working with no banging for about a month, I want to believe that there is some kind of adjustments I can make that wont require me to open up walls..

Is there something else I should try first?

Last, aside from waking the entire house, is banging bad for the steam Pipes?

Thanks so much!

Curtis
 
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Old 11-23-12, 07:18 AM
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I'mj certainly no expert in steam, but I know you shouldn't mess with the piping willy nilly. The size of the piping and layout are very important for the system to operate properly. You removed an air vent? That certainly isn't good either. You might want to read the info here: Technical Menu

So your system has hot water baseboard on the first floor and steam on the second? Why not hot water on the second?
 
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Old 11-23-12, 07:45 AM
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Aside from the points that Droo brought up, I'm wondering if there could have been enough oils left over from the manufacturing process in the new pipes that might necessitate having to 'skim' the boiler to remove the oils. These oils can cause surging water levels in the boiler. This is because the oil forms a layer on top of the water that prevents the steam from leaving the surface...

I guessing that the water is sitting in the pipe and that this is why the water level is fluctuating...
Possibly ... but the water sitting in the pipe is more likely the reason for the banging, it sounds like the system has a 'wet return' (I know about as much as droo does about steam, keep in mind), but if the pipes are 'flooded' you will have problems.

I didn't understand why we needed it since there is a valve upstairs in my daughters room.
Never guess, and never 'second guess' an installation by someone who KNEW what he was doing and why he did it.

The pipe we replaced had a slight pitch but was mostly not pitched.
I believe that at LEAST 1/2" per foot of run is the proper pitch for a steam pipe.

is banging bad for the steam Pipes?
Think about this: How hard would you have to hit those pipes with a sledgehammer in order to recreate the noise you hear?

Yes, the banging can crack and break the fittings.

I think your strategy at this point would be to properly 'skim' the boiler to remove any oil, and get the water level under control. Maybe this is all you need to do... maybe.

I always recommend this book to owners of steamers, it's the best $25 a homeowner can spend on their heating system. You will learn about proper settings, functions of all the components, and most of all, who to trust and who not to trust working on your system. After you read this book, you will likely know more than 90% of the so-called 'techs' that come to work on it:

Heating Help
 
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Old 11-23-12, 01:01 PM
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In response...

Thx.

I will in investigate the suggestions you have made, particularly skimming the system. Can I assume that this would be the same a draining/flushing the system?

I'm still wondering why I had about a month of operation with at least 5-6 cold evenings where heat was called for yet there were no issues.

I definitely did not pitch the pip 1/2 inch per foot. it was more like 2 inches over 15 feet.

Regarding The system being a split system ( baseboard and steam) This is how it was when I bought the house . I considered getting rid of the steam but there is no easy way to plumb the second story with a return and so I left it as was.
 
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Old 11-23-12, 03:02 PM
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The mainline vent must be after the last riser and the entire pipe needs to be insulated.
By the bouncing of the water level you stated the system needs to be skimmed not drained as that will achieve no benefit.
Make sure the second floor main line vent also works well.
 
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Old 11-23-12, 03:06 PM
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Can I assume that this would be the same a draining/flushing the system?
No. Draining/flushing takes the water from the bottom. Skimming takes the water from the TOP, where the thin layer of is.

You may have to install a valve in order to properly skim if there is not one already. There should be a tapping on the boiler somewhere, at or just above the water line. The idea is to SLOWLY skim the surface water off the top to carry the oils with it.

Search this forum for posts on how to skim... there have been a few in the past couple months. At least one that I recall had some pretty good instructions.

And, BUY THE BOOK!
 
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Old 11-23-12, 03:17 PM
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I will in investigate the suggestions you have made, particularly skimming the system. Can I assume that this would be the same a draining/flushing the system?
No! See this link on skimming: Skimming a Steam Boiler

I'm still wondering why I had about a month of operation with at least 5-6 cold evenings where heat was called for yet there were no issues.
Colder weather means longer run times. That will amplify any problems with the system.
 
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Old 11-23-12, 03:28 PM
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Colder weather means longer run times. That will amplify any problems with the system.
True that... and it may have taken some time for the oil in the new pipes to make it's way back to the boiler.
 
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Old 11-24-12, 04:38 AM
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Thanks again.

Yes, I have read all links and it's making sense to me although I'm not sure I want to take on the boiler myself.

Sounds like I may need to add back in the main line vent too, but I will try skimming first. This would be least invasive to my finished basement as oppose to opening up the walls and ceilings. Oh well trial by fire.

Fingers crossed.
 
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Old 11-24-12, 08:44 AM
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I'm not sure I want to take on the boiler myself.
What do you mean? " ... take on the boiler ... " ?

If you mean that you don't want to read the book, well, reading the book does not mean you will be " taking on the boiler ".

The book will educate you in layman's terms as to how the system operates, what to expect when repair people arrive, how to tell when they are bullpooping you, how to tell if they are idiots and when to show them the door, etc...

READ THE BOOK! You will NOT be sorry!
 
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Old 11-27-12, 02:39 PM
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What did you replace the pipe with? Copper? More than likely you have a belly somewhere in the piping you replaced if it is with copper. Hopefully you used enough hangers and you need 1/4" per foot if your pitched away from your boiler and 1/2" per foot if its pitched toward the boiler, this depends on the type of system you have but with a wet return at the end its gonna be the 1/4" per foot away from the boiler. That so called wet return isn't taken off where the vent was correct. If you used that as a return the whole line will fill up with water. Other issues you may have are venting, system being dirty, boiler oversized. The list goes on. You shouldn't mess with steam unless you know what your doing. Sorry to say, but you should have a steam guy take a look at your issues.
 
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Old 12-11-12, 05:39 PM
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I've lived in our two story 80+ year old house with a steam boiler system for many years. I took me some time to eliminate all banking, both before and after a replacement boiler was installed. Regarding the possible oil issue and need to skim the boiler, it is normal for the slight glass level to move a little, 1/4 -1/2 inch. If it is bouncing around more than that, than you definitely need to skim the boiler. Can you get your contractor to do it, as he should have checked the new pipes and fittings during the installation? Is there still a slight pitch in the bedroom radiator?
In my experience, adding one of the safe cleaning additives and then draining a few times also helped.
 
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