Baxi Maxflow Combi Fs?

The heating system works only if there is a call placed on the water ie actually running the water. Once this is satisfied and the boiler fires up even if there is no demand for Central Heating the Heating kicks in and doesn't go off unless you turn the water control down on the front panel.??

Now if i Leave the Heating on timed the boiler still kicks in and the orange gas light kicks in as it should and the light for the radiators lights up on the boiler but doesn't warm the radiators up?

Have changed the Diverter Valve but still the problem persists?

Some have suggested Water Pump, powerflush, and possibly main pcb but i dont know which one to do next. Don't know if it could still be the diverter valve even though its new??Twice stung etc?Help required pls!!