Steam radiators not heating up

leerla

I've got a problem with 2 radiators in my home. The home is 80 years old, 2 stories, gas fired boiler, with one pipe steam radiators. I bought the house one year ago and my plumber replaced all the radiator steam vents last winter. The house thermostat is in the dining room and unfortunately, that's where one of the radiators that's not heating up well is. The other is in the kitchen. I've replaced the steam vents again with adjustable ones and that hasn't helped. The pipes were not completely insulated, so I've done that but it also hasn't helped. The pipes to these two radiators get hot when the boiler is on, so I know there's heat getting to the general area, but the pipes coming out of the floor aren't very hot, and as I've said, the radiators are too cool. The second floor of the house is uncomfortably warm since the boiler has to work hard to heat the dining room and my gas bills are too high. Does anybody have any suggestions for next steps? Thank you!

Jamie Hall

The most obvious thing...

which I'm sure you have checked, but it's worth asking -- are the valves to these radiators open?  All the way open?  One pipe steam valves have to be either all the way open, or all the way closed.



Do you get any sense of air coming out of the vents on these radiators?



One thing you could try -- but it takes two people -- is to take the vent right off the radiator, and then fire up the boiler.  There should be clear evidence of air coming out (it won't be a great whoosh, but some feel of air anyway).  The reason for two people, is that if this works and steam gets to the radiator, you want to be able to holler downstairs and have that second person turn the boiler off right away!



If air isn't coming out -- and this sounds obvious -- somewhere in the pipes to these radiators there is a blockage.  Could be the valve (see above).  Could also be a hidden valve somewhere else on the line (don't laugh -- I've seen it).  Could be a sag in the pipe.



Tell us more...

Duff

Duff

need more info....are these 2 rad at the end of the steam main(ya have to locate them and the piping in the basement) 

Are there "Quick Vents" at the end of this steam main?) Look  where the pipe drops down at the end of the main. These are also air valves and should be replaced or installed if they aren't even there.

Any banging in the system?

What are the pressuretrol cut in and cut out settings. You might have the cutoff setting to high.

Another biggie is the pitch of the pipe in the basement. And the pitch of those radiators.

could keep going on.....your return piping might be clogged and the water could be stacking up. Have someone who knows steam systems give it a look for you. Or keep typing on the wall and you'll get your answer..Good luck

nicholas bonham-carter

uneven heat

it could also be a lack of main venting, plus over-venting on the radiators on the top floor.--nbc

leerla

Reply to Jamie Hall

Thank you so much for your reply! The valves are all the way open (at least, according to the way the valve says is 'open'). I was originally getting some heat out of them, but now there's not much at all, if any, so it seems like there's no air at all. I just went into the basement and followed the entire length of pipe going to the radiator and most of it is hot, but it gets cold as it gets closer to the radiator, so I'm guessing you're onto something with the blockage idea, at least to the kitchen radiator.

leerla

Reply to Duff

Thank you as well for your reply. I'm not sure how to identify whether they're at the end of the main. I see three steam vents near the boiler, two small ones that look like they were replaced when the boiler was replaced 4 years ago, and one big green one that's about 5 inches tall and looks pretty old. Maybe a good idea to have that replaced.

There is some banging in the system, but nothing horrendous.

I'm not sure where to find the cut off settings, but the cut in is set to 2 and I haven't seen the pressure gauge go above 1psi.

I was hoping this was going to be something simple but I guess it's time to bring in a good steam heat guy. Now, to find one....

leerla

over-venting

Yes, I was wondering if I should change the steam vents on the second floor again to keep it from getting so warm up there.

crash2009

Leerla

What county and state are you in?  Maybe there is someone from around here that is close to you.



Can we see a few pictures of your system.  Could we see a couple shots of the boiler and any odd looking steam contraptions hanging from the ceiling.  I think you said you found the main vents allready (lets see them)

, and especially that radiator valve that says "open" on it.  These pictures can be used to identify what kind of steam system you have, and will help us give you a better idea of what needs to be done.  Also we need a pic of one of the radiators. 



Posting pictures is done by clicking on the File Attachment/Browse button, and go to the place you keep your pictures.  To add more than one, click on the Add Another File button. 

Jamie Hall

It occurs to me to ask

rather late in the day, but... I'm sometimes a little slow.



Do those two radiators ever heat up fully?  Like when it's really cold out, and the boiler runs a long long time? (baking you out of the rest of the house...).  If they do, it is very likely to be a venting issue of some kind, and not a blockage.



Please let us know...

leerla

They're heating up today...

Hi...yes, it's very cold today and the one in the dining room is now heating up all the way whereas earlier it was only heating up partially (I changed the vent again today to a 6...same as the as on the second floor. It was a 4 before). The one in the kitchen is heating up, but not getting very hot. That particular radiator is very small. I put an adjustable vent on it so my question is...should the vent be all the way open or all the way closed? I've read some conflicting information on that from different sites and I'm getting confused as to when they should vent a lot as opposed to very little.

Someone had asked for pics of the boiler and vents and I will try to post some tomorrow.

Thanks again to everyone for all the help!

Duff

duff

Glad your getting some heat now. Balancing a  heating system takes a good under standing of the entire system. Air valves on radiators are suppose to vent that one radiator. Location of the radiator (close or far away from the boiler) as well as the size of the radiator all come into account.But don't give up and remember to always be safe (boiler off) when your making a change on the air valves. Did you ever locate the air valves on the basement ceiling at the end of the steam main?

Duff

duff

Glad your getting some heat now. Balancing a  heating system takes a good under standing of the entire system. Air valves on radiators are suppose to vent that one radiator. Location of the radiator (close or far away from the boiler) as well as the size of the radiator all come into account.But don't give up and remember to always be safe (boiler off) when your making a change on the air valves. Did you ever locate the air valves on the basement ceiling at the end of the steam main?

Hap_Hazzard

The vent can be wherever you want.

Jamie was referring to the valve with the hand-wheel on the end opposite the air vent when he said it has to be fully open or fully closed. Adjustable vents can be set to whatever provides the best result.



The rule of thumb with the fixed vents is to use #4s in the room where the thermostat is located, but that doesn't always work, as you've found. Another rule of thumb is that you need more venting the farther you get from the boiler, but you also need to consider the diameter of the runout. Big pipes hold more air. So if radiators in the room where your thermostat is are at the end of some long, 1 1/2 runouts, they need more than a #4 vent.



The trick is to try to get the steam to enter all your radiators at the same time, not to let some radiators to heat up faster and turn off the thermostat before every room gets heat.

BobC

Venting

The fact the radiators are heating up on a cold day sounds like a mains venting issue. If you trace the piping in the cellar are these slow to heat radiators towards the end of a steam main?



The air vents on the steam main are supposed to vent all the air from the main and leave the radiator air vents to vent an individual radiator and the pipe that feeds it. If a main vent is too small then it won't vent all the air from a main and radiators tward the end get starved for steam, the radiators work on real cold days because the boiler runs longer and the air finally all gets released so the steam can find it's way to the radiators.



There are two basic types of single pipe steam systems. In a parallel flow system the steam main is highest above the boiler and slowly slopes down as it works it's way around the cellar, at the end a pipe comes down and feeds the condensed steam to the bottom of the boiler so that water can be reheated and make more steam. A main vent is usually located around the point that pipe turns down. 



A counterflow system has the main above the boiler start lower and slowly rise till it gets to the last radiator run out, there is usually a main vent in this area.



It's important on both systems that the piping slope is reasonably constant along the pipe run, your eyes can deceive you so use a level to make sure there are no dips in the piping.



You said you have three main steam vents, see how long it takes each of those to get hot from the time the boiler starts up, they should all get hot around the same time. You may have a problem on a main that takes much longer to get it's main vent hot. A simple sketch showing each main and the radiators coming off them might help us see what you are dealing with.



Bob

Mikep

Radiator not working

The radiator works when I take out the air vent . All the other work just fine.

morris31607

Having similar issue, boiler wasn't used for a few years and now seems to not be pushing stream threw the system. Worked well when stopped using it 4 years ago. Replaced all vents and still seems to not be circulating steam. Any suggestions would be helpful.

nicholas bonham-carter

Start a new thread, so you don't get lost here.
Did you replace the main vents as well?--NBC

AnnieMcK

Hi there, Was just reading through this thread and wanted to share this with you - I had a lot of trouble with my boiler/ upstairs radiators when I first moved into my new house. As I was tight for money because of the move I decided to do some googling before calling out an engineer. Luckily I struck gold as I came across a series of videos on YouTube by a company called corgi homeplan, they are incredibly easy to follow and helped me a fix a problem that I may have had to pay £100 or so to have an engineer come out and fix. This is the video that I used https://www.youtube.com/watch?v=VK2Y_uFn56g but there are lots of others on there that might help you!

Fred

Make sure those radiators have a slight pitch back towards the steam inlet pipe. Condensate has to be able to run back down that pipe and return to the boiler. If they are level or tilted the wrong way, water will prevent the steam from getting into the radiator.