Boiler is On, though digistat is not calling for heat?

Hi

Replaced the batteries 3 days ago, as i had some of the same problems as the others, boiler fired... but then its been going since... Digistat is not calling for heat, it is 23C and it is set to call for heat when it is 21C???
Any suggestions? Have tried to turn the boiler of and on... No fix.

Helene