Yet Another Non-Working Radiator Question

mblucas

Hi--I posted here years ago about a non-working radiator in our master bedroom, which still doesn't work despite many qualified people looking at it. For background, the rad is on the 2nd floor of a 1920s house, it's the longest run in the system, and the radiator is a wide (4+ feet) and low convector. Now we're doing a remodel, and the part of the line in the garage has been re-piped. When the plumber removed the old pipe, lots of rusty water came out (he said that water should be going back to the boiler). With new pipes and that rusty water out, I thought the rad might get hot, but it doesn't.

Here's the question: as an experiment, I removed the vent while the system was running (all radiators hot except that one). I wanted to see if air was getting through. Instead, cold water shot out of the vent. It looked clean (not rusty, etc.). Anyone know what that means? I thought maybe it means that the radiator is full of water, but it doesn't seem like it would be so clean if that's the case.

More backstory: the most compelling diagnosis I got was from a plumber who thought the pipes settled with the house. He removed and tried to lift the radiator, but couldn't, and said it's probably stuck on joist. We've assumed that fixing the problem would mean tearing out the walls, and so we haven't done anything to fix it. Of course, we'd love to get it working without tearing the house apart.

Thanks.

ethicalpaul

It could be a couple things but the first thing that comes to my mind is when your plumber took apart the old pipes and found water. Did he address that problem? The problem was a "sag" or incorrect slope in that supply line that causes water to pool there. It will act like a trap and allow no steam to pass (or maybe a little bit might get by depending).

Did he address the pipe sag or slope at that time? There may be other areas, as your other plumber said, due to settling (or bad initial installation, who knows?)

Note: Forget thinking about "the radiator being full of water" as the problem. That is the symptom. You can empty the radiator every day and the problem will remain.

PS: Your experiment to remove the vent on that radiator was a very good experiment.

Jamie Hall

Let's see. You got water from the pipe when you repiped (your plumber was quite right -- that water should have been in the boiler) and when you remove the vent you get water.

Somewhere between the takeoff from the steam main and that radiator there is a real trap for water. It may just be that the house has settled enough; it may be some quirky bit of pipe -- but until you find it and fix it, I don't think you'll get much heat there.

Hap_Hazzard

ICYMI
https://forum.heatinghelp.com/discussion/160290/stumped-re-non-functioning-radiator

mblucas

Thanks all. Just one other bit of information. When the plumber had the line disconnected, I ran a snake up through the pipe, and it went easily to the valve to the radiator upstairs. That seemed to tell me that there are no significant bends/elbows in the system--so it just doesn't seem like there's a place for water to pool. The plumber is re-piping again today (for different reasons related to remodel), and I'm pretty sure he'll get it pitched correctly, so I'll have another look. The upshot is that it seemed like all the water poured out when he disconnected the line, and it's hard to imagine where else it could be pooled (we can't see behind the walls, of course, but it just seems like the pipe goes straight up and doesn't have any horizontal runs).

KC_Jones

Have you corrected the main venting yet? I noticed in the other thread it looks like you don't have enough. Need the length and size of the mains to determine an appropriate amount. They system can not be properly balanced until the main venting is correct.

The pooling appears to be the primary problem, but the venting isn't helping.

ethicalpaul

mblucas said:

Thanks all. Just one other bit of information. When the plumber had the line disconnected, I ran a snake up through the pipe, and it went easily to the valve to the radiator upstairs. That seemed to tell me that there are no significant bends/elbows in the system--so it just doesn't seem like there's a place for water to pool. The plumber is re-piping again today (for different reasons related to remodel), and I'm pretty sure he'll get it pitched correctly, so I'll have another look. The upshot is that it seemed like all the water poured out when he disconnected the line, and it's hard to imagine where else it could be pooled (we can't see behind the walls, of course, but it just seems like the pipe goes straight up and doesn't have any horizontal runs).

I'm not sure you're quite getting it.

The problem isn't sharp bends or turns. The problem is an area of horizontal piping where there is a "valley". This can be very gentle. Water will go to the lowest area it can find, and in your case, it seems to be doing so.

> The upshot is that it seemed like all the water poured out when he disconnected the line, and it's hard to imagine where else it could be pooled

It seems like you think that once you pour the water out, the problem is solved. But when the system is steaming, it is delivering water to all parts of the system (in the form of steam) and that steam will condense and produce gallons and gallons of water that can re-collect in the mis-pitched areas.

And these mis-pitched areas MUST exist counter to your statement that all the pipe is vertical, or else where did the water come from when he disconnected the pipes and found water in there? If the pitches were correct, all the water would have drained out before he disconnected the pipe.

Or am I misunderstanding you?

mattmia2

I'm thinking the piping between the boiler and the riser to the radiator has a low point that is collecting water somewhere. Can you show pictures of this piping/follow it back to the boiler?

Jamie Hall

mattmia2 said:

I'm thinking the piping between the boiler and the riser to the radiator has a low point that is collecting water somewhere. Can you show pictures of this piping/follow it back to the boiler?

Agreed. And it might be just a serious sag -- it doesn't have to be an actual bend or fitting of somesuch.

mblucas

Thanks for the responses. Ethicalpaul: Maybe I'm still totally missing something, my idea was that it would have been difficult to snake around an elbow, and that I was able to go straight up to the rad. If there's a low point where water is pooling, I assume it has to be on a horizontal pipe, correct?

If I'm following the theory in the other comments, it's possible that there is an additional low point from the boiler to the newly replaced pipes (where the rusty water came out). That would mean that the water is pooling somewhere in a mispitched pipe in the closer-to-the-boiler piping. I probably still don't understand how that leads to clean water shooting out of the radiator vent upstairs.

Also: we used to get severe water hammers in that line, but so far nothing. Just not getting hot.

ethicalpaul

OK I think I understand what you meant about the fittings and the ease of snaking. Thank you.

Yes the water is pooling on a horizontal section I think.

There is often a short horizontal section in the floor under the radiator, and sometimes one right where the riser comes off the main.

check out this thread where I had this problem: https://forum.heatinghelp.com/discussion/167233/fixing-pitch-issues-in-old-house/

(and am finally addressing in the "Saturday afternoon repipe" thread)

mblucas

Mattmia: if you follow the link above (posted by hap_hazzard), you'll pull up lots of pictures to the system.

Jamie Hall

mblucas said:

Thanks for the responses. Ethicalpaul: Maybe I'm still totally missing something, my idea was that it would have been difficult to snake around an elbow, and that I was able to go straight up to the rad. If there's a low point where water is pooling, I assume it has to be on a horizontal pipe, correct?

If I'm following the theory in the other comments, it's possible that there is an additional low point from the boiler to the newly replaced pipes (where the rusty water came out). That would mean that the water is pooling somewhere in a mispitched pipe in the closer-to-the-boiler piping. I probably still don't understand how that leads to clean water shooting out of the radiator vent upstairs.

Also: we used to get severe water hammers in that line, but so far nothing. Just not getting hot.

Oh wow. You used to get water hammers in that line? But now no heat? Somewhere there is a stretch of near horizontal pipe which is seriously pitched the wrong way and is collecting water.

As to why that might lead to clean water shooting out? Think. You have a pool of water in that length of pipe. So long as the radiator vent is closed the steam pushing on one end of the pool can't get very far as the water and air are trapped in the pipe. You take the vent off, and whoosh.

mblucas

Some new info: set system to 73 to keep it running, took off vent, heard all kind of gurgling and water hammers from inside the radiator, and possibly just below the floor, and then a torrent of *black* water (not clean this time) comes gushing out of the radiator. With a couple of minutes, the radiator gets hot (first time in 4.5 years). I try to let as much water come out as possible before I screw in the vent to avoid burns and/or flood. Water hammers for the time being seem diminished. Drips of black water are still coming out of the top of the vent.

I'm curious about the comment that there's often a horizontal stretch of pipe just below the floor. If so, seems like that could be the problem. Not convinced that this is now suddenly solved (though I've had the vent off before and never had water ejected from it, so that's new).

mattmia2

Through all of this did you try blowing through the cold vent to make sure it was open and not plugged or at least swap it with a known working vent?

mblucas

I've tried probably a half dozen vents (and the plumbers who've checked the system always swap them out). I decided to try now because the visible basement piping on this line was all redone with the remodel. It seems like the current vent is now working, as it's burbling air and water.

Another thing: it sounded like something chunky was banging around in the system (inside radiator or in piping just underneath floor). I'm almost wondering if there's been an obstruction inside the rad that has now been dislodged. There was clearly a lot of rusty sludge in the line that came out when it was disconnected.

JakeCK

> @mblucas said:
> Another thing: it sounded like something chunky was banging around in the system (inside radiator or in piping just underneath floor). I'm almost wondering if there's been an obstruction inside the rad that has now been dislodged. There was clearly a lot of rusty sludge in the line that came out when it was disconnected.

Moving water is a powerful force, heated water even more so. any noises is probably just from that.

ethicalpaul

The valve at the input of the radiator can make some noise and can even be broken inside. The part that seals can rust off and be lying in the bottom of the valve, which can also prevent condensate from exiting the radiator.

But also, very small occurrences of water hammer can make that kind of noise I think.

> Not convinced that this is now suddenly solved

I agree completely. The root problem is not the water. The water is a symptom.

mattmia2

Did you see the snake actually come out of the riser, or is it possible that it stopped at a lateral just below the radiator in the floor? It sounds a lot like there may be a horizontal pipe in the floor just below the radiator that is pitched toward the radiator and the noises you were hearing were the steam interacting with that pocket of water.(the broken valve is a good thing to look at too).

You might be able to see what is happening under the floor with a flashlight if you pull the escutcheon back.

mblucas

Thanks to you both. Update: Rad not getting hot. If I remove the vent, I hear gurgling water, and I think I’d have a repeat of earlier (geyser of black water, rad then getting hot). I think vent maybe isn’t working because of the water/sludge pushed through it earlier. So lots of water in system that isn’t going back to boiler.

Matt: good question. Wife was listening upstairs and thought she heard snake in valve, but maybe she heard it in pipe under floor. Unfortunately, too late to try again with pipe no longer open. No escutcheon—can’t really see below.

mattmia2

You could even take the valve off or maybe even just take the stem out and look down in the pipe and see if you can tell where it goes and if it is full of water.

You could also try slowly raising the radiator and see if that gets stuff flowing right again.

SeanBeans

Is the valve in working order?

mblucas

I brought someone in a couple years ago—a steam expert recommended on this site—and he removed the radiator and tried to raise it. It was stuck—he guessed on a joist somewhere in the wall. The valve is fairly new. I do recall that this same steam guy said that it was installed upside down, but I don’t believe that was thought to be a major problem. The coupling is below the floor, so not easy to reverse.

Kind of back where I started: most likely dealing with a sagging pipe in an inaccessible location.

mattmia2

Maybe you could remove a baseboard or other trim and see what is going on. If you can figure out where you need to get to, busting a small hole in lath and plaster and patching it with wire lath and plaster isn't that bad.

ethicalpaul

> I think vent maybe isn’t working because of the water/sludge pushed through it earlier. So lots of water in system that isn’t going back to boiler.

Just for clarity, the vent can’t cause water to stay in the radiator.

It can fail “open” where steam will leak out even when hot.

Or it can fail “closed” which won’t let air out during the call for heat resulting in a cold radiator.

I can’t picture your valve description. If you are open to posting a picture that’d be appreciated. I’m very sympathetic to your situation as I had that very similar one described in the thread I pasted above

mblucas

Ethical: if you click on the link above in hap-hazzard’s post and then scroll down a bit, there’s a pic of the radiator where you can see the valve. What ultimately was the fix for you?

Crazy water hammers are back, so status quo is fully restored (despite new piping in basement). It definitely sounds like there’s a chunk of metal moving around inside the rad or just below the floor. I know the rad was removed and the valve replaced for restoration work before I moved into the house—wouldn’t surprise me if they dropped a bolt or some other hardware in the system.

mattmia2

What I am thinking is if there is a lateral below the radiator in the floor that is holding water, if you take the stem out of the valve you should be able to look down through the seat with a flashlight and see that water. You also might be able to stick a wire in there and feel the elbow. Pictures of the valve would help me understand if this is possible.

If you have enough pitch toward the boiler you could possible lower the end of the riser in the basement and see if that gets the lateral running the right way.

If you can find a closet or something on the 1st floor abandoning the pipe and running a new riser is also a possibility.

ethicalpaul

mblucas said:

Ethical: if you click on the link above in hap-hazzard’s post and then scroll down a bit, there’s a pic of the radiator where you can see the valve. What ultimately was the fix for you?

First I tried carefully prying up the radiator. I raised it about 2 inches which stopped the hammer but the lack of heat to the radiator remained along with some gurgling sounds so I knew I still had a pitch problem. I was luckier than you since I could see the pitch problem (which was in my basement where the riser came off the main).

So to really really fix it, I cut out the original riser (it was in an exterior wall and just 1") and am in the process of replacing it with a new riser in my living space, see this thread: https://forum.heatinghelp.com/discussion/177777/autumn-saturday-radiator-repipe

mattmia2

Oh, i see now. I didn't scroll down enough to see the actual convector. It is a convector in a recessed housing, I see how that is hard to work with now. The good news is you could cut an access hole in the floor that would be hidden behind the cover for the convector although it looks like the access is tight enough that to do anything in there you need to remove the element.

mblucas

Short update: radiator now seems to get hot on majority of boiler cycles. Water hammers are still there. Had a senior tech in from new oil company, and he said it could be a wrongly pitched pipe. But he also said it could be rust dams, which I hadn’t heard before as a theory. Mentioned that there’s a chemical additive that breaks them down. Planning to follow up on this.

ethicalpaul

Did he say where these rust dams might be?

mblucas

No--he didn't have much time to look at the system. I'll bring him back at some point to see if they can introduce the chemical additive that he mentioned. It sounds like there isn't much to lose there. Now I've got some gurgling and sporadic heat, which is an improvement.