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anne marie
Steam radiator only heats w/o vent

My house is pre-1900 and large. I have a steam gas boiler. I have a problem with a two radiators that don't heat when any vent is attached. I have changed vents, checked pitch, etc. Quite by accident I discovered that if I remove the vent the radiator works beautifully. However, as soon as I attach a vent, any vent, the radiator does not heat.
I have changed vents, vent sizes, vent types, etc.

Re: Steam radiator only heats w/o vent

Anne Marie:

This sounds like a one-pipe steam heating system.

It sounds like something is preventing a proper buildup of steam pressure in the particular branch that serves the problem radiator(s)----try checking the MAIN STEAM VENT on the branch piping that serves the 2 inoperative radiators---if the main vent is shot & letting too much steam out, it may be the problem.

Is the water level in the sight glass at the front of the boiler at least half way up the sight glass level???---if not, add some water to the boiler.

Also check the Heating Help site below---they concentrate on steam heat problems---when you get to the site, click at the top of the page onto "Systems", then onto "Steam", then onto "Problems that Plague one-pipe steam systems", or "Two-pipe steam systems" and also, "Problems that plague all steam systems".

Go down the list of possibilities and check the items with your system til you find the problem.

Also check out the Illustrated Home site to see a diagram of the parts of a steam heat system & how they work--click onto the + icon for a larger diagram---do not click onto "Add to cart", as you do not want to buy the images.


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