Steam Pipes Banging

CSRD · January 16

Recently moved into an older apartment in Central MA with steam radiators.

Boiler is a few years old. Has had maintenance yearly according to our landlord. From the beginning when we turned the heat on in November, we had one radiator that was spitting water from a vent and you could hear water clanging around in others.

The landlords HVAC company has

-Pitched the radiators

-Replaced all the vents on all the radiators

-Put some kind of chemical in the boiler to break up clogs and then flushed the boiler.

Since they flushed the boiler and temperatures have gotten into the twenties, the pipes have started banging horribly when the heat turns on. We no longer hear water clanging in the radiators and it now seems to be coming from the pipes. All of the new vents have also started spitting murky colored water.

We had been leaving the heat around 62/64 when we are home and awake and around 58/60 when we are asleep or at work. The HVAC company said the pressure was too low on the boiler and increased it. They also told us that we needed to leave the heat at one temperature all day, ideally 67 plus to keep the water from condensing in the pipes and creating the noise when the heat turns on. Then they basically told us they are out of ideas. I am very hesitant to heat the apartment to 67 plus all day when we are gone most of the day due to the high cost of utilities here.

We tried turning up the heat to 65 and didn’t adjust for a day and half and there was no difference in the noise level. It just happened more frequently because the heat was coming on more frequently. It sounds like someone is hitting the pipes with a hammer but there is also a sound like water ricocheting.

It seems about the same as when we had heat at 62. The vents are also spitting out more water than before they changed the pressure.

I am wondering if anyone has any other ideas about what could be causing the noise or insight into what the HVAC people and our landlord are telling us.

Do we really need to keep the temperature at least 67 to keep the system working properly and prevent noise?

We have also been told that it’s best to keep it at one temperature all day and not set back when we are asleep or out. Is this true? Is a small set back not possible when we are not home or sleeping?

We are at loss and our landlord just wants us to turn the heat up, but he doesn’t pay the gas bill. He is basically saying there shouldn’t be a problem because the boiler is new and previous tenants didn’t have issues.

I am considering also paying someone myself to come look at and get a second opinion if anyone has ideas for HVAC/Plumbers in the Central MA area who are knowledgeable about steam heat.

Grallert · January 16

Keeping the temp up isn't going to help. The steam is still going to condense, that's it's job. Increasing the pressure is just wrong. It's likely the boiler is tossing water up into the piping when it boilers and that water is not getting back to the boiler correctly. Can you post so pictures of the "new" boiler and the piping around it?

CSRD · January 16

ethicalpaul · January 16

The piping above the header isn't really right but it should be able to perform OK.

I would suspect the water quality and also the water level is quite high. One or both of these may be resulting in water being "carried over" up into the header and the rest of your system.

Please watch the boiler at the start of a call for heat and see if the water level drops more than about 1/2". If it does, that's a strong indication of carryover/surging which can definitely cause banging and other problems.

Looks like a counterflow installation which does make the piping size more critical, but again, I think your existing piping can perform OK even though it's not right.

BobC · January 16

Sounds like that contractor does not understand steam. The piping has issues but I don't think that is youe problem. This is a one pipe steam system so pipe pitch is important, check all your pipes in the basement and see if they consistently pitch back to the boiler.

Does the water line in the sight glass jump around when it's making steam. If so there is oil in the water and the boiler has to be skimmed - drain and refilling it will not help, it needs a nice slow hot skim to float any oill out of the boiler. If that seems to work but the boiler starts to bang again after a couple of days it needs to be skimmed again.

Bob

bmma · January 16

If the boiler is new, I'd be willing to bet that they didn't skim it correctly, or at all. Oil floating on the water in the boiler can definitely cause the problems you are experiencing.

Firstlook · January 16

my 2 cents

The water level in sight glass looks a little high.

Check for leaks especially Look at each radiator valve control for leaks

I have the same steam boiler and its was the radiator steam valves leaking and you get the awful air hammering.

Jamie Hall · January 16

You mention that your HVAC company seems to be out of ideas. I'm not sure they ever had any…

First, get your pressure down — the cutout pressure should be less than 2 psig. That should be easy enough to do.

Second, if they put "something" in the boiler to break up clogs etc. etc. you need to empty the boiler completely (when it's cold!) and flush it with clean water a couple of times and refill it with fresh water. Some advocate a small amount of treatment, such as 8 Way, to control the pH — but always much less than the bottle says — and some folks don't.

Then skim the boiler as has been mentioned above.

While you are doing all that, wander around the basement and check, as best you can, that all the piping is pitched so that any condensate which gets into it can drain back out to the boiler somehow. You don't want any pooling.

Now there is a bit of bad news: the vents which were spitting murky water may have been damaged by that murky water. If you find that they don't close properly, you may need to replace them — but only with quality. The vents in the Big Box store are not good enough.

CSRD · January 16

https://forum.heatinghelp.com/discussion/comment/1835239#Comment_1835239

I just turned it on and it went all the way from the top to almost all the way to the bottom of the glass. The water when it went down also was foamy on top.

I don't know if that's because I turned it on after being off for a while(we haven't been able to tolerate the noise).

ethicalpaul · January 16

no that’s not why. Off time shouldn’t affect anything

The water probably has oils in it. It needs to be skimmed

Steam Pipes Banging

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