Boiler
E168
The E168 error code on a Baxi boiler indicates a fan or air pressure fault — the boiler has detected that the flue fan is not operating correctly and has locked out as a safety precaution. It requires prompt attention, as the boiler will not fire until the fault is resolved.
What does this error mean?
Your Baxi boiler uses a fan to push combustion gases safely out through the flue. The E168 code means the boiler’s control board has detected that the fan speed is incorrect, the fan has failed to start, or the air pressure switch — which confirms the fan is working — has not triggered as expected. Because running without a working fan could allow dangerous gases to build up, the boiler shuts down and locks out automatically.
Est. repair cost
£80–£180 for pressure switch/hose; £150–£350 for fan replacement (parts + Gas Safe labour)
🔍 Likely causes
🛠️ Step-by-step fix
Reset the boiler: Press and hold the reset button (usually marked with a flame or ‘R’) for 3–5 seconds, then wait 2 minutes for it to attempt restart. This clears a temporary lockout and is the only safe first step for a homeowner.
Check the external flue terminal: Go outside and visually inspect the flue outlet (usually on an external wall or roof). Make sure it is not blocked by debris, a bird nest, or ice. Do not poke anything inside the flue pipe.
Check your boiler manual: Confirm that E168 is listed as a fan or air pressure fault in your specific Baxi model’s manual (codes can vary slightly between the Baxi 800, Duo-tec, and Platinum ranges). Download it free from Baxi’s website if needed.
If the error returns after reset or the boiler won’t start at all: Do not attempt further DIY. The fan, pressure switch, hose, or wiring all sit inside the boiler casing — accessing them constitutes gas appliance work and must be carried out by a Gas Safe registered engineer.
Call a Gas Safe engineer and describe the fault: Tell them you have a Baxi [model name] showing E168, that you’ve attempted a reset, and whether the fan is audibly running or completely silent when the boiler tries to fire. This helps them diagnose before arrival.
📞 When to call a professional
Call a Gas Safe registered engineer if the E168 fault returns after a reset, or if the boiler will not attempt to start at all. This is not a DIY repair — the fan, air pressure switch, and associated wiring are internal gas appliance components, and working on them without Gas Safe registration is illegal and dangerous. Tell the engineer it’s an E168 fan or air pressure fault, your boiler model, and whether the fan can be heard spinning on startup.
⚖️ Repair or replace?
Fan replacements on Baxi boilers typically cost £150–£350 all-in (parts and labour), while an air pressure switch or hose is usually £80–£180. If your boiler is over 10–12 years old and requiring repeated repairs, replacement becomes cost-effective — a new Baxi or equivalent A-rated combi boiler costs £1,800–£3,000 fully installed in the UK. For a boiler under 8 years old with no history of faults, repair is almost always the right call.