central heating rads on the blink

[stevea4117u]

please help me going mad!
I have a problem with central heating had a lot of crud in pipes that where causing blockages in system. I have taken every rad off and flushed each one and then flushed each pipe out and those that would not clear have been replaced. I have also replaced the air seperator that sits above the boiler (that had some crap in it to and also had a pin hole in it). I also flushed the heater tank inside the boiler and cleaned the thermostat. reset refilled the system and it is again getting hot but after some time it sounds like its blowing bubbles into the header tank in loft and sending boiling hot water to it. i'm running out of ideas could anyone please give me some advice as to what I do next????????

 

[bathjobby]

You say it 'sounds like' its blowing bubles into the header tank. Have you actually checked to see if it is doing that, rather than it pumping over ? If it is doing what it 'sounds like' then I'll leave it to others here to help, but if it is actually over pumping, then you may want to read this old update from me in this item; //www.diynot.com/forums/viewtopic.php?p=260097#260097