Overview
E161 (sometimes shown as E160/E161) on Baxi Duo-tec / Megaflo boilers means the boiler’s fan or the fan wiring/connection has been detected as faulty. The fan is a critical part that clears combustion gases from the boiler and ensures correct air flow for safe ignition and operation. When the control board detects the fan is not running, running too slowly, or the expected electrical signals are incorrect, the boiler will lock out to protect itself and your home. Severity is moderate to high in the sense that the boiler will usually shut down and you will lose heating and hot water until the fault is fixed. It is not normally an immediate gas-leak emergency, but because the fan is part of the safe flue/combustion system you should not try to override the fault or keep using the boiler. Initial checks and simple actions (reset, clear vents) can be done by a homeowner, but fan replacement, electrical tests and any internal work must be carried out by a Gas Safe registered engineer. Attempting internal repairs yourself can be dangerous and may invalidate warranties or insurance.
Possible Cause: Fan error
Troubleshooting Steps
Safety first
- If you smell gas: do not touch the boiler. Turn off the gas supply at the meter, ventilate the area, leave the property and call the gas emergency number and a Gas Safe engineer immediately. Do not attempt repairs.
- If you are not confident working near gas or mains electricity, stop and call a Gas Safe engineer. Internal checks and replacements must be carried out by a qualified engineer.
Initial homeowner checks (safe, simple steps)
1. Note the exact error code and any display messages. Try a full reset using the boiler reset button (hold for about 3–5 seconds). If the code clears but returns, further action is needed.
2. Check electricity: ensure the boiler is powered (fuse, isolator switch, consumer unit) and the display is on. If the boiler has lost power intermittently, call an engineer.
3. Check the external flue/vent: make sure the flue terminal and surrounding area are clear of debris, bird nests, snow or ice that could restrict airflow. A blocked flue can cause fan and pressure faults.
4. Check system pressure and condensate pipe (if applicable): very low pressure or a frozen/blocked condensate can cause faults; top up system pressure only if you know how and it is safe to do so, following the boiler manual.
5. Try one more reset after these checks. If boiler still locks out with E161 or E160, do not continue resetting repeatedly.
What a qualified engineer will check and do (diagnostic steps they follow)
1. Visual inspection: with power isolated, the engineer will remove the boiler cover and inspect the fan, fan connector and wiring for loose connections, damaged wires, corrosion or burn marks. The common fault can be a faulty fan plug/connector or damaged wiring.
2. Electrical checks: the engineer will measure voltages and signals to the fan and check control board outputs. They will also check relevant connectors indicated in Baxi documentation (fan and PCB connectors). These tests determine whether the fault is the fan motor, the connector/wiring, or the PCB.
3. Mechanical check: the engineer will check the fan for mechanical seizure or sticking and replace the fan if it is worn or seized. They may also run the calibration/commissioning routine after a fan replacement as specified by the manufacturer.
4. Flue/pressure components: if voltages and fan motor are OK, they will check the flue pressure switch and related sensors for faults or blockage that could produce similar symptoms.
5. PCB assessment: if fan and wiring are good, the PCB (control board) may be at fault and will be tested and replaced only if necessary.
Notes and final notes
- Do not attempt to bypass safety interlocks or run the boiler with an unresolved fan fault. That defeats essential safety controls and could create a hazardous situation. Repeatedly resetting the boiler is not recommended.
- If simple homeowner checks (reset, clear outside flue, confirm power and gas supply) do not clear the fault, contact a Gas Safe registered engineer. Tell them the boiler model and that you have E161 (fan) so they arrive prepared with likely parts (fan/connector) and tools.
- If you smell gas, have repeated lockouts, or the boiler behaves unusually (noisy, rough starting), stop use and call a Gas Safe engineer immediately.
Helpful Resources
Boiler Manual
Download the official PDF manual for the Baxi Duo-tec/Megaflo.