Baxi E133 Fault
What the E133 code on a Baxi boiler means — a gas, ignition or flue lockout — the common causes, what you can safely check, and when to call a Gas Safe engineer. Call 07927 882561.
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Upfront cost — no obligation E133 is one of the most common Baxi fault codes, and it means the boiler has failed to light and locked out. Baxi groups three things under E133 — a gas-supply problem, an ignition failure, or a frozen condensate pipe — so the trick is working out which. Some causes are simple and safe to check yourself; the rest need a Gas Safe engineer. Gas First are Gas Safe registered (587401) Baxi engineers across East London — here’s what E133 means and what to do.
What the E133 code means
E133 is a “failed to light” lockout: the Baxi ran its ignition sequence, didn’t establish a flame, and shut down to keep you safe. Baxi uses the same code for three underlying issues — no gas getting to the boiler, an ignition fault, or a frozen condensate pipe backing up in cold weather — which is why the code alone doesn’t tell you the exact repair. It is a lockout, not something to force through by holding reset: if the boiler can’t light, resetting just repeats the same failed attempt. For the full list of codes across brands, see our boiler fault codes guide. (Note: low pressure on a Baxi shows a different code, E119 — a DIY re-pressurise, see low boiler pressure.)
E133 is a “failed to light” lockout: the Baxi ran its ignition sequence, didn’t establish a flame, and shut down to keep you safe.
Common causes of E133
In cold weather, E133 is very often a frozen condensate pipe — the external pipe freezes and backs up, stopping the boiler firing. The other two causes are a gas-supply problem (a gas meter that’s off, an empty prepayment meter, or a wider supply issue — check whether your other gas appliances work) or a fault on the ignition side, such as the ignition electrode or the gas valve. The gas-valve and ignition faults need a Gas Safe engineer to test and confirm.
In cold weather, E133 is very often a frozen condensate pipe — the external pipe freezes and backs up, stopping the boiler firing.
What you can safely check yourself
Two checks are safe. First, make sure the gas is on — if your gas hob or another gas appliance also won’t work, it’s a supply issue rather than the boiler (check the meter and, on a prepayment meter, the credit). Second, in cold weather, check whether the external condensate pipe has frozen and thaw it gently with warm (not boiling) water. Then reset the boiler once, following the manual. If E133 comes straight back, stop resetting and call an engineer — repeatedly resetting a boiler that can’t light won’t fix the cause and isn’t advisable.
Two checks are safe. First, make sure the gas is on — if your gas hob or another gas appliance also won’t work, it’s a supply issue rather…
When to call us — and how we fix it
If the gas supply is fine and nothing is frozen, E133 needs a Gas Safe engineer. We check the gas supply and pressure, test the ignition electrode and gas valve, and inspect the burner, then repair the actual cause so the boiler lights reliably again — with a clear price agreed before any work. We fix E133 and every other Baxi lockout as Baxi engineers across East London, from our Bow and Dagenham bases.
If the gas supply is fine and nothing is frozen, E133 needs a Gas Safe engineer.
Frequently Asked Questions
What does E133 mean on a Baxi boiler?
It's a "failed to light" lockout covering three causes — a gas-supply problem, an ignition failure, or a frozen condensate pipe. The boiler shut down safely because it couldn't establish a flame.
Can I fix a Baxi E133 myself?
Sometimes. Check your gas is on (do other appliances work?) and, in winter, thaw a frozen condensate pipe. Reset once — if E133 returns, call a Gas Safe engineer.
Why does E133 happen in cold weather?
Most often a frozen condensate pipe. The external pipe freezes and backs up, stopping the boiler firing. Thawing it and resetting usually clears it.
E133 keeps coming back after a reset — why?
The boiler still can't light. Repeatedly resetting won't fix a gas or ignition fault — it needs diagnosing by an engineer.
Is E133 the same as low pressure?
No — low pressure on a Baxi shows E119. E133 is a gas, ignition or condensate lockout.
Are you Gas Safe registered?
Yes — registration 587401, and we repair Baxi boilers across East London.
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