Maintain your hot water or steam radiators by adjusting the slope of the inlet pipe, checking the valves and vents for blockages and leaks, and releasing air from the system at the beginning of the heating season. Radiators that make loud clanking noises or drip water require maintenance.
Make sure the inlet pipe coming up from the floor is at a shallow slope angling upwards to the radiator. If there is no slope, slide a thin piece of wood under the radiator's legs to lift it up from the floor and create a gentle grade. Ensure the inlet valve is completely open by turning it all the way in either direction, leaving it completely open when the heat is on. Check for leaks or moisture around the valve, and tighten the nuts with an adjustable wrench. If the valve continues to leak, install new packing around the nuts' threads.
To bleed air from the heating system, turn on the heat. Then use a screwdriver or socket key to open the small vent on the radiator's end, and release the air. Put a cup under the vent, and wait until water starts to drip, before tightly closing it. Finally, check the vent for any blockage, and replace rusted or corroded vents.