Steam vents on radiators

Servicewiz_3

I would like to know if anyone has any sources for info. on
steam radiator vent location? I know it must be on the side
because steam is lighter than air. I would just like more sources
for a class I am instructing. Thanks!
JVS

ethicalpaul

I believe The Lost Art book on this site goes into some detail but the short answer is on the side opposite the valve about 1/3 down from the top.

ps: it’s typically called an air vent because it vents air then closes when steam hits it, ceasing to vent at that time

bburd

More like 1/2-2/3 down from the top. There’s a drawing in LAOSH showing that the lower position allows more of the radiator to heat.

ethicalpaul

Thanks. This one is by my front door and has made me forget

Additionally, I was off-base on my statement about what to call the dang things. On Maid O Mist's website they call them "Steam Vents" so I'm 0 for 2 on this one

Supplyhouse calls them Air Valves and that's just crazy