Hi we have gas central heating.The boiler is situated with our gas fire in our living room.We very seldom use the central heating.The last time was about 10 months ago.We heat our water by using our immersion heater which is on timer.We decided to put the central heating on yesterday and soon noticed that only the upstairs rads heated up.After googling I turned the rads off and then one bye one turned the downstairs ones on.They all heated up and all the upstairs ones to when I turned them on.All was working fine for a few hours then the heating stopped heating.I checked the pilot light which was alight.Again I turned all the rads off and turned on one upstairs and one downstairs both heated up ok.I only left the two rads on and about an hour later my wife noticed water dripping from the ceiling underneath where the tanks are situated in the loft. I turned the mains water off and turned all the tapps on. I then went up into the loft where I found the water in the small tank red hot.I assumed it was this that was causing the problem. I went and checked the thermostat on the boiler and noticed that I had accidently turned the temperature dial to hot/full on so I adjusted to number 3 which it was set to previously. I am guessing this is why the water got so hot. Anyway after leaving it all for about an hour I turned the mains back on to fill the tanks again.All went fine and no dripping water from ceiling.It was then when I turned on the kitchen hot tap that nothing came through.I assumed it was an air lock and did the washing machine pipe procedure.and turned the cold water on to force the air out.I did this 3 times for about a minute at a time and after a few splutters water came through but only a trickle. I tried another 3 times to get the air out and am now at the situation where I have the flow of hot water at a fast trickle.Every now and againnI get a splutter when I first turn the tap on but the flow stays the same.I would be grateful for any help on this problem also as to why when we first turned the cental heating on on the upstairs rads heated up. Many Thanks.