Heavy rain water into combi boiler via the flu?

during last nights storm rain water drained into my combi boiler via its back mounted fan assisted flu. Now the electrics and the gas flow seem fine when operating the boiler but it just wont light. The fan works and the boiler does not cut out but no flame in inspection window. Can I dry this out myself by running the fan or something like that or do i need to call the engineer? Thanks. model is worcester bosch 280