If your boiler's ever flashed up a code you don't recognise, you're not alone, it's the question we get asked most on call-outs. Every time a boiler fires up, it checks a few things in order: is there enough pressure, does the pump move the water, does it light, and does the flame stay lit. If any step fails, the boiler stops itself rather than carrying on regardless. The code just tells you which step failed.

Low pressure is the easy one. If your gauge is under about 1 bar, top it up through the filling loop to around 1 to 1.5. But if you're doing that every couple of weeks, that's not pressure anymore, that's a leak, or a failing expansion vessel.

Ignition failure, flame loss, and overheating are different. One reset is fine to try. If it locks out again straight away, stop resetting it, that's a sign something actually needs fixing, not another reset.

Worcester Bosch shows codes like EA 227 or E9. Vaillant uses F.22, F.28, F.29. Baxi shows E119 and E133. Ideal uses F1, F2, L2 and L5. Different brands, same logic underneath.

Here's the part that matters most: the same code can mean completely different things in two different homes. It tells you where the fault happened, not why. That's why a code that clears once and never returns is fine, but one that keeps coming back needs an actual engineer, not more resets.

And if you ever smell gas alongside any of this, skip the code entirely, gas off at the meter, get out, and treat it as an emergency.

If your boiler's playing up in Hackney, Stoke Newington, Clapton, Walthamstow or Islington, we're Gas Safe registered and offer same-day appointments. Call us now on 07877767776, or book online at boilerserviceslondon.co.uk.