i disconected pump (pulled out 3 pin connector), put new fuse in and powered up boiler....the boiler appears fine when dormant...lcd reading a temp led lights up.... but as soon as i turn on hot water tap the fuse blows straight away....looks like Mr vaillant going to get a nice fat wad of cash...
whilst having shower a fuse blew on boiler unit. i replaced fuse and switched unit back on, all seemed ok until i turned hot water tap on and fuse blew straight away....any ideas? it is fuse behind timer unit (think fuse has t2e 250v on it but writing very small)...