2 clanking rads—but pitch and pressures seem okay

gilead1234

With ever-increasing fantasies of tearing out the steam system and replacing it with forced hot air, I figured it was time again to consult the Heating Help community again, to help me avoid that route.

The issue, as it's been in the five Boston winters since I've lived in this house, is clanking from two radiators, which starts toward the middle/end of a heating cycle and lasts maybe 5 or at most 10 minutes. Until now, It's been frustrating. But with a sleeping infant now in the house, the loud noises are downright petrifying.

[edit: I know it's hard to tell the exact source, but it kind of seems as if the clanking is coming from the radiators themselves. Also, they clanks are generally accompanied by a constant, gentle waterfall-type sound, which again seems to be coming from the radiators themselves.]

I'm at a loss about what to do—or who to contact to rid us of the problem—because the radiators are all pitched in the right direction, the pressuretrol is trying to keep the pressure as low as it can*, the dry returns are well-vented (with two big mouths, one for each pipe leaving the boiler) and the air vents in question are set to vent slowly — around 3 or 4ish on a vent-rite.

* Okay, I just double-checked the pressuretrol settings and… somehow both "main" and "diff" were set to around 1. I swear last time I looked it was 1.5 and 1. At any rate, the radiators have all been heating up. I've now reset it to 1.5 and 1.

I've most recently contacted a large heating company here, who sent over a friendly-enough younger tech who didn't recognize the flaws in my near-boiler piping, stared at me blankly when I asked about vaporstats, and left saying the problem is probably under the floorboards, with a poorly pitched pipe.

That's possible for the upstairs clanking radiator, where one can't see the piping. But the downstairs clanker is just above the exposed piping in the basement, which seem to tilt properly back toward the boiler.

Is there a way to silence the system without tearing up my floors and walls? (Worse yet would be tearing them up and still not succeeding to silence it!) I'd love to put this in a professional's hands. But don't want to again spend money just to have a non-steam-expert say that the answer is under the floorboard. (In a past winter I had @New England SteamWorks come out here before to install new mains, but they weren't able to stick around to diagnose the cause of the clanking.)

Many thanks again for any thoughts or suggestions. Images follow. (And for unrelated details on my heat system, see also this wall post, though I've given up on silencing the baseboards for now because I've gotten used to their percussion.)

Jamie Hall

You've had @New England SteamWorks out? Have them again. That's by far your best move.

gilead1234

@Youngplumber Do you mean the hot water that's being pumped to the hot-water zone (as opposed to the hot water tank)? I don't know any reason they did it that way — but I do know it's a problem: https://forum.heatinghelp.com/discussion/164196/hot-water-zone-added-to-steam-system-is-a-total-bust. But like I said, I can live with the annoying noises from my hot water zone. The clanking radiators, including one in a bedroom, are the bigger problem.

ethicalpaul

> and left saying the problem is probably under the floorboards, with a poorly pitched pipe.

Through knowledge or luck I think he's got a good chance of being right about this one. But we can't see your near boiler piping and that's another possibility.

BobC

Try lifting the whole radiator up on the second floor, this could correct any pitching problems under the second floor. Use a 2x4 to lever it up and slip 1/2 or 3/4" shims under the radiator legs. Also don't trust your eyes, use a level to make sure pitch is correct.

Bob

gilead1234

ethicalpaul said:

> and left saying the problem is probably under the floorboards, with a poorly pitched pipe. Through knowledge or luck I think he's got a good chance of being right about this one. But we can't see your near boiler piping and that's another possibility.

I should have asked you this a year ago, but… what would that mean, practically? Game over--keep waking up from noisy rads, gut rehab, or freeze to death?

ethicalpaul

Here are the three most likely fixes in my opinion:

1. by raising the radiator an inch or so you might get lucky and eliminate or reduce the sag in the pipe if there is one) and the resulting hammer.

2. if that fails, you can open the floor beneath the radiator valve to see and repair any sag. 

3. Worst case (I had this): if the sag is in the basement and difficult to reach you might have to re-run the pipe either in the wall or in my case I reran it against the wall in the room below which ironically was the way the piping originally was