Steam heat - Loud banging noise from the pipes


Old 12-17-08, 08:00 AM
Join Date: Dec 2008
Location: New Jersey
Posts: 24

The vents affect how quickly the steam is distributed by controlling the rate at which air is expelled from the piping/radiators. Once the air is out and steam has filled the system, the pressuretrol determines the operating pressures, and lower is preferable.

If you have the typical Honeywell PA404A, set the pressuretrol to 0.5psi. You can also remove the cover and turn the dial to the lowest setting (1 or 1.5) psi differential.

Last edited by Steve Raft; 12-17-08 at 08:17 AM.
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Old 12-17-08, 09:49 AM
Join Date: Dec 2008
Posts: 3
You are correct Steve. I do have the PA404A. The information you gave me sounds great. I will try this tonight when I get home. Thank you so much
Old 12-17-08, 09:54 AM
Join Date: Dec 2008
Location: NJ
Posts: 3
Is there anything to help with noisy pipes in the floor?

One pipe steam system in 1920s house, finished basement.

When the heat kicks on, I get pretty severe banging. It isn't at the radiators themselves, but I think it is in the two heating pipes that run in the floor between the first floor and basement. Is there anything that can help this without ripping up the ceiling in the basement?

Old 12-17-08, 01:21 PM
Join Date: Dec 2008
Location: New Jersey
Posts: 24

Did your system ever run without the banging? If so, what has been changed?

Anyway, sounds like too much condensate in the mains. This could happen for the following reasons:

1) Pipes are no longer pitched correctly due to broken pipe hangers and/or house settling.

2) uninsulated main pipe(s), which will condense steam 5 times faster that insulated pipes

3) the wet return leg is plugged and condensate is spilling into the main.

Is the banging happening at the start, middle or end of the heating cycle?

These are relatively easy fixes, albeit you'll have to open up the ceiling if condition 1 or 2 exists in your house.

If the near-boiler piping was incorrectly installed, then that's a more expensive fix, but if the system ran quiet in the past, then that's not a likely problem
Old 12-17-08, 02:13 PM
Join Date: Dec 2008
Location: NJ
Posts: 3
There was always banging. I'd say it's gotten somewhat worse the past year or two (and somewhat worse since a section of very old, leaking pipe iron pipe was replaced with copper). I know the only pipe insulation is on the pipes very near the boiler. Once the pipes exit the boiler room they are uninsulated (except for the walls themselves).

I think it is likely scenarios 1 and 2. The banging is at the start of the heating cycle only.
Old 12-18-08, 05:50 AM
Join Date: Dec 2008
Location: NJ
Posts: 3
Would new pipe hangers (actually...I don't think there really are any pipe hangers now) be likely to make any difference?
Old 12-18-08, 07:43 AM
Join Date: Dec 2008
Location: Elgin, IL
Posts: 1
Wow, great forum. I wish I had checked it out before I had my boiler replaced.

Here's a quick recap. We bought our 1929 home in March of this year. With it we purchased the steam heating system that had been in place since the home was built and that was converted first from coal to oil and then to gas sometime in the last 80 years. We knew that the system would need to be replaced at some point in the near future but we were hoping that it would make it through this winter at least. Well, to make a long story short, it wasn't meant to be and we soon discovered we needed to replace the old boiler. One of the reasons was that it would not retain the water and we'd have to refill it every three to four hours (there was not automatic water feed) in order to keep our home warm.

So I obtained quotes from three companies and finally decided on the one business that friends recommended to us, that offered the best deal and that had been in business for almost a hundred years. The entire process with this company, from obtaining the quote to the installation, was very pleasant. The thousands of questions I had were always answered promptly and they fulfilled all the promises they made.

Now, I did run into a problem though. Our old boiler was replaced yesterday and when the job was finished we could immediately tell a difference between the old and new system. Unfortunately not all of the differences were positive. We were awakened in the middle of the night by some really loud banging noise, something we had never heard before. I knew it was water hammer but was a little surprised because we had had never experienced it before in the home and I wasn't really expecting anything like this after having just had a new steam heating system installed. The banging didn't last very long, maybe 30 to 60 seconds but it was very intense, at least I thought it was. Right before I wanted to leave for work this morning the banging all of a sudden started again and I noticed that the boiler had just kicked in previously, which leads me to believe this must be happening at the beginning of every heating cycle. When I went downstairs to look at the boiler the banging got louder and seemed to be coming from one of the pipes close to the boiler and the entire unit would vibrate whenever the banging occurred.

I immediately called the company that installed the boiler and they're sending someone out this afternoon to take a look at it. They think it might have something to do with the water level and that it might need adjusted. I did notice that the water level in the sight glass was fluctuating anywhere from being 1/3 to 2/3 full.

Does anyone know if the water level could really cause such a loud banging noise or would something else be causing it.

Thanks in advance for any input anyone might be able to offer. I'll let you know what the company finds this afternoon.

Old 12-18-08, 09:45 AM
Join Date: Dec 2008
Location: New Jersey
Posts: 24
If the pipe hangers have sagged, or broken off, then the pipe will not be pitched properly and/or may have small areas that have drooped and can retain pockets of water. When the steam hits these pockets the banging will start and continue until the pipe is hot enough to vaporize any standing water. With no insulation, your adding extra water to the condition.

Recently, I replaced the asbestos insulation with fiberglass and for about 2 weeks the mains were uninsulated. The banging was waking us up in bedroom, two floors up. As soon as I re-insulated the water hammer stopped.

Originally Posted by tdelet View Post
Would new pipe hangers (actually...I don't think there really are any pipe hangers now) be likely to make any difference?
Old 11-02-09, 05:44 PM
Join Date: Nov 2009
Location: chicago
Posts: 1
loud banging in steam pipes

Our building has 11 apartments, and I'm running a coffee shop, at the first floor, and 11 apartments, upstairs.
Heating is steam based, boiler in the basement.
The condo association, had some, repairs done at the boiler, gas valves replaced, and water feeder replaced also,
Now, everytime the heat is ON, a huge banging on the pipes, extremely loud, unbearable, and I also can hear water, running through the steam pipes.
I checked the boiler, is flooded, so i release the water, and it works for a half day OK, then the banging is back.
everytime I check the water level, is all the way up, on the glass indicator.
A year ago, I had the noise problem, but only after 7-10 days of heat running, I just released water and it was fine for more then a week.
Now I have to do it 1 or 2 times a day.Something is not right , i told manager, they don't want to do anything, they say 2 different companies checked the boiler, and it looks OK.
It is not OK, water gets too much in the boiler, and banging is unbearable,management said the apartments above have malfunctioning valves, and that is why the banging happens.
Old 11-02-09, 08:47 PM
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,443
Likes Received: 9
The Chicago Municipal government website is having problems so I couldn't get the information I needed but I'm pretty sure that you need to be licensed to do any work on a steam boiler in a mixed use commercial building. If you are not licensed to operate or maintain a boiler then you could be (most likely are) in violation of the law with your DIY fiddling with the boiler.

If the building owner won't respond to your requests to have the boiler and heating system repaired then I strongly urge you to contact the Chicago Building Department and request to speak with a boiler inspector. I can almost guarantee that if the system is as bad as you state the inspector will red tag it and then the owner MUST get it properly serviced.

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