In this video, This Old House plumbing and heating contractor Richard Trethewey explains how to maintain a steam radiator.
1. Close the valve at base of radiator.
2. Turn off the room's thermostat.
3. Carefully unscrew the old air vent from side of radiator; if valve is hot, use thick cloth to protect your hand.
4. Wrap Teflon tape around the threads of the new steam valve.
5. Thread new steam valve into side of radiator; be sure valve points straight up.
6. Remove handle from valve at base of radiator.
7. Use adjustable wrench to unscrew packing nut from valve stem.
8. Wrap graphite packing gasket around threaded valve stem.
9. Replace nut and tighten with adjustable wrench.
10. Open valve at base of radiator.
11. Turn on the room's thermostat.