New member here. I had no hot water but the boiler fired up when a tap was opened. The central heating was working perfectly. The 3amp fuse blew overnight which suggested an electrical fault so I replaced the 3-way motor and the diverter valve. Now I have perfect hot water and the boiler fires up for the central heating according to the temperature control. I have it set low at 61-64 degrees, and the water is gravity feeding one of two radiator upstairs, the other is cold. The feed to the downstairs radiators is cold below the T-junction to upstairs. The pump sounds like it running OK so I am at a loss as to what it is. Thought about shorting 1/2 on J10 as per manual to see if it is the 230v control board? Anybody find this story familiar please?