Error E05

Safety precautions:

1. If you smell gas, evacuate the property and call the gas emergency number immediately — do not attempt any checks. 2. Before opening the boiler, switch OFF electrical supply at the isolator or fuse, and if you are going to access internal parts also isolate the mains and, where possible, the gas supply. 3. Only proceed if you are competent with basic electrical isolation and safe working practices; otherwise stop and call a Gas Safe engineer. Do not tamper with gas valves, sealed components or attempt combustion tests yourself.

Initial homeowner checks (safe, non-invasive):

1. Reset or power-cycle the boiler: switch off at the mains, wait 30 seconds, switch on and use the boiler reset function. If E05 clears and stays clear, monitor for recurrence. 2. Check external air intake and flue termination for blockages (bird nests, leaves, ice or debris) and remove obvious obstructions. 3. Listen when the boiler tries to fire: do you hear the fan trying to run, a humming, or nothing? Note sounds for the engineer. 4. Check for obvious signs of damage or water ingress around the boiler and wiring; report these to the engineer.

If you are competent and choose to do internal visual inspection (only after isolating electrical power and gas):

1. Remove the outer case following the manual’s instructions only after isolation. 2. Visually inspect the fan and its plug connectors: ensure both connector blocks onto the fan are fully seated, not corroded or burnt, and wiring insulation is intact. 3. Check the fan impeller for free movement by gently turning it by hand; it should rotate freely without rubbing or grinding spots. Look for debris or foreign objects inside the fan housing. 4. Inspect for burnt smells, melted plastic or oil/condensate on the motor — signs of motor failure. 5. If you have multimeter skills and the boiler isolated, you may check the fan motor windings for continuity; do NOT apply mains voltage directly. If comfortable and competent you can also, with the engineer’s guidance, measure whether the fan receives supply voltage when the boiler calls for ignition — but this involves live testing and should be left to a professional.

When to call a professional and what they will do:

1. Call a Gas Safe registered heating engineer if the fault persists after the simple external checks, if connectors/wiring look damaged, if the fan is seized, or if you cannot safely access internal parts. 2. A qualified engineer will safely isolate, remove the boiler cover, check fan supply and signal circuits, test whether the control PCB is commanding the fan, test motor windings, replace the combustion blower if faulty, and check flue safety thermostats/thermal fuses as required. They will also perform a full combustion and safety check after any repair. 3. Do not try to run the boiler if the fan is not operating correctly; operating without a functioning flue fan risks unsafe combustion and carbon monoxide.

Other notes:

1. E05 specifically signals the controller cannot detect fan rotation; related codes (E28, B28/B29 in some manuals) may indicate no signal or incorrect signal from the fan. 2. If the fault is intermittent, record when it happens, any sounds, and whether it follows power interruptions — this information helps the engineer diagnose whether the problem is wiring, the fan, or the control PCB. 3. If you are unsure at any stage, stop and call a Gas Safe engineer. Repairs that involve removing the fan, replacing components or working on gas or wiring must be done by a qualified professional.