POTTERTON PUMA LEAKING, TRIPS MAIN FUSE BOX?

Hi,

Please can somebody answer the following question. My boiler (Potteton Puma 100) is leaking from underneath. I think this is the cause of my mains fuse box tripping. Can somebody tell me what is or maybe the cause of the boiler leaking. The pressue bar is ok. When the mains fuse box trips the boiler socket will not turn on until about an hour. I think this because the water where it is leaking from drys up and doesnt cause a short circuit.