Troubleshooting a noisy radiator

mattm

Hi all,
I've got a one pipe steam radiator system, such that I have 6 radiators on the third floor of an old Boston-area condo. 3 of the radiators are virtually silent, two are OK, and the last... well, the last makes every noise a radiator can make. Lucky me, the noisy radiator is in my bedroom.

The issue: this radiator makes water hammer noises, it makes gurgling noises, and it makes low-volume hammer noises (that's the best way to describe it). We have run through a few obvious steps (including calling radiator/plumber guy).

The situation: the first floor removed their radiators and switched to a hot air system as part of a major renovation. The second and third floors are stuck with steam. The second floor seems indifferent to radiator noises, although I have no idea how loud theirs are.

Remedial (failed) steps:
1. Open the radiator valve fully - no effect.
2. Change the pitch of the radiator - this did absolutely nothing to the sounds.
3. Replace the air vent - also did nothing to the sounds
4. Added a ball shut-off valve between the air vent and the radiator. This room gets hot and we don't really need it on at night. The idea was - prevent steam from escaping, no more steam gets in, no more noise! This also did not work, and despite no air venting through the air vent, the radiator still makes the same noises, AND still gets hot. This confuses me.
5. The radiator guy told me the next step would be to cut into the floor, which I'd rather avoid if possible!

Does any one have any ideas? Anything I can do, or ask someone to look into?
All the best,
Matthew

Fred

First off, you are not "Stuck" with steam. You are the lucky ones! Who likes dusty, drafty hot air?
On a one pipe system, the supply valve needs to fully open. Leaving it partially closed in hopes of reducing the amount of steam that fills the radiator only causes water to build up in the radiator and makes things even more noisy. To stop steam from entering the radiator, turn the radiator vent upside down. That should close the valve and prevent air from escaping so that steam can not enter.
Are you sure the noise is actually in the radiator or is it possibly in the piping below the radiator? Is the radiator actually pitched towards a fully open supply valve so that water can drain out? If it could be noise radiating from the supply pipe, it is possible a horizontal pipe under the flooring has lost its pitch. Try to raise the radiator, on the supply pipe side and put a shim or a couple quarters under the legs and then re-pitch the far end of the radiator towards the supply pipe. Raising the radiator a little may give the piping enough pitch to allow water to run back to the boiler.

JUGHNE

Sometimes there is a horizontal run out pipe under the floor that has sagged towards the radiator. This would hold some condensate water that the steam could hit and cause the hammer.

You might try to raise the valve end of the rad and then raise the vent end a little more. Propping up the valve end may raise the run out pipe enough to drain the condensate back to the main.
You still have to have the rad draining towards the valve though.

BobC

Old houses settle and sag and Boston has some very old houses. I had one problem radiator and I fixed it by shimming the valve end up 1/2" and the air vent end up 3/4" - no more gurgling.

Bob

mattm

Thanks for the helpful comments!

I seem to have reduced the water hammer, but am left with a fairly loud constant rattling noise whenever the system is turned on. I can't tell where the noise is coming from. Using a flexible camera I have about 4 - 6 ft of horizontal pipe leading to this radiator under the floor.

I managed to raise both ends of the radiator by about 1/2 inch. There is a cupboard door next to the radiator and from looking at the door frame, it looks like I have about 1 inch of sag in the middle of the house (1910 era), so I'm thinking I need to bring it up a little higher. The pitch of the radiator itself is correct going back to the valve.

- My back can't take much more shimming, would it be a terrible idea to raise it with a jack instead?
- I've attached a photo to show how the air vent is shut-off. Even when it is shut-off, I'm still getting the noise - how is that possible if no steam is entering the radiator? Could I be hearing banging/rattling from a radiator on a different floor? Does this mean I have a leak somewhere where air is escaping? The radiator valve is always open, only the airvent is closed.

KC_Jones

If you could post a video so we could hear the rattling that could help a lot.

Fred

Do you have any idea what pressure the boiler is running at during a typical heating cycle? If you have access to the boiler room, look at the Pressuretrol and see what the scale on the front is set at and, if you can, take the screw out of the lower front center of the pressuretol off, take the cover off and see what number is on the white wheel, facing out. It is possible the pressure is either set high or the pigtail (curled pipe) under the pressuretrol is clogged causing the pressure to be much higher than it should be. It is very possible the rattle/gurgle is coming from the supply pipe feeding that radiator and just echos into that radiator. Noises are sometimes hard to pinpoint.

BobC

I use a 2X4 and a block to raise radiators, it saves a lit of back pain.

Bob

mattm

Thanks everyone, good comments. I think I am making progress on this...

@KC_Jones, good thought! I've got a youtube link with audio of the rattling noise.
https://www.youtube.com/watch?v=_hKJkd9M84Q&feature=youtu.be

I haven't tried the pigtail yet - the water was dirty recently, but as you can see from the photo is now pretty clean, the boiler being recently serviced. As for the pressure, what I think is the pressuretrol, the grey box in the honeywell photo is set all the way down. The pressure gauge from 0 to 5 only has 4 tick marks, so each tick is 1.25 I guess. At it's 'resting' state when no steam is being actively generated, it is at 1.25 PSI. When steam is being generated, its a bit higher, probably around 3.75, so a pressure differential is around 2 PSI. If it is high pressure, why would only one radiator be affected?

I had a couple questions about this. The noise in the recording is with the airvent shut, and the radiator valve fully open - it does feel a little wet (as in leak) even when the valve is open and the vent is closed. The pipe leading out of the floor to the valve is hot, and the radiator is cool (although eventually gets warm). Do you think the radiator valve needs changing? Is there liable to be a steam trap on the main line of a one pipe system?

Fred

Yes, that's the Pressuretrol. The pigtail under it doesn't look like its been off and/or cleaned in years. It is very possibly clogged and the Pressuretrol probably can't even see the system pressure. Definitely needs to be taken off and cleaned. There is a white wheel inside that Pressuretrol that you need to check too. The scale on the front is set correctly but the white wheel should also be set to "1" facing the front of the Pressuretrol. The Cut-in will then be .5 PSI with a differential of 1 PSI making the cut-out a total of about 1.5 PSI. The current pressure of 3.75 PSI is way too high (if the gauge is accurate, which it may not be but set the Pressuretrol correctly)
The noise I hear really sounds like a broken disc inside the supply valve. You probably need to get someone in there to take the bonnet off of that valve and take a look inside. That would explain why it is still noisy even with the vent closed. A broken disk will flop around on pressure in the pipe up to that valve.

KC_Jones

My thought, the valve is broken. Sounds like the plug is rattling on the seat. Sounds almost exactly like one I had "closed" for a while. Or it's something else that sounds similar?

As far as the rad heating with the vent closed, most likely the pressure. It can compress the air and still get some steam in there. Given enough time it will start to heat up.

JUGHNE

BobC's suggestion for the 2x4 & block is what I was about to post. Amazing what levers can move, some have claimed even the moon.

Is the clicking noise loudest at the boiler or your radiator?
As Fred said it sounds likes like a rattling disk of a valve or perhaps a check valve if you had one on the system at the boiler.
One pipe rad valves are just about worthless. They have to shut off 100% or be open completely. Most old ones will not close completely. You could open the valve with the system off and cool, look for the disc on the bottom of the stem and there should be a large rubber type washer on the disk held in place perhaps with a screw in the middle. If the disk or washer is loose and lying on the inlet of the valve it would rattle. Just remove any loose pieces and put it back together with the valve open.

Your control valve on the air vent may be too long horizontally and not allowing water to escape from the vent. You could 90 elbow up to your ball valve and install the vent to allow it to drain. Even with that hole plugged or valve off you will get some steam into the rad as the steam pressure compress's the air in the rad. Your rad may collect water because the vent is closed and after a cycle of heating you could check by opening the ball valve to allow air into the rad allowing any condensate water to drain out. (think of the finger over the end of a straw that you pull out of the glass of water, the water stays in the end of the straw).
FWIW

mattm

Phew, so this weekend I was able to act on your advice.

- The pigtail is not clogged and the pressure is set to the lowest setting.
- We replaced the radiator supply valve.
- I tried to raise the radiator a little more, so as to raise the horizontal pipe below, but I'm hitting the limit of how high it goes.

When I listen to the noise, it certainly sounds as though it is originating in the room of the radiator, although I can't pin it down for sure. The rattling noise has continued, identical to the video, for the entire duration of the radiator coming on - which is torture at night time (this is my bedroom).

My next step is to poke a hole somewhere so I can scope out under the floor with a flexible camera and see where the pipes go. I'm hoping that someone might have some insights though.

Fred

Did you actually replace the supply valve or just the Vent? The supply valve is on the opposite end of the radiator with the knob on it to turn the steam on and off. If you actually replaced the supply valve, that would entail replacing the matching spud on the radiator also.
I still believe it is a broken disc in the supply valve but if you actually replaced that valve, I don't know. If you just replaced the vent, take the radiator loose at the supply valve union and look inside the valve for a loose or broken disc. You can also take the bonnet off of that valve and turn the valve stem completely out of the valve body to inspect.

mattm

Hi @Fred,
Thanks for the reply! The vent replacement was my first step a few weeks ago. This weekend I had the supply valve, and spud, to the radiator replaced - so it has a new valve on it.

I kept the old valve, and the disc is intact, although I'm planning on taking it apart regardless! I was pretty hopeful about the valve, as the rattling is constant under pressure, but no such luck.

I guess the last thing I can do is try and measure, then fix, the pitch on the horizontal run - a nightmare since I have neighbors below me, and would have to tear up my floor.

I should also add that there was no water in the elbow immediately under the valve. There was a small amount of water, as you would expect, in the radiator in the depression below the inlet.

Fred

You have neighbors under you? Do they have a radiator on that same feed? If so, it could be from their radiator/valve. It's amazing how sound radiates through piping. It just does not sound like the kind of banging or gurgling one expects to hear from a pipe that's pitched incorrectly.

mattm

Hi @Fred,
I'm on the third floor, of a three unit building. The second floor has the same layout that I do. I *assume* that their radiator (15 odd feet below me) would be on the same feed as mine, although I can't be certain.

That is exactly the expertise I am here for :-) What type of noise would I expect from a wrongly pitched horizontal run? The plumber/steam guy who replaced the valve did seem to it was the horizontal pipe run, but I believe I have raised the radiator high enough to compensate.

So if you are correct, and it is my neighbors valve, that poses a problem for me, as they may not want to replace, or fix, their valve! For noise traveling like that, would it be effective to clamp the pipe with some rubber or something to quash the noise?

Fred

An improperly pitched pipe, holding water will typically cause a sound almost like someone hitting the pipe with a hammer or it may sound like gurgling, like water boiling inside the pipe. If you had the valve replaced, I'm now wondering if the pipe under the floor or the vertical pipe that comes up to your radiator might be vibrating and tapping against another pipe in the wall or under the floor. Have you tried wrapping the pipe under the supply valve with a towel (so as to not burn yourself) and holding that pipe when it rattles and see if it stops? Might also be a good idea to ask the neighbor below you if they also hear the noise and see what they say.

mattm

Those will be the next steps, they have mentioned that the equivalent radiator is "noisy," but I have no idea what type of noise - I'll try this tonight! Thank you.

Abracadabra

You should be able to remove the bonnet and check the disc to see if it's loose. Brass on brass should come apart fairly easily. If it's loose and it's suspect, use a sawzall to cut the stem right above the disc. If it stops, you've found your loose disc.

mattm

How exactly does the bonnet come off? Does it have to be wrapped with Teflon when putting it back? I'm familiar with vacuum valves but not steam or water. It is likely an old crane valve.

JUGHNE

First of course with the system off and cool and no chance for it to start while you take this apart.
For any valve, I always try to have the stem set halfway open, this prevents the stem/disc/washer from being jammed as you unscrew the bonnet. Usually remove the handle so the bonnet would slip over the stem , (not always necessary, it can stay together usually). I would use 2 pipe wrenches, one on the bonnet and another on the valve body, (even applied backwards if necessary).
The stem and disc/washer may then just unscrew out of the body. Some are more complicated than that, but this might work for you.
Going back together with brass on brass usually requires no dope or tape. I do use a wipe of "Slicktite" pipe dope for fine threads such as these. It is a very fine Teflon pipe dope/paste that works mainly as a lubricate. FWIW

Fred

You had a new valve installed this past weekend and that did not fix the problem. As a matter of fact, you said the old disc was in place and not broken. That's issue can be ruled out. The noise is coming from somewhere else.

mattm

@Fred, absolutely! In fact, I was thinking of my neighbors valve below me. I did carefully look at the valve that was replaced - it is a Crane steam valve. It did rattle a little if I shook it, but not to the extent of the noise. When you say that the disc is broken, would I expect it to be cracked, or completely broken in half and bouncing around in there? Would there be any other symptoms of the break, such as leaks?

Fred

If it's broken, there will either be a piece missing and rattling around when the steam pushes through or the entire disc could have come loose from the stem and be bouncing around.
They will rattle a bit if you shake them because that disc pivots on the stem a little but when mounted and fully open they won't.

mattm

@Fred - I wanted to complement and thank you for your advice! To update on my situation, I had a constant rattling noise that I posted in a youtube clip. We underwent a number of interventions on our radiator and valves to no effect. @Fred suggested that we replace the supply valve on our neighbors radiator a floor below us.

After a bit of a wait, this work was completed last week and has completely eliminated the rattling. So well done to @Fred and thank you to everyone who weighed in! It makes a big difference noise wise! I've noticed a little more steam hammer after the valve was replaced, but at least it only hammers a couple times when it turns on and then goes away instead of the rattling which was pure torture.

This has been very educational.

Fred

@mattm , I'm glad you have some relief and thank you for following up and letting us know how things worked out. Sometimes we never hear back. That hammer you now hear may well be a pipe or radiator out of pitch when they replaced the valve. That too can be corrected fairly easily by making sure that radiator is still pitched towards the supply pipe. If it is, then raise both ends of the radiator up a bit with some shims under each leg and then re-pitch the radiator towards the supply pipe. What that will do is raise the horizontal supply pipe under the floor and give it a little pitch. Best of luck to you!