Water Hammer Of The Gods

SteaminTed

Hello, Wallites! Cannot tell you how relieved I am to have found my way here. And now: my troubles...

I am the relatively new owner (1+ year) of a lovely old three-story Victorian pile in the eastern Hudson Valley. Newish boiler (15 years old maybe?) sends steam at 1psi into an old array of branches and pipes (60 years old? 80?) fanning out and up to one-pipe radiators (7 on the first floor, 2 on second, 4 on third).

Heating is uneven to say the least, but the most pressing problem is an unbelievably loud, violent and prolonged session of water hammer in the riser taking steam from the basement directly to a third-floor radiator. The risers are behind the wall - actually behind a small pair of corner walls constructed to hide them when the system was put in. And the riser passes - of course - just along my bedroom wall. When the system is warmed up, the hammering is minimal when the boiler runs. But the cooler the system at start-up - as after an overnight of cold temps - the more violent. After a really cold night, the banging will continue for 10 or 15 excruciating minutes.

Being a fairly handy person who likes to solve problems, I had concluded that the water-hits-steam collision was happening in the old and leaky basement feed pipe to the riser, possibly because the condensate return below it was clogged and the water was being forced back into the steam pipe. Since there were two or three pinhole leaks sprouting, I replaced both pipes with new copper in September. But the problem only got worse - probably (I'm really trying to learn) because the steam is flowing better now and the problem wasn't in that pipe after all.

I'm new to the forum, so I'm not sure how to upload videos/audio files of the system and its sounds, but will gladly do so. I would gladly submit to the wisdom of a Steam Wizard, but I have not found anyone in my area (Westchester) who seems to embrace the mystery and magic of steam in crazy old homes the way the folks who built and visit this site do. I get a lot of shrugs and cheerful warnings that fixing it will cost more than building a new house. Maybe that's true, but I hope not. And what I see in other postings here gives me real hope.

Humbly, SteaminTed

mikeg2015

Main header is probably not pitched adequately due to settling. Condensate is pooling and then flashing to steam as new steam reaches it.

Jamie Hall

As @mikeg2015 suggests, the problem is almost certainly an improperly pitched pipe -- with, quite possibly, a place where condensate is supposed to drain away to a wet return and doesn't, either because the return in question is plugged up -- or perhaps even missing.

Steam is not a very mysterious thing, although it can be slightly puzzling at first. There are two books, available in the store on this site or on Amazon, which can be very helpful: "We Got Steam Heat" and "The Lost Art of Steam Heating". The former is sort of a general guide; the latter is more technical, and is directed more at the professional or the enthusiastic amateur. Either or both would be worth getting and reading.

That said, the thing to do while you are waiting for one or both is to wander down to the basement and take a look at all the steam piping and returns and just think. Think to yourself "if I were water and I were in this pipe, where would I go to get back to the boiler"? If I were air, how would I get out of the way of the steam? If I were steam, how would I get to the radiator? Look at all the pipes, and check to see that they are straight (no sags -- common enough in older houses!) and that they pitch so that the water can drain away. Does some of the water drain into a low pipe going back to the boiler -- a "wet return"? Might that be plugged up or slow to drain?

And come back here with questions!

If you do get to the point that you want professional help, there are some very good steam men who will go to Westchester County.

SteaminTed

Thanks for such swift and helpful input, guys... I think it IS a "wet" return system (pic attached). Certainly the condensate returns all seem to lead to a cluster hugging the boiler about twelve inches off the ground. Interestingly, one of the connections - a four-inch nipple running parallel to the ground - JUST starting rotting out about 2 days ago. I've got it plugged with Waterweld (also pic) until my plumber can get in and fix it (or until I can summon up the nerve to do it), but the real lesson might be that the rot does suggest that there is real degradation in the wet return, does it not?

lostinheating

Dependi g how handy you are that pipe is fairly easy to replace. Especially having a union near by. I would replace from the T going right. Undo the union on right unscrew nipple out of T. Or you can leave attached for now cut small section out of nipple and take nipple out. Then undo union and repipe from (looks to me a trap but I know I'm wrong) going left

Jamie Hall

The good news is that repiping is going to be a bit of a time consumer -- but not that bad. The bad news is that if one piece of a wet return has decided to leak, the odds are that the whole thing is going to go in the near future. I'd redo all the wet return piping...

SteaminTed

Great to have this input, believe me! Jamie, do you think this corrosion in the wet return might be contributing, somehow, to the water backup that's leading to the hammering?

Jamie Hall

Wouldn't be a bit surprised. Corrosion... and probably at least partly as a result pretty gunked up pipes.

When you do replace them -- do yourself a favour and spend a few extra bucks and put in Ts or crosses where you can, so you can open the thing up and flush it out.

Mike Cascio

That looks like an old check valve on the right, wonder if its stuck...

SteaminTed

Ok, getting ready to replace that nipple. In the meantime, two more items: first, below is a link to an audio file of this morning's water-hammer, which lasted 75 minutes. The recording does not do justice to the volume of this thing; you can also feel the tremors across the room. Second, I've been catching up on Dan H.'s writings and lectures (I have ordered We Got Steam Heat) and was really struck by his story about the room atop the Empire State Building which receives steam and heat within seconds of the boiler going on. My house is 103 stories shorter than the ESB, and it takes 20-30 minutes for the third-floor radiators to get warm. I'm trying to make sure the valves on the radiators are properly venting the air to get out of the way of the steam, but other than that...??