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Clogged steam radiator?

Is it possible for a steam radiator to become clogged internally?

Here's my scenario:
I know there is steam coming into the radiator from the main valve. The valve is fully opened. The steam comes into the radiator, but only warms the first 2-3 sections of the radiator that is about 8 sections wide. I removed the air valve, and no steam comes out, even when the system is running.

Is it possible that there is some sort of clog inside the radiator that is preventing the steam from fully passing through all of the sections?

Re: Clogged steam radiator?


Check the BALANCE of the system first.

Remove the air valve from the offending rad & use a bike pump to pump bursts of air into the rad & supply pipe---station someone downstairs---the air should be heard exiting the main branch vent for that pipe.

Check the air vent on the main branch in the cellar to make sure it's open when cold & closes when steam arrives---you might not be getting enough steam in that branch of the piping---it may all be going to other piping branches.

The main vent has to close after air is expelled & it heats up to deliver the steam to the rad where you're having trouble.

Cold, you should be able to blow thru it when you remove it---place it in a pot of boiling water on stove-- should close when hot---if it's not functioning, steam will escape into the cellar & very little will get upstairs.

Sometimes rads don't heat all the way across because room temp is satisfied in mild weather---they put out more heat in cold weather cause they're constantly running.

Check the PITCH of the piping to the offending rad with a torpedo level---the piping should tilt BACK TOWARD the boiler so condensate (cooled steam) can make its way back to the boiler.

If it's not tilted right, water will collect in the piping near the rad & prevent adequate steam from entering the rad.

If all these test fail, disconnect the rad & see if there is any sludge in the hoizontal section of the riser pipe & clean it out with a long screwdriver or long stick---use a garden hose to clear stubborn pipe clogs, most systems provide a flush valve in the cellar main for this purpose.


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