How can I fix my Apollo 15/30B wall mounted gas boiler?

APOLLO 15/30B WALL MOUNTED GAS BOILER -I have recently had a new consumer unit fitted My honeywell programmer had not been working correctly as it no longer allowed the heating/water to come on automatically. The heating has not been put on since the beginning of May. The water was heating up ok by manual operation following the fitting of the consumer unit but when we tried the heating it worked for about 10 minutes before tripping the whole circuit. The programmer stopped working and was removed in order to get a new one. When the consumer unit was reset the boiler was still coming on and then tripping everything else immediately producing a very loud "bang" from the boiler . I know this is an old boiler but it has worked ok until recently, only the pilot lite has had to be fixed before. Can anyone help please?