Clanging pipes in steam radiator system

Sleepless_in_Stl

I own an old house in St. Louis that we converted from a two-family to a one-family.

We have two seperate heating systems.  For the second floor we have steam radiators, single pipe.  The boiler is a 1999 model but the pipes and radiators are original.  The system worked fine with twice yearly maintenance until last year.  We developed horrible clanging.  The pipes are insulated expect for the last section of the return pipe.  I repalced the main vent with a Gorton #2 thanks to a knowledgeable friend.  The system is venting and the heat works fine but the clanging keeps me up all night.  I flush the system of dirty water regularly.  I am guessing it needs it too often.  I could practically do it daily.  I have tried to find a St. Louis based contractor who really knows steam systems to no avail.  Can anyone recommend a St. Louis based contractor who really knows steam and isn't going to fake their way through a service call.  I can't take it anymore!

BobC

Pressure and slope

I don't know anyone in St Louis but there are a few things you can check on.



What pressure is the boiler operating at? What is the pressuretrol set to? It should be 2PSI or less for quiet efficient operation. It sounds like your system has a lot of crud in it, and that can lead to a blocked pigtail.the pigtail is the curly pipe that feeds the pressuretrol. If that pipe gets plugged up the boiler can be operating at high pressure and that can lead to all sorts of interesting noises.



It's possible that a pipe has settled and does not have the correct slope anymore. If it is single pipe steam the pipes have to slope 1inch in a 10 ft run to assure water will drain back towards the boiler. If the slope is not correct then the steam can meet standing water in the pipe and that can lead to water hammer. See if you can identify what area the noise is coming from and use a level to verify the pipe slope is correct.



Also if it's a single pipe steam system make sure all the radiator valves are fully opened, a partially closed valve can cause banging because the water and steam can't get out of each others way.



Bob

Sleepless_in_Stl

Reply to Bob

Thanks Bob, I did read Dan Holohan's book, that's how desperate I am.  I should have included that my boiler is operating at 1 PSi which I know is what it should be.   I also know about the pipe slope that is needed and from eyeballing it, it looks okay, but the house is 105 years old so I know it has settled some.  Is there a way to check it with more exact measures other than a level?  I will check each radiator valve.  Thanks for trying.

Paul48

Describe

How the water line behaves when the boiler is making steam.You might want to have someone flush the wet return.

Jamie Hall

An eyeball...

just isn't going to do it.  You will need to check every "horizontal" line on your system for the correct pitch for its full length -- not just end to end.  As BobC says, slope in a one pipe steam system is really critical (it is in two pipe, too, but somewhat less so).



Second, do check and make sure that all the radiator valves are fully open.  A partly or fully closed radiator valve can and usually will create a passable Anvil Chorus.



You should not be needing to drain the water from the system that often -- if more than once a season.  That said, you do need to drain the dirty water from the low water cut off/water feed float bowl regularly -- once a week is perhaps a bit often, but if the water is really cruddy, maybe not.  You don't need it to be drinking water clear; it won't be.  But it shouldn't be much worse than iced tea, for instance.  Adding too much water can cause a good deal of corrosion.



Then, of course, there is the elephant in the room: if the system worked fine until last year and then started to clang, what changed?  Because the odds are pretty good that whatever changed is your villain...