Severe water hammer and where is my main vent?

Ethel_Lynn

Hi all,

I bought a house back in April and have had the fortunate experience of trying to figure out why my steam system sounds like WWIII every time the heat starts up. I've purchased 'We Got Steam Heat' and have been attempting to troubleshoot what plumbers/HVAC companies I've hired can't seem to fix.

Here's what I've had done so far or have done myself:
• All radiator vents have been replaced (some more than once)
• Problematic radiators have been pitched
• The entire system has been flushed more than once
• A cleaning chemical was used after the last flush
• A boiler blow down has been completed about once or twice a month
• The boiler room has been insulated, the rest of the piping in the basement has not, because I live in it and need some of the heat. The insulation did not help with the noise at all.

One company I hired did seem to think that the main vent is somewhere in the ceiling above my boiler and said they'd have to break the ceiling to get to it, but they never came back for the job. This does bring me to my main question though, where is my main vent and what is this weird pipe doing that goes nowhere?! I've attached some images to hopefully get some answers. If the main vent is clogged or missing all together I assume this could be the reason for the water hammer. Another weird quirk I've noticed is that every time I do a blow down the water in the sight glass seems to rise a little. It started at around 1/4-1/2 full and is now about 3/4 from the top, not sure if this is related or not.

Any info you have is greatly appreciated, thanks!

Danny Scully

Alright a few quick answers. The capped pipe is the old equalizer from the original boiler’s header. You currently have 2 headers and 1 equalizer. This should be corrected, resulting in only 1 header and 1 equalizer. Also, when you use terms such as “flushed” and “blow down” it makes me wonder if it was ever actually skimmed. Some more pictures of the boiler would confirm this. Without skimming you can flush and blow down forever without results. Finally, your main vents should be at the end of the steam mains, not necessarily in the boiler room. Follow the piping out to see where it ends. Where exactly are you located?

Fred

You need someone who knows steam to come in there and correct the piping, install main vents, check the pitch of all the piping. As Danny said, that capped pipe is where the old equalizer went down to the old boiler. That old header is most likely pitched down towards that capped pipe, meaning it is holding water that can't go anywhere and that is a source for hammer. Any piping that is pitched the wrong way or has a sag in it will also cause hammer.

Ethel_Lynn

Thanks for the info. I'm comparing my setup to a proper diagram and what your saying makes sense to me. I will provide additional images of the boiler when I get back home. Doesn't skimming usually require a hose hooked up to the top of the boiler? I have never seen them do this, so I'm guessing that it has not been skimmed. I live in Jersey City, NJ and have had a hard time finding someone that is knowledgeable in steam. Any references would be appreciated. I should also note that all of the piping in the basement or 90% of it is exposed and I haven't seen one main vent anywhere.

Jamie Hall

Jersey City? Try @EzzyT or @JohnNY ... there are a couple of others whose names escape me at the moment...

New England SteamWorks

Also @Dave0176 & @Danny Scully

EzzyT

@Ethel_Lynn private message me and hopefully we can set something up

Jamie Hall

Sorry, @Dave0176 and @Danny Scully . You were the others I was thinking of, but couldn't bring your names to my head! I' going to make myself a little map of who works where, in terms of Wall handles!

Danny Scully

That’s ok @Jamie Hall, I’m actually a Long Island guy who’s had the pleasure of working with @EzzyT a few times. While I don’t mind being grouped with these names, I unfortunately don’t service that area.