Boiler sounds on when not asked for

We've just recently moved house and we have a Ideal Logic+ system boiler. Every now and again the boiler sounds on but we've not asked for it to be in and the indication on the panel indicates the letter C which in the manual say "the boiler has called for central heating/hot water but the appliance has reached the desired temperature set on the boiler" Can someone please tell me in everyday language what that actually means? Thanks