i have a 15 yr old Potterton Suprima that has worked well over the years without any probs. This morning I heard the boiler making some noises and the rads not warming up, which I have never experienced before. When I checked the system I noticed the fuse to the power supply to programmer had blown and continued to blow after new fuses were put in. I put in a higher 5A fuse, the boiler fired up, made noises and went into reset mode, blinking green light. Can anyone help, is it a simple problem or time to replace?