Boiler
E193
The E193 error code on a Baxi boiler indicates a fault with the fan or air pressure circuit — specifically that the boiler’s PCB (printed circuit board) is not receiving the correct signal from the air pressure switch. This is a lockout fault, meaning your boiler has shut itself down as a safety precaution and will not fire until the issue is resolved.
What does this error mean?
Your Baxi boiler continuously checks that its fan is running at the correct speed and that flue gases can be safely expelled before allowing ignition. The E193 code means the boiler’s control board detected that the air pressure switch — a small safety device that confirms adequate airflow — did not close or open at the expected moment during startup. In plain terms: the boiler isn’t confident that combustion gases can safely exit your home, so it has refused to light.
Est. repair cost
£100–£350 for professional repair depending on faulty component (pressure switch vs. fan vs. PCB)
🔍 Likely causes
🛠️ Step-by-step fix
Perform a boiler reset: Press and hold the reset button (usually marked with a flame and cross symbol) for 3–5 seconds. If the boiler fires up and runs normally, monitor it for 24 hours. If E193 returns, proceed to the next steps.
Check the external flue terminal: Go outside and visually inspect the flue outlet on your external wall or roof. Clear away any visible debris, leaves, or blockages. Do not insert your hands into the flue. If you suspect a bird nest deep inside, stop and call an engineer.
Thaw a frozen condensate pipe (winter months only): Locate the white plastic condensate pipe that exits your boiler and runs to an external drain. If it feels solid or iced over, pour warm (not boiling) water over the external section to thaw it, then reset the boiler. This fix resolves E193 in a significant number of winter callouts.
Check your boiler manual: Confirm that E193 is listed as a fan/air pressure fault in your specific Baxi model’s manual (e.g. Baxi 200, 400, 600, or Duo-tec series). Baxi’s own documentation will confirm whether a reset is the recommended first step for your model.
Do not attempt further DIY: All remaining causes — a faulty pressure switch, failed fan, split sensing tube, or PCB fault — require a Gas Safe registered engineer to diagnose and repair safely. Do not open the boiler casing or attempt to test or replace internal components yourself. This is both dangerous and illegal without Gas Safe registration.
📞 When to call a professional
If the E193 error returns after a reset and the condensate pipe is not frozen, you must call a Gas Safe registered engineer — do not attempt to investigate inside the boiler. Tell them you have a Baxi boiler showing fault code E193, that you’ve already reset it and ruled out a frozen condensate pipe, and ask them to check the fan, air pressure switch, and sensing tubes. Do not continue attempting resets repeatedly, as persistent lockouts can indicate a worsening fault.
⚖️ Repair or replace?
A fan replacement on a Baxi boiler typically costs £200–£350 including parts and labour; an air pressure switch is cheaper at £100–£200 all-in. If your boiler is over 10 years old and requires a fan or PCB replacement, it is worth getting a new boiler quote at the same time — a modern A-rated Baxi or equivalent costs £1,500–£2,500 installed and will be significantly more efficient. For boilers under 8 years old in otherwise good condition, repair is almost always the right call.