Radiator Bleed Key – Standard Brass

The Radiator Bleed Key – Standard Brass is the simple key that fits the square spindle on a radiator bleed valve. Turn it, let the trapped air out, and the radiator heats from top to bottom again.

When to use a standard brass bleed key

If the top of a radiator stays cold while the bottom heats up, trapped air is the usual cause. That is normal after a system has been drained, and it builds up slowly over time too. Bleeding takes a minute per radiator with the right key. Brass keys are stronger than the thin pressed ones that come free with radiators, so they are less likely to round off a stiff valve.

Specification

• Material: Brass
• Suitable for: Standard square radiator bleed valves

Common Questions

Why will my bleed key not fit the radiator?

Some rads use a hex socket or a slotted screw instead of a square. Check the vent and use the key that matches.

Which way do I turn a bleed key?

Anticlockwise to open, a quarter turn is usually enough. Turn it clockwise to close once water appears.

Is a brass bleed key better than a pressed steel one?

Brass is thicker and stronger, so it is less likely to bend or round off a stiff valve. It also lasts longer in a tool bag.

Bleeding tips for Glasgow homes

Switch the heating off and let the radiators cool, so you do not get a jet of hot water. Hold a cloth under the valve, turn the key anticlockwise a quarter turn and wait for the hiss to stop. Close it as soon as water appears. Start downstairs and work up. On a sealed system, check the pressure gauge on the boiler afterwards and top it up if it has dropped.

The Radiator Bleed Key – Standard Brass is in our brass fittings section, along with the clockwise pattern version.

Grab one at the Plumb Parts counter, 555 South Street, Glasgow G14 0QX, Mon-Fri 8am-5pm or Sat-Sun 8am-1pm, or order online with other parts.