1/2 of Radiator is Hot

Concerned Apartment Owner

I live in s high rise in NYC and have a through wall A/C unit. In the winter time the fan unit blows air across the heating coil. The building has a low pressure steam system. At times when the fan is on only 1/2 of the radiator is hot. The side closest to the steam supply of the unit. I curious to know what is in the cold side of the radiator. Is it steam that has condensed or air? Is this caused by the steam pressure being too low? Is there a minimum pressure differential between the supply side and steam trap side of a radiator to insure sufficient flow? Should I have a steam pressure gauge and a vacuum pressure gauge installed LOL

Vermonter

What's in your radiator...

There's air in the cold side... and steam in the hot side. When the steam condenses it turns into water and flows back down through the supply valve and eventually to the boiler.

If it's only 1/2 hot that means that it hasn't fully filled with steam. This isn't a problem unless you're cold. If you are, then the solution depends if you are allowed to change the radiator or if the building super needs to do it. If not don't worry about gauges etc, just adjust the air vent on the "cold" side of the radiator to let the air out faster when the steam's trying to get in. If you don't have an adjustable vent then maybe it's time to replace it. Be sure to check that it's free of paint that may block the hole a little.