Steam close to radiator, but leaves me cold

WesternSteam

I have just moved in to an old apartment building, and my apartment is heated (or not) by 3 one-pipe steam radiators.



When I first moved in (in the fall), the front room radiator was putting

out a terrific heat, and the room was a veritable sauna.  Not needing

that much heat at the time, I closed the valve on the right hand side of

the radiator.  This resulted in a fearsome banging and clanging sound

which subsided after a few minutes.  Slowly but surely the radiator

cooled and became cold.



With the arrival of -25 C temperatures here in Calgary, I decided to

reopen the valve and welcome back that much needed heat.  Apparently

this vintage radiator once scorned is a fickle beast.  Although the

valve is fully open, the radiator is not heating.



By feeling around with my hand by the valve, I discovered that the pipe

that leads into the valve (A) is piping hot, while the body of the valve

(B) is very hot, and the inlet to the radiator (C) is cold, which

suggests to me that there is a blockage on the radiator side of the

valve. (Please see attached image)



Since the far side of the radiator was quite cold, I carefully unscrewed

the air release valve as an experiment, and there was no release of

water, or steam.



Can anyone shed any light on what might be restricting the flow of steam

into the radiator?  Condensation? Scale? Spite? I have been in touch

with the building super about it, but he tends to be evasive, and I'm

not sure when he'll ever get a plumber in.  I also wonder  whether the

plumber he gets will really understand an old steam system.  Could I

remove the blockage by closing the steam valve, disconnecting the

radiator, and clearing the inlet (I hesitate to try this with the steam

on, even if the valve is closed), or is this definitely going to require

a visit from a plumber?



Thanks for your advice!

Carl1979

I think the problem is in the Valve [ B ]

The red handle attached to valve [ B ] is my guess for the problem. that handle pulls up a plug inside the valve . and if its broke the plug is just going to sit in the bottom of the valve and not let steam get threw. I don't know if it can be fixed or has to be replaced . hopefully someone else will answer that. or if they think its something else.

For Future reference the safe way to cut the heat off is to turn the air vent upside down that stops the air from getting out so the steam can"t get in.

jpf321

what carl said...but...

you could try lifting the air vent end a but and try to empty any water that may be taped in there..it's an easy attempt at a fix that requires no wrenches but a little muscle...if that helps you may want to lift that end a little bit permanently using something under the feet on that end.

WesternSteam

Thanks for considering the problem, Carl1979

Thank you very much for taking the time to consider my radiator problem, Carl1979.



I can see what you mean, in that if plug has broken off, loosening the valve will still not actually admit any steam to the radiator.



Since this problem has come up, I have been doing a lot of reading about steam systems.  One of the misconceptions I had was that the system was at high pressure.  However, if I understand correctly, the system should be running at low pressure (around 0.5-1.5 psi), just enough to ensure that the steam circulates throughout the system before giving up its heat. 



I suppose this means that a fairly weak blockage (e.g. a detached valve plug) could be enough to prevent the steam from passing through the valve into the radiator?



If the valve were intact, if there was excessive condensation inside the body of the radiator, could that water (or sludge) be enough to stop the steam from entering, or is this unlikely?



If the valve is indeed at fault, I may be SOL, as to repair this would require shutting down the boiler, which I think my super will be reluctant to do, at least until it warms up.



I guess it would be a bad idea to close the valve and disconnect the radiator to inspect the inflow (or drain any liquid) while the boiler was running?  I suppose I would be taking the chance that the valve would hold back the steam effectively.



Thank you for the tip on cutting the heat safely.  Now that I understand the function of the air vent, that makes a lot of sense.  Is it possible to retrofit a variable air vent that is not just on / off, but acts like a thermostat?



Thanks again!

WesternSteam

Lifting end

Thanks for your time and thought, jpf321.



One of the first things I tried after I started reading about steam systems was shimming the air vent end.  I noticed the radiator has sunk slightly into the floor, and I was wondering whether this was preventing condensation from running out correctly.  I was only able to raise it about 1/2" at most.  I left it overnight like that, hoping that I would feel a change in the morning, but as far as I could tell, nada.



I'm trying to picture what could be going on inside this thing.  Are we potentially talking like an inch of water, pooled at the bottom and resisting the flow of steam through the inlet port, or am I misinterpreting the physics of what happens with a blockage?  I've been having a hard time picturing how water could block the steam.



Thanks again.

jpf321

it was a long shot...

more likely a broken valve...chances are there isn't enough water to completely block steam flow..steam will never go where water or air are..they always block steam flow if they exist in its path.

Jamie Hall

Not really a good idea...

to disconnect a radiator -- for any reason -- when you don't have full control over the boiler.  Steam burns very badly if it gets on you, and even if it doesn't live steam in a room is not something you want.  So that's out.



I am really concerned about that valve, though.  I suspect that it may have been damaged when it got turned off (don't feel bad -- how were you to know?); the banging and clanging was water and steam fighting to get past the closing and almost closed valve, and could very easily have damaged it enough so that it won't open again.  That's a job for a plumber, unless you are really handy with plumbing tools yourself -- and can be sure that the boiler is off and stays off while you work.



I doubt that enough water could be trapped in the radiator to block the steam completely.  More likely, you would hear a cheerful gurgle when the boiler came on.

Rod

Probably Need a New Valve

Hi- As others have said, you don't work on the piping system if it's hot and you don't control the boiler. I've attached a diagram on a 1 pipe steam radiator which might be of interest to you. There is also a device called a TRV (Thermostatic Radiator Valve) which allows you to control the amount of heat the radiator puts out. It doesn't increase the heat, it just keeps the room from getting overheated. The model for a 1 pipe steam systems goes between the radiator and the radiator vent.

- Rod

crash2009

Have you tried to force the steam to go in there?

  Remove the air vent and vacuum the air vent hole.  You likely need to vacuum for about 15 minutes.  If the vacuum can pull the steam through, the valve is still open.  Once you get some heat in there you may get lucky and the radiator will continue to heat by itself.

nicholas bonham-carter

bonnet removal

that valve can be inspected for a dropped disk by removing the bonnet, just under the handle, and packing nut. unfortunately, the boiler would have to be turned off completely, while doing this. the advantage is that this does not break the seal of the union of spud to valve.

perhaps you can get your landlord to take more interest in this, if he thought his pipes might freeze. ask him if his insurance is up to date on water damage.--nbc

WesternSteam

Thanks

Thanks for your advice, Jamie. 



I will stay away from disconnecting the radiator, then.  The only noise I've heard the radiator make, apart from the banging I referred to when I closed the valve is a hissing sound from the air valve, again, once I had closed the steam valve.  I would guess that was the sound of air being pulled into the radiator as steam that was trapped in the radiator condensed and cause a partial vacuum?  I never heard a hissing while the radiator was in operation, which surprises me, since from what I've read, an occasional hiss seems to be par for the course from a steam radiator Of course, that radiator, even when it was heating, never actually heated up that much on the air valve side. 

WesternSteam

Thanks

Thanks for the advice on the TRV, Rod.  That sounds like just what I need, once the radiator actually starts heating up.  Once it's going it gets incredibly hot, probably too hot unless we're at -25.



Also, thanks for the diagram.  It's exactly what I needed to visualize what goes on with the flow of steam and water in a one-pipe, and the problems that arise during shutoff.  This radiator has now become a curiosity for me as well as a practical problem, so it's satisfying to know how it should work, even if it isn't at the moment.  Much appreciated.

WesternSteam

I might well try this

Thanks for the suggestion, crash2009.  The thought had crossed my mind that reducing the pressure inside the radiator might encourage steam to enter, either by pulling up the broken off rubber valve tip, or getting the steam past an obstruction.  I might give this a try if the super keeps stalling on the plumber.  Have you had success yourself with this approach?

WesternSteam

Thanks

Thanks, nicholas.  Sounds like I have to convince my super to shut down that boiler for the repair.  Luckily we're in the midst of a Chinook here, so the temperature has gone up almost 30 C over the last week.  This coming week would be a good time to do it.  I might try the water damage line of reasoning, although he's known about my leaky toilet for 3 weeks now, and doesn't seem too perturbed

crash2009

Yes

 On two occasions now I have had radiators just go stone cold and refuse to come back on after the valve is opened again.  This usually coincides with the tenant shutting of the valve for a long time.  I am sure someone here could give us a scientific explanation of why it works in some cases.  I usually test the radiator first by taking the vent off and putting a lit match up to the vent hole.  If the valve is closed the match just burns normally in to the room.  If the valve is open the flame of the match will do one of two things.  Either it will get sucked in or blown out.  There was one time that the flame was kinda doing the tango in-in-out-out-in.  Put the vacuum on the vent hole for 15 minutes, and feel the radiator, if the valve is open steam will come in, and once the radiator is warmed up (at least in my case) it will continue to stay warm all winter.  If you have success with this, and you find the radiator is too hot for your room, buy yourself a TRV and 2 street elbows.  Put it all back together and use the same vent. 

WesternSteam

APPEARS TO BE SOLVED! Thank you!!

This afternoon I went to the hardware store and did a bit of improvising to cobble together the device shown in the attached image.  It allows me to couple the hose of my wet/dry vac with the 1/8" F.I.P. hole where the air vent attaches to the radiator.  I included the ball valve  because I wasn't sure what would happen when I engaged the suction, and wanted to be able to shut off the line in case the steam was coming out forcefully, and I couldn't decouple from the radiator.



Well, I hooked it up and hit the on button of the vac for just a few seconds to see what would happen.  Instantly the clear plastic line filled with condensation.  I couldn't see any evidence of steam, so I hit the on for a few more seconds.  Then I reached down by the steam valve to feel area C in my original image.  What do you know? The heat had migrated past the valve.  I quickly decoupled the tube from the air vent hole and replaced the air vent.  Within 2 minutes the first two radiator elements were scorching hot. 



The radiator seemed to be progressively heating up, but after waiting for another 10 minutes, for the heat to migrate further, I got bold and decided to engage the suction again.  This time I kept feeling the radiator elements to determine how far the steam had been pulled.  When it seemed like the steam had reached the second last element, I decoupled again (this time the fitting and hose were quite hot!) and replaced the air vent.  Currently the whole radiator is hot!



I'll report again if it quits on me, but it looks like the suction did the trick.



Thank you so much for taking the time to help.  This has resolved an issue that has been troubling me for over a month now, so it's a major weight off my mind.  This is truly an excellent forum!

crash2009

Glad it worked for you

  Wish I could remember who told me about that one, and give them the credit.  Somebody suggested that to me last winter. They also told me about the flame test.  It might have been JSTAR.  I seem to remember he and others helping me with a cold rad last winter.  Our place was in real bad shape, and I got a lot of help here from so many.  Its hard to remember who suggested what, when you are in a desperate situation, and trying so many different things. 

That rig you built, looks like it would work a lot faster than just holding the shop vac hose up to the hole.   

There probably is something wrong with our valves, yea mine too, otherwise they would just work, and not need to be vacuumed.   Your landlords whole steam system probably needs a tune up.  Its so hard to get things done in a rental property.  The real problem is likely in the apartment with no apparent problem.  Try explaining that to the apartment with perfect heat. 

Chinook..... Its been awhile since I kept my eye on the Idaho high! http://en.wikipedia.org/wiki/Chinook_wind

How are the Flames doing this year?  Oilers?