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ouch202 11-26-2010 08:29 PM

Steam Radiators Problem
Hi everyone, this is my first post.. I'm hoping you all can help me out with an issue I'm having.. I'd appreciate any help or input that anyone could give..

I have a house that runs off steam heat (oil)... I only just started using it about 2 weeks ago. I grew up on electric heat and I don't know much about heating systems but I have been researching this issue all day online... here's the story..

the boiler was just serviced recently and everything is working a-ok as far as that goes. (As far as I know). However, every 4 or 5 days I find myself adding a little bit of water into the boiler as the low water cut off is coming on. (It appears to be about 1/2 inch under the halfway mark.. I fill it back up to the halfway point.. and a few days later it's back underneath there again). There aren't any leaks downstairs so that means the "leak" is coming from somewhere else.

Now, the radiator in the room above the boiler (which I would think is the first one to get steam from the boiler?) one room hisses VERY loudly for 20+ minutes every time the heat is on and the boiler is running. It doesn't shut up until the boiler turns off. If I keep the door to the room shut, Condensation builds up on the walls (similar to how a mirror fogs when taking a hot shower), and it gets super warm in there.. very quickly. It's my master bedroom. I've actually started turning down the heat at night when I sleep to a point where it doesn't come on, because it's so loud it wakes me up.

I think what is happening is that the hissing noise is steam is escaping out of my radiator, which in turn means it is not turning back into water, and that's accounting for the amount of water that is disappearing out of the boiler.

When I researched this, the most common solution appears that it could be the air vent not closing... it could be letting out its necessary air and then proceeding to let out steam afterwards... I talked to someone else and they said it could be a "pressure relief valve" in the radiator as well. I have no clue what that does or where it is located or how to go about replacing it. Does anyone have any thoughts about what can be causing this? Is it a DIY?

fitter1 11-27-2010 06:06 AM

Good info. Yes the rad.vent is stuck open, Some can be cleaned or just replace it. Make sure boiler is off so you don't burn yourself. If you have a water feeder, the inlet screen could be clogged or you could have a manual feeder, [a hand valve]. The pressure relief safety valve is on top of the boiler which is most likely set at 15lbs. Some rad. air vents are adjustable and numbered 1-5 and act like a relief valve in order to balance your steam radiators that will let out the air and close off when steam is present.

ouch202 11-27-2010 08:51 AM

We have a manual water feeder, not an Automatic one. Is it difficult to replace the air vent? I know to let everything cool off and make sure the boiler is off before attempting to remove it.

yuri 11-27-2010 09:26 AM

May look simple but they can get corroded and literally break/snap off inside the fitting in the rad. Threads can get stripped and then you need an experienced Pro plumber or fitter to cut them out/rethread the opening or install a bushing etc. While you wait for the Pro you have no heat or have to shut off the rad valve which itself can leak when you open it later. I did LOTS of work on old steam systems and rads in a hospital and know all about it. I would hire a Pro who has steam boiler knowledge (not all do) as he should have the fittings etc in his truck.

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