Why is the boiler blowing fuses?

Unless a clear obvious component is burnt out and you can see it is faulty, the best way of determining which component is faulty would be to...

  1. Check the electrical polarity of the appliance and fuse rating is correct
  2. Turn off appliance, remove all mains voltage components from the PCB, including any room stats or wiring centres, and link out external controls on the board
  3. Remove transformer if fitted to PCB. May look visually damaged or you can test for ohms or continuity depending on model. Please call our Technical Support helpline on 0330 123 3366 if you do not know what readings you should have.
  4. If the transformer is ok, turn the power back on to see if a fuse blows. If it does, PCB will be faulty, If not, start re-introducing each component one at a time in order of operation e.g. transformer, pump, fan and then external controls to see which one blows fuse.