On which parts of the radiator can radiator wrenches be used?

	Before looking at the different types of radiator wrenches and how they are used, it is helpful to know the different radiator fittings they can work with. There are various wrenches and wrenches for installing, removing or adjusting all the radiator parts described here.
Taps
	The rectangular central heating radiator has four outlets, one at each corner. Taps are holes with an internal (female) thread. They may look like short pipes with an open end before the fittings are screwed into them. Fittings with an external thread (male thread) are screwed into the outlets, which allow you to make various adjustments to the radiator.
Valves and valve stems
	The two fittings that go into the taps are valves that control the flow of hot water to and from the radiator.
	Thermostatic radiator valves (TRVs), manual valves and shut-off valves are connected to the radiator outlets by a valve stem. The tail of the valve is screwed into the thread, then the valve is connected to the shank by the so-called nipple connection. This is a nut with an olive - a brass ring, which, when the nut is tightened, is compressed, forming a seal. Double-sided wrenches, socket or hex wrenches, radiator wrenches, allen wrenches, ratchet wrenches, combination wrenches, and sockets are used to remove and install valve stems.
	The valve stems on most modern radiators have a fixed external hex (hex) or square (four) nut built into them. They can be equipped with an open end wrench or adjustable wrench, as well as a socket head shank attached to an electric drill.
	However, instead of external nuts, some valve stems have an internal hex shape. They are fixed or removed using hex-shaped radiator wrenches.
	Some other valve stems have bayonet fittings or female lug fittings. The ears are small metal spikes. The grooves in some radiator keys slide over the lugs and the key turns to install or remove the valve.
	Usually either a manual valve...
	...or TRV mounted on one of the two lower radiator hoses.
	Sometimes a manual valve or TRV is installed in one of the overhead outlets due to the special design of the radiator.
	The check valve, so named because it is covered with a plastic cap to prevent adjustment when not in use, is attached to the other bottom outlet. Whether a particular valve is installed on the left or right depends on the direction in which the water must flow through the radiator. A manual or thermostatic valve is usually an inlet or flow valve, and a check valve is usually an outlet or check valve.
	The shut-off valve can be adjusted to increase or decrease the flow of hot water through the radiator. Removing the cover reveals the top of the spindle which can be turned with an adjustable wrench to adjust the flow. This is called balancing the radiator. Some stop valve caps must be unscrewed before they can be removed. Others just push on.
Vent plugs
	One of the top two outlets is fitted with an air bleed plug which has a bleed valve, sometimes called a bleed valve, to bleed any unwanted air or "bleed" the radiator. They vary in appearance, but most have the same square-head bleeder screw in the center, sometimes called a bleeder pin. The bleeder screw head is usually 5mm square. When the screw is sufficiently loosened, air is expelled through the nozzle first, and then some water, before it is tightened again.
	If the air vent plug is equipped with an external (external) hex nut, it can be installed or removed using an open end wrench or adjustable wrench.
	Some radiators have square internal plugs, known as square sections, that can be installed or removed using the square end of a double ended hex wrench or Allen wrench.
Stubs
	The other top outlet is provided with a plug which simply closes the opening through which water might otherwise flow. They can have hexagonal heads, like this one, square heads, or square-section recesses.