How does a bleeder valve work?

Radiator bleeder valves have many names, adding bleeder valve, release valve, and bleed nipple.Image result for hydraulic bleeder

The objective of the KP-LOK bleed valve is to release air that sometimes get trapped within the radiators making them less efficient.

The valves contains a plug that screws into a radiator tapping at the top of the radiators, and an adjustable bleed screw, with a 5mm square head, in its hub.

The plug, which generally has a half-inch British standard Pipe thread, is screwed into one of the 2 top tappings – internally threaded holes at each side of the radiator.

Bleed screws on most new radiators also have a slot in the head so they can be tightened and loosened with a screwdriver.

Some plugs have external hexagonal heads that can be changed with an ordinary spanner of the best size, or an adjustable spanner.

Other have a square recess, also called as a square section, which is removed or fitted with the square end of some multi-objective radiator keys.

Turning the bleed screw anti-clockwise with a bleed radiator key releases any air. Turning it clockwise tightens it up again.

How to bleed a radiator

If a radiator is chill at the top but warm at the bottom when the system has been on for a while, it likely means there is air trapped in it.

Bleeding the radiator will remove the air and restore the radiator to right working order.

Turn TRV to high…

First, ensure that the thermostatic or manual radiator valve, at one of the base corners of the radiator, is turned as top as it will go.

Open manual valve

If there is no TRV, you must have a manual valve.

To completely open it, a manual valve is just turned anti-clockwise by hand until it prevents.

Run system

Run your central heating system for 10 minutes, then turn it off.

Locate air release vent

You will find the air release vent at 1 of the 2 top sides of the radiators. It is recongisable from the square-headed vent screw in the middle of the vent plug. In some cases, the vent screw is set in which looks like a plastic insert in the air vent plug.

There may be a slot for a screwdriver in the finish of the bleed screw but it is generally simpler to use a key, which would not slip so simply.

Find an old cloth

Ensure you have an old rag or cloth to catch the fine spray of water you will get at the critical level of the operation.

Fit and turn bleed key

Fit and bleed key onto the bleed screw and turn anti-clockwise. If the valve is still or has the  tightened extremely firmly, this may need quite a bit of force.

Re-tighten bleeder valve screw

Fast re-tighten the bleeder valve screw, nipping it up fairly tightly, but not so tight that you destroy the bleeder screw.

Re-adjust TRV

Turn your manual or TRV valve back to the wanted setting.