Hi I have an icos 24he central heatin boiler which on the surface looks to be working ok with no error codes. The propblem is I can't get get hot water and heating at the same time. If I turn the heating off and leave the water on constant as recommended the tank temp runs at the system norm of 80 when I turn the heating on the boiler fires up as normal but the tank temp drops to just over 40!! resulting in poor heating and cool water even tho' the boiler is still fired up it never gets above 45. The system is runnining 13 radiators and the boiler is seviced yearly. Be grateful for any advice on what posssible problem is and I can do.
Jack
Jack