Not heating

The machine has power (lights work, pump runs) but the boiler isn't heating up — or heats slowly and never reaches operating temperature.

Why it matters — Several possible causes, all worth diagnosing before calling a tech. A blown thermal fuse, a failed heating element, a stuck thermostat, or a failed PID/pstat all produce similar symptoms.

Good to know

• Start with the thermal fuse — it's the most common and easiest fault to fix. Most fuses are accessible after opening the case.
• If the fuse is intact, test the element with a multimeter for continuity. A burnt-out element reads open-circuit.