Steam radiator question

If you take a radiator vent off entirely and don't replace, what should happen?


Off the side of the radiator?

The vent is designed to let air out of the system to allow steam to rise up and fill the system, which heats the pipes and radiators and makes your tootsies warm on chilly November nights. The valve is designed to close when the steam reaches it, so steam stays in the system.

The boiler keeps firing until the thermostat reads the temperature you set.

If you leave the valve off, steam will fill that boiler and start escaping. It will keep escaping until the boiler stops firing. So at the least you'll be losing steam from your system. If the valve is way at the end of the system it may not amount to much, but if it's close to the boiler you could lose a lot of steam while the rest of the system is heating up.

You'll end up having to add water to your boiler much more frequently.

There are probably other ramifications because a steam radiator system has to be kept in balance to function properly, and an open hole in part of the system is going to throw that off. 


The steam that would be released will also damage your wall and any human or animal that gets too close will be scalded.  It is quite dangerous.

Thanks.  That's what I thought.  I did it as a test--a radiator that doesn't seem to get fully hot.

So what did happen:  nothing.  Then it was a while (day + night) before I found a spare vent to test, though I was pretty sure that wasn't it.   By the second day, it did get warmer, and I heard the light whistling sound you might hear from a vent.

But never any steam release.

So, bad radiator?  Something clogging in there?

I did check to make sure it's fully on--and when I closed that, the whistling stopped, came back when I re-opened, so that seems ok.


There are different sizes of air vents that let out more or less air, so you need to find the appropriate size.  Roughly, the larger the radiator and the further away from the boiler, the faster the air needs to be released (i.e. the larger the air vent size) so that all of the radiators get hot at the same time.  I balanced the radiators in our house shortly after we bought it.  Every time the heat kicked on, I would run around the house feeling the radiators.  My goals was that they were all halfway hot at the same time.  It took awhile, and a lot of different air vents, but it was worth the effort.


Is the floor value working? -Can you tell if it is fully open?


steel said:

Is the floor value working? -Can you tell if it is fully open?

 A broken floor valve will often rattle or cause banging.  Does it make noise?

Another thought -- is it by any chance the last unit on the line?  Often there is a vent on the line itself at the end, and if that vent is shot, it can slow or stop steam getting to the last radiator.


max_weisenfeld said:

 A broken floor valve will often rattle or cause banging.  Does it make noise?

Another thought -- is it by any chance the last unit on the line?  Often there is a vent on the line itself at the end, and if that vent is shot, it can slow or stop steam getting to the last radiator.

 If it's far down the line from the boiler, a few things could be happening.

One thought: The radiator in the room with the thermostat is heating up too fast and he thermostats is shutting off the boiler before the entire system heats up. The vent on that radiator might be oversized for what should be in the room with the thermostat. 

The room with the thermostat should have a #4 vent in it.


No banging noise.  Floor valve seems to work--definitely all the way open.

It's the only radiator on its branch off the main loop, but not the farthest.

thermostat room has a #4 and is working fine.

It's a new boiler and new main vents.  Have been doing the running around checking radiators thing and it's working well, though still some balance issues (mostly upstairs too cold).




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