If the valve in your radiator heater becomes defective, you may notice a lack of heat in your home. Radiator heaters use water to heat a boiler and circulate the hot water through tubes connected to the radiators throughout your home. Radiator valves contain extremely hot water. Replacing a radiator valve does not require extensive skill and can be accomplished by do-it-yourselfers. Once the radiator valve is replaced, you should notice heat radiating through the heating elements in your home.
Tighten the bonnet (nut) on the stem of the radiator's valve with adjustable pliers. If this does not stop the leak, continue to the next step.
Shut off your radiator heating system and allow it to cool by turning the inlet valve knob to the "Off" position. Loosen the stem vent located at the top or on the side of the radiator with a screwdriver. This allows any trapped steam to escape from the radiator before you repair it, preventing possible injury.
Open the radiator's main drain until all the water in the radiator drains past the valve. Place towels on the floor under the main drain to soak up the water as it will drain onto the floor.
Remove the valve of the radiator. Position two adjustable wrenches at each joint of the valve and twist until the valve loosens and can be removed from the radiator.
Coat the threads on the new valve with radiator joint compound and install according to the manufacturer's directions. Typically, position the new valve in the designated area and tighten onto the radiator with two adjustable pliers.
Tighten the bonnet on the new valve with the adjustable wrench.
Turn on the radiator at the inlet control knob by turning it to the "On" position. Verify steam releases from the steam vent and close the vent by turning it with the screwdriver.
Inspect the new radiator valve for any leaks.