I have a Heatline Central Heating System that has just started heating the upstairs radiators only. Unfortunately it is 3 weeks out of warranty. I was suspecting a block in the system so I turned off the upstairs radiators to try and force the water to flow into the downstairs radiators. The downstairs started heating up but when I turned on the upstairs radiators the downstairs became cold again. Strangely the hot water is now warm next to cold. When I restart the boiler I can hear the pump kicking in which I assumed that it is worked (not sure if I'm correct). I called a plumber who came to assess the boiler but he wasn't sure what was wrong with it. Please help me my family is freezing. Thanks