BoilerFaultCodesTechnical description
Control fault: Fuse F1 (3.15 AT) defective.
What causes this fault?
This fault occurs when the boiler's internal safety fuse blows to protect the sensitive electronics from an electrical surge or component failure. The most common reason is an internal leak or a failing water pump that has short-circuited and drawn too much power. Because the fuse has blown, the boiler acts as if it has no power at all and will stay completely dark until the fuse and the faulty part are replaced.
This fault is more common at the start of winter when the heating is first turned on, as pumps that have been sitting idle over summer are more likely to seize and cause an electrical short.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.