boiler blown fuses what's cause likely to be ???

[bodgit and scarper]

doing a painting job, closed the valves and took off 1 rad, one of the valves was dripping very slightly. probably lost less than a pint when the fuse blew
the system is header type.. no fill valve under the boiler, or pressure guage on the front..an ideal classic lxff
any way it blew the 3amp fuse by the controller, me like an eejit popped in the nearest fuse to hand, not having spotted the colour of the original and blew bu@@ery out of the controller..
however, on bypassing the controller the hot water sparks up fine but there is no action at all out of the heating when that's hooked up...
so gents what would cause the 3amp fuse to blow in the first place,
was it my fault or just coincidence,
is it something i can get in and sort.. as a moderately competent bod on electrics and plumbing

 

[Slugbabydotcom]

Fuses only blow when they pass to much current.
What causes too much current to pass is not enough resistance between live and neutral. ie. a direct short circuit. Probs caused by letting that iron rich radiator water on to the electrics

 

[ChrisR]

Check the pump. Could have run hot due to needing a pint - don't we all, or it could be coincidence. You can usually find "shorts" or blown up shorts, by smelling for burning.

And no I don't mean where someone's been igniting their farts. Not those shorts...

Sniff the controller too - no not the fat controller .... oh dear ....