Central Heating banging after bleeding radiators?

Laz123

Seronera wrote: »

Crinklmeister is quite correct of course. I'd just ask additionally if you bled the radiators with the system turned on or off. It should be off when you vent rads. So repressurise to 1 bar when the system is cold, set the system going, then check radiators again. If not hot at the top, turn system off, vent the radiator just until water appears, tighten vent and top up pressure again at boiler.

That should sort it out.

Maybe I'm wrong but I've always bled rads when on and hot and this is when any trapped air has hissed out, starting farthest from pump working to nearest.

richy999

rockin_plumber wrote: »

The fact you mentioned it only started when you bled them may make this theory wrong...
Unless a lot of the radiators you bled weren't working until you did so????

That was my thinking. If the system was in dire need of being bled, it wouldn't be working effectivley and getting up to full temperature.

Now the system is properly bled and all radiators are working, you are getting more of the usual noises. Perhaps a full flush followed by some Fernox Boiler Noise Silencer might help but you will always get some noises as the metal components in the system expand/contract with heat changes... especially if they are tight againts joists/floorboards etc.

geordie_ben

There was a 3 radiators upstairs that weren't hot all the way to the top

I started closest to the boiler, but they were all full 99% anyway

The banging noise seems to be more in the radiator and the pipes, than actually the pipes knocking against joists etc

I've turned the temp of the radiators down on the boiler, but this hasn't help