worcester 25cdi boiler flashing up code ea IN SUMMER?

we had a very wet day here a few weeks back, the kind that lifts drains etc. we returned home to find an awful lot of water on our work surfaces and floor near where boiler is and boiler flashing ea. we have had a plumber look at it and it is dry inside. did a mini service of boiler but no obvious problems. please help!!!! its spring/summer here so we knw its not frozen pipes. thanks