Radiator Bleed Valve
Also known as: bleed nipple, air bleed, bleed screw, air vent
A small valve at the top corner of a radiator used to release trapped air. When air collects inside, the top of the radiator stays cold while the bottom is warm — bleeding fixes this.
Top corner of every radiator, usually opposite the TRV or manual valve.
Small square or slotted brass fitting, 1/8 inch BSP. You need a bleed key (square) or flat-head screwdriver to open it slightly.
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Always turn off the water supply before replacing any part. If in doubt, consult a qualified plumber. Gas components must only be worked on by a Gas Safe registered engineer. Unvented (pressurised) hot water systems must be worked on by a G3-qualified engineer. Prices shown are indicative — check retailers for current pricing.