About a month ago our heating started playing up - randomly not coming on when it should (lights on timer lit up but no action from the boiler) then the next cycle working OK. I've had 2 plumbers in who could find no fault. The last one replaced the timer unit and now the heating is coming on when it should BUT it is taking forever for the radiators to heat up and some are way hotter than others. Timer on at 6.00am. Radiator in my bedroom is stone cold at 6.30am, starts to heat up around 7.00am. Have moved the start time earlier - 5.30am - but absolutely no difference, radiator in my bedroom only starts getting warm around 7.00am. By 7.30am all radiators are warm but some warmer than others and a couple barely warm at all. Plumber has suggested flushing out the system at a cost of approx £600 but can't guarantee this will work. For some reason, the afternoon/evening cycle is better with radiators heating up a bit quicker.
Any advice or suggestions? So fed up with getting up in a freezing bedroom every morning. It's not a combi boiler btw - big tank up in the loft with timer and boiler downstairs in utility room.