: I have a hissing steam radiator that makes such a loud noise that it wakes me up at night. I try shutting the radiator off using the shutoff valve but this doesn't alleviate the problem. Also, there is a lot of water leakage from the air valve. It is a one-pipe system. What can I do to eliminate the loud hissing and the leakage? Should the air valve be screwed all the way in or only halfway? My air valve is of a conical shape. Which direction should the pointy tip face?
The pointed end (with the hole in it) should be facing straight up. The hissing is normal, it is air being released from the radiator but should stop when the rad is hot. The valve that you shut off is a service valve, they rarely hold 100%. The reason water is shooting from the vent is because the steam is still passing by the valve and the condensate cannot drain back properly. Replace the air vent and keep the service valve in the fully opened position.
Good Luck. e-plumber