@Blooflame - Yes I will do that, but do I return it to vaillant?
@The831Bunny - No, the water is green as I've added anti-freeze and yes my magnaclean filter is on the return pipe to the boiler, its connected just under the boil. But I only soldered the pipe which comes out of the magnaclean filter, the pipe which enters water into the filter is joined using compression, does this affect the performance? There is sludge in the filter, but not much.
WTF....Antifreeze?? Is this a windup mate. If u have indeed put antifreeze in the system.. I'm out of here b4 I make an extremely rude comment. That will almost certainly void your warranty.