if you cant fill your boiler from the fast fill its more than likely that the valve inlet has got blocked... if theres no inhibitor in the system the valve inlet where the water flows through to the boiler blocks with crud ( calcium carbonates) turns hard and compleatly blocks the hole ( plugs it )
The only way is to drain down the boiler and remove the valve and strip the side where it fills , clean it out with soapy water and poke out the blockage with a pin..This can then be put back together and ptfe tape can be used to seal any threaded joints... I would flush the system out compleatly and then add a good inhibitor (sentinol) by adding it into a radiator and then refill your system.... powerflushing is another option but with combi's is just as easy to add a cleanser to the system, run it round for a while then simply drain and flush the system again, making sure you add a inhibitor before the final fill up.... hope this helps :)
jase, March 2010
