More detail on one-pipe steam clanking and banging

jch1

Good evening,

I asked a bit ago for some input as to where the source of my radiator noise could be coming from. I've narrowed it down now to two problematic radiators. One essentially never warms up, and I can't open/close the valve at all, and the other barely gets warm at all. The noises I'm hearing ALWAYS happen at the same time every night, which is strange. The best way I could describe the noise is that it sounds like someone is dropping a heavy metal object onto another metal object, and it bounces a couple of times before settling. Could it be that I need new valves for these radiators? Should I just look into getting two replacement rads?

Fred

That sounds like water hammer which means the steam is hitting water somewhere in or near those two radiators. You might try to loosen the packing nut just below the valve handle and see if that allows you to turn the valve. If that doesn't work, take the union lose on the radiator that the valve won't open or close and see if that valve is closed/mostly closed preventing water from getting out of that radiator but still allowing some steam to get in, hitting the pooled water and condensing when it hits that water, also causing the hammer. While you have that union lose, see why that valve won't open or close. One one pipe systems, the valves should always be fully open.
Make sure both radiators have some pitch back towards the supply valve so water can drain. Make sure the radiator run-out, in the basement is pitched towards the main and not the opposite direction. If the banging seems to be under the floor, on the second floor, try raising the entire radiator up a quarter to a half inch, if you can. That will raise any horizontal pipe under the floor enough to give you some pitch on that pipe. Then re-pitch the radiator.

Jamie Hall

I am inclined to ask -- does anything else happen at the nearly the same time? The boiler turning on to recover from a setback? And does the noise never occur at any other time?

Anyway... do those two radiators share a runout or a riser? Because if so, the problem may be in that piping. I don't recall your previous thread -- is this one pipe steam? If it is two pipe, the problem could also be in the return.

If it's one pipe steam, one really wants to make sure that the inlet valves are fully open -- partly open or closed will cause problems. On the one you can't turn, have you tried backing off the packing nut (around the stem where it come out of the valve body) a bit and then trying to turn it? That sometimes helps.

New valves are always an option -- but keep in mind that if you change the valve, you also have to change the spud which screws into the radiator (they are matched) and that is not always quite so simple.

jch1

Sorry, I should have provided more information. All valves are opened all the way (though I can only assume that's the case with the one that won't move in either direction- I have not adjusted it since last year, when I know it was opened). And yes, all radiators are properly angled back towards the valve by way of a couple of shims.

I'm not sure if they share a common riser unfortunately. However, my piping near the boiler is adequately pitched, and I am confident that the piping was done correctly (I've been around the wall for long enough to know what's right and what isn't, plus I had the Steam Whisperer come out to take a look at it a bit ago).

The noise occurs at around 8pm, which seems to be when the boiler turns on these days, but it isn't the result of recovering from a setback, as there isn't one at that time. Basically, I have my system set for 2 degrees colder overnight, and that goes back up in the morning.

Here's an update as I was typing this out. The boiler just fired up, and I hear the usual light taps on the wall leading to the 2nd floor. While those taps are occurring, that's when a huge bang occurred. So yeah, it seems like it may be water somehow trapped, though I'm not sure how to get rid of it since I've raised the two problematic radiators 1/2" on the vent side and 1/4" on the valve side.

I should probably look into having someone replace the valves, yeah? I'm pretty mechanically inclined, but I don't have a spud wrench as of yet, so is this something I could do myself? If so, is there a recommended valve brand? Should I consider going with TRVs?

Fred

Did this problem exist when the Steam Whisperer was out there? I know he would have been able to diagnose the issue. Did he give you any suggestions? Have they been implemented? If I were going to change valves/spuds, I think I'd wait for the weather to break. You just never know what problems you might run into. Getting those spuds out can be a challenge. I wouldn't add TRV's unless those rooms over heat. I doubt they do if the rads aren't heating. You can always add them later, once this problem is resolved. Why add another element to the mix. What kind of vents do you have on those radiators? Are you sure they are working? If enough steam is getting up to the radiator to cause hammer, the only other possibilities is 1) the vents aren't open to let air out or 2) the supply valves aren't fully open or 3) water is pooled, either in those radiators or at a pipe very near the radiator. Have you felt the supply pipe, just below the supply valve? Is that pipe hot?

Ironman

TRVs go on the vent tapping one a one pipe system. They won't help your problem.

Before you replace the valves, I'd follow Fred's advice and see if you can free the valve by loosening the packing nut and turning the handle. You may also try removing the cap nut and taking the valve apart, but..be careful..and have a new one on hand. Getting the old spud out of the rad can be very difficult.

It sounds more like a sagging runout that's pooling water.

jch1

Unfortunately, we weren't able to replicate the banging when his guy was out. I even turned the heat off an hour before he arrived. That's the strange thing. The noise doesn't occur until after 8pm (and it happened again at the time of my last post). He indicated the noises he heard when he was here were normal (it was only the light tapping noise, not the loud clanks)

All of my radiators have Ventrite 1s or the adjustable Hoffman vents. I have one spare ventrite and about 3-4 spare hoffmans that I've put on these two radiators with no luck. I suppose I could try cleaning the vents and then seeing if they work?

On the radiator that gets slightly warm (to the point that I know it has steam in it but it certainly isn't warm enough to actually heat up a room), I closed then opened the valve today. How many turns should it take to open it all the way? I twisted it no fewer than 10 times for it to go from fully closed to fully open. Not sure if that may be helpful information.

I have not felt the supply pipe below the valve. I'll do that next. It seems like my options are 1) clean the vents; 2) replace valves; raise radiators higher. Am I missing anything?

Thank you both for your help!

jch1

Are the valves available at HD reliable, or should I look to a place like SupplyHouse? Preferred brand for standard valves?

Ironman

jch1 said:

Are the valves available at HD reliable, or should I look to a place like SupplyHouse? Preferred brand for standard valves?

Definitely not!

The two models that you have now are usually the most reliable and versatile. Although, I just did a job where all the varivents that I ordered came through branded "Legend Valve". They make a definite "pop" when opening and closing.

MilanD

Fwiw, a few of Hoffman 1A rad vents on our system are 20+ years old. If it's the same quality today, I'd definitely go with them. A few bucks more than the varivents, but seem to last for ever. And can be dialed in.

Supplyhouse.com has them.

As for the banging, try to catch it and post a video of it here (YouTube link). It'll be easier to diagnose. But from what you said, sounds like a water hammer. There is a sag somewhere.

MilanD

As far as noise happening at the same time every evening will most likely have to do with a set of circumstances which create a condition for it... So perhaps, a firing schedule may help figure out why it happens only at night.

Are you home all day to notice if it happens at other times? Is the heating schedule different on the weekends, or during the day?

jch1

@Ironman and @MilanD - I think there may be some confusion here. I know that the brands of vents I am using are legit. Side-note, I'm not talking about the "vari-vents", rather, I'm referring to the Vent-rite Adjustable vents. Completely different brand/product, and many people on this forum are happy with them.

Aside from that confusion, my question wasn't about reliable vents. I'm asking what valve brands are reliable- are the ones available at Home Depot any good? If not, who makes a good product? It looks like SupplyHouse sells "Matco-Norca" - should I just go with theirs?

And last, @Jamie Hall when you mention changing the spud, that comes with the valves available at SH, right? It's not a separate component I have to purchase, is it?

I checked this morning, and the supply lines are both warm below the problem radiators.

MilanD

Ok, here it is: your 2 degree set back clued me to it.

Overnight, your firing is spaced apart more. Whatever water is pooling has time to slowly drain back. Then, it takes the whole day to build back up and start banging. You may have to try lifting up that rad further. It'll be obvious if it's doable when you try with a 4x4 and a long metal breaker bar.

As to non working rad: the fact your riser pipe is warm and the rad is not, points to venting if we assume valve is open. If the valve were closed, that riser pipe would also be cold as no air would be escaping and the pipe woild stay "dead" with no steam coming in.

To remedie this, try slowing down venting to a few other radiators in the house. This radiator not getting hot but pipe below it does, means tstat satisfies before steam makes it's way to the rad. That may be your longest riser and also farther from the boiler than other rads. I'm assuming it heats better in the am after the set back, and not as well during the day on shorter cycles. It may get warm pipe below the rad in the am, but not during the day.

As to valves, I've replaced several and installed several of them with the ones from Supplyhouse.com. Those valves are fine. They come with the spud, so nothing extra to purchase when you buy the valve: it comes with the spud.

Search Supplyhouse site for "spud wrench". They are 10 bucks. If you decide to do all this yourself, just make sure to have a good assortment of large pipe wrenches and get some penetrating oil: kroil or pb blaster to apply to the threads on the current radiator. Let the penetrant work for you, then remove the old spud. You can destroy it with a wrench as it won't matter. You may need a breaker pipe to make the wrench handle longer for a better lever. Matter of fact, if you egg out the old spud, it may make it easier to back it out of the radiator. (Side note: kroil smells a lot better and to me it made a difference when used on rads in rooms, vs basement where you won't necessarily mind the "mechanical" smell of pb blaster, quite pungent and lingering).

BobC

The SupplyHouse valves are decent, not as well made as your originals but those just aren't made any more.

A spud wrench is a separate tool and all to often does nothing but strip out the nubs on the old tailpiece. Then you have to cut the old tailpiece out and that has to done with care.

New valves are shorter than the old valves so you may have to add to the pipe coming out of the floor to mate everything back up. Don't start working on something like this without having everything you need on hand and be prepared to have the heat off for the day - or longer if it's your first go at something like this.

Bob

Fred

Buy the SH valves. They come with the matched spud as a set. I still am not sure you need to replace those valves. Disconnect the radiator at the union and look into the valve. If it is open, just leave it as is. It's not worth replacing unless the body is cracked. When you need to turn the heat off in that room, we always suggest just turning the VENT upside down anyway. That prevents air from escaping the radiator and is a better option that closing the valves.
Back to your issue. If the pipes, just under your valves are only warm, after the boiler has been running for a full cycle, your problem is below that point. Either there is a horizontal pipe under the floor that still isn't pitched enough or your radiator run-out, to the riser that feeds those radiators is pitched the wrong direction or has a sag in it that is holding water. My guess is the pitch, either under the floor or in the horizontal run out. If it were a sag, I would expect the water hammer to be more often. I'm guessing that, for whatever reason, your heating cycles may be timed in such a way (maybe you lower and/or raise the tstat manually during the day or raise it when you get home from work) that it takes a couple heat cycles for enough water to pool in one of those areas to maybe cause the hammer. Up to that time, a smaller pool of water may be lying in one of those pipes to just cause the steam to condense at that location, until it builds up enough to cause a hammer.
It would be great to actually record the noise so we can actually hear it and to see a picture of the horizontal run-outs to those two radiators, in the basement.

jch1

Hi all,

Sorry for the delay in responding - I was traveling for work last week, but I appreciate all the responses. Over the weekend, I lifted essentially all of the radiators between .5-1 inches on both sides, while displacing the vent side higher than the valve side, using a number of washers. While the frequent light tapping/ticking is still present, I'm happy to say that the loud bangs appear to have been completely eliminated! It's been pretty warm in Chicago lately, so I haven't been able to really sit back and listen, but I think that may have solved most, if not all, of my problems.

I'll have to check to see if all of the rads are now heating up, but I think they are. Whether the system is balanced is another question entirely.

Thanks again!

Fred

The light tapping/ticking is most likely the radiators expanding/contracting. Cut some circles/strips of plastic milk carton and put a piece under the feet of the radiators making that noise. That will allow the rads to slide when they expand/contract. Also, check where the supply pipe comes up out of the floor. If the pipe rubs against the flooring, that too will make that noise. Either open the hole in the floor up a bit so there is no rub or shimmy a piece of plastic between the pipe and the area of the floor that rubs. See if that fixes your expansion noises.

marcusjh

I've noticed our bedroom radiator rubs against it's feed hole when heating up now - it's a lot quieter than the banging it used to make before I lifted it up. I've been wondering what to do about that - will the plastic melt? I've seen our vinyl floor in the kitchen get fairly browned from the feed-pipe, so I'm a little weary....

jch1

Unfortunately, the tapping/ticking appears to be coming from a vertical wall in the first floor, and not directly by a radiator. We may have to just deal with that one!

Gsmith

If you use a plastic milk jug to cut the plastic pieces from (#2 HDPE recycling symbol on the jug), it has a melting temperature of 268 degrees F, well above steam temperatures of 212-215 deg F, it may soften a little bit but will not melt.

Fred

Also, the noise coming from the wall is very possibly from the pipe rubbing on the floor/sub floor where it enters the wall in the basement. Check that area out and use the plastic if needed.