I have a Worcester Bosch greenstar 25Si which is approx 6 years old I want the boiler to run in pre heat mode but although I turn the eco button off ( no light on so manual stated that this is pre heat mode), the boiler keeps turning the eco button on (light on) so no pre heat I’m fed up with keep turning it off as the boiler is up in the loft It is controlled via a Worcester digistat in the hallway Any ideas on how to keep the boiler in pre heat mode Many thanks fir any advice offered