Bleeding Central heating All aspects of plumbing questions and answers, help, tips and information

[daniel foss]

I have just fitted some new radiators which required draining the system down as some pipe lengths needed to be altered.

I need to find the correct method of bleeding the system, usually I bleed the radiators, pump and 2 high level bleeders (1 above the pump and 1 at the top of cylinder coil) with the system turned off however there is still air in the system as it gurgles and bangs away when first starting up.

Also 1 of the rads, furthest from the pump won't heat up so guess an airlock is to blame.

System is indirect vented.

Thanks, Daniel

[htg engineer]

Fill from the bottom up - all downstairs rads, upstairs rads, then the two manual airvents, and also the pump.

There's nearly always some air left - it wont harm anything. To solve the problem with one rad not heating, turn off all other radiators and see if it comes through.

htg