Dripping sound in wall

heatinghelp819

We have a one pipe steam heat system in our old home. In one of our interior foyer walls, there is a dripping sound coming from where a pipe goes vertically from the basement main up to supply a radiator on the second floor. That pipe also knocks very loudly when the system comes on, and it sounds like a loud tapping; I strongly believe it is simply a pipe expanding when heating up and rapping against wood in the wall. So basically, it's the tapping sound when the heat is coming on, and then when the heat turns off (rad still hot), the dripping sound starts soon thereafter. I'm not sure if it is the sound of a) condensation coming down the pipe, basically falling vertically from the second floor to where the pipe bends when going to the basement, or b) the pipe (or wood?) contracting again when the steam is no longer coming up from the boiler, or c) a leak.

To complicate matters, we have plaster walls, so not the easiest to open up the wall to see what's happening. Also, the basement ceiling shows some water damage right by where the outlet is for the pipe at issue; however it is also right by (and closer) to the radiator along the first floor interior foyer wall at issue, which had a leak recently, which we repaired, but I had assumed was the source of the water damage.

Any thoughts on how to figure this out?

Fred

Water dripping sounds a lot different from expansion/contraction noises. Are the radiator valves on radiators attached to that riser fully open? If not, it is possible that when the boiler shuts down, enough condensate has built up in one of the radiators to flow (drip) back to the wet return.
Is your boiler pressure set properly? Enough pressure can prevent condensate from getting out of a radiator until the boiler shuts down. What size (diameter) is that riser? What size is the feed attached to each radiator on that riser.

Abracadabra

post a video of the "dripping sound" on youtube and provide link here?

EBEBRATT-Ed

since you see water damage you going to have to open up the wall and find the leak.

JUGHNE

Usually water draining down a vertical pipe that tall will not drip. Rather the water clings to the side of the pipe and even will swirl around the inside surface of the pipe and not drip.

This gives the steam room to go up while the condensate rides the outer rim down.

Does the pipe inside the wall line up with the valve upstairs or is there possibly 2 90 elbows offsetting the radiator with some horizontal pipe involved. If the 90 elbow just inside the wall was dripping down in the wall to the floor plate you might hear that.

IIWM, I would open the basement ceiling at that pipe. Then saw open the floor around that riser under the wall only......this does not intrude on your first floor finish. A 100 dollar bill will buy a pretty good inspection camera from the big box store. It has a 6' flex lens and could confirm if water is indeed inside the wall. That amount of money will not fix (very well) an unnecessary hole in plaster IMO.

That is a tool that will come in handy for more things than one ever imagines until you have it.

Note: with a rubber handle screwdriver, put the tip to the pipe and the handle in your ear. You can hear the condensate draining as it runs down the side of the pipe.

heatinghelp819

On abracadabra's rec, I uploaded a clip of the sound here: https://youtu.be/BCaJfdO1Xk8

Note that when the sound first starts, always pretty soon after the boiler shuts off, the ticking/"dripping" is much faster, almost like milliseconds in a stopwatch. (I can try to get a video of that tomorrow). Then it gradually slows down. Also, as I note above, the same area makes very loud knocking sounds when the heat first comes on, which I have assumed is expansion of the pipes or rattling against wood beams in the wall.

If it was a leak, I'd be losing water from my boiler rand my autofill would kick on pretty often, right? That's not happening right now (after having fixed other issues with my boiler).

Fred

Video won't play

MilanD

Tapping sound is very likely pipe rubbing against the wood inside wall. Have one in the basement of one of my apt buildings, hot water run.

As to dripping sounds, the fact boiler is not making up water may suggest it is inside the pipe, as you suggest, esp. if it's only after heating cycle ends. Condensate may be hanging up somewhere in the rad or horizontal runs before the vertical pipe. Your other posts mentions hissing radiator vents... could be excessive condensate that's not able to return due to steam pressure, now falling back from a almost horizontal and not well pitched radiator. I have radiators on some 18ft risers and have never heard this, but I can see it be the case if rad is big, can take in a lot of steam, if it's almost flat, op pressure is higher, and if swing joints connecting to the vertical riser are pitched just right. Try raising the far side of the rad (vent side) by placing a quarter or two under each leg. This may allow the condensate to return more freely while the boiler is still on.

As to possible leak, plaster can hold to a lot of water before starting to show you paint bubbling and discoloration/staining. I've seen a corroded kitchen sink drain spill into a wall cavity and plaster and lathbceiling for months before it showed up as a leak (based on what the pipe looked like when I opened up the wall to repair it). And I also had a radiator drip that took some long loong time before a 8x8 ft chunk of plaster finally fell down. It being on an outside wall suggested I had issues with box gutters leaking, which I had replaced, and it turned out it was radiator swing joint all along.

So, anything's possible. Could be a leak, could be a rad that needs to be pitched back towards the valve.

Pitch the radiator first, and 3ft flex camera suggested earler is a fine tool too if pitching the rad doesn't eliminate the dripping sound. With flex cam you need only a few holes, easily patched, to inspect a pipe inside a wall for leaks. I've done that too.

Best of luck!

Abracadabra

Video is set to private. You need to set it to public for anyone to view.

heatinghelp819

https://m.youtube.com/watch?v=BCaJfdO1Xk8

Fixed privacy issue, so it should play now.

Weirdly, I just tried knocking on the wall near where the noise was coming from, and it stopped for awhile. So could it be the wall contracting when the heat turns off? It is attached (perpendicular) to an outside wall.

heatinghelp819

Actually it's right at the junction of the interior and exterior wall, so basically in the exterior wall...

Abracadabra

sounds like expansion noise to me

MilanD

Clicking is expansion noise.

Is the other "shhhhh" sound just background noise or a part of the noise inside wall?

I'm hearing "shhhh" like noise on my phone too.

heatinghelp819

@MilanD It's background noise. (White noise machine) Good ear! I definitely can't distinguish between a clicking and dripping sound... lol

I can post a video of the quicker sound later if necessary, but it's source is the same I think. I did end up getting an inspection camera, though sounds like the verdict is expansion noise. If so, is it noise from the pipe expanding or the wall expanding? is there any way to fix either? Spray foam insulation?

MilanD

Is the hum j> @heatinghelp819 said:
> @MilanD It's background noise. (White noise machine) Good ear! I definitely can't distinguish between a clicking and dripping sound... lol
>
> I can post a video of the quicker sound later if necessary, but it's source is the same I think. I did end up getting an inspection camera, though sounds like the verdict is expansion noise. If so, is it noise from the pipe expanding or the wall expanding? is there any way to fix either? Spray foam insulation?

Pipe expanding and rubbing against some structural or other member in the wall cavity.

You'd need to open wall and find where it's rubbing, then add something in between the 2 surfaces, like a cut out piece of soda bottle plastic, or plastic milk bottle plastic...

The other streaming water noise you mentioned, check rad for the pitch... I'd suppose it can use being pitched back towards the valve a smig.

heatinghelp819

@MilanD streaming water noise? No streaming water noise here...

Fred

I think it's just expansion noise, especially next to a cold outside wall.

MilanD

> @heatinghelp819 said:
> @MilanD streaming water noise? No streaming water noise here...

Sorry, meant dripping water from your earlier comment. My bad.

heatinghelp819

@MilanD it's all the same noise, as shown in the video clip. I thought it sounded like dripping.

Thanks all!

HeshamA

I have the exact same noise coming from the ceiling from the unit above me. I expect when they turn on their baseboard heater. Is this something that can be fixed by bleeding the heater ?