Baxi E133 Fault Code: What It Means And How To Fix It

If your Baxi boiler is showing an E133 fault code or E133 error code, it usually means the boiler has failed to ignite, or has lit and then lost the flame. The boiler locks out and will not restart until it has been reset and the cause dealt with.

We’re Hinckley Plumbing & Heating — Gas Safe registered engineers covering Hinckley, Nuneaton, Leicester, Tamworth, Coventry, Rugby, and Loughborough — and this guide explains what the Baxi E133 fault code on a boiler means, the most common causes, what you can safely check yourself, and when to call us.

What Does The Baxi E133 Fault Code Mean?

The Baxi E133 fault code is an ignition failure or flame loss fault. The boiler has attempted its ignition sequence but has not been able to establish or maintain a flame.

Because the boiler cannot confirm safe combustion, it shuts down. You will typically have no heating and no hot water until it is sorted.

What Is The Baxi E133 Error Code On A Boiler?

The Baxi E133 error code on a boiler is another way of saying the boiler tried to light and couldn’t.

In plain English: the boiler called for gas, sparked, and either nothing lit or the flame went out again straight away. Rather than keep trying, it locks out and shows E133.

What Causes The Baxi E133 Fault Code?

The most common causes of the Baxi E133 fault code on a boiler are:

• No gas reaching the boiler
• A gas meter or emergency control valve turned off
• A prepayment meter with no credit
• A frozen condensate pipe
• Worn or dirty ignition electrodes
• Damaged ignition leads
• A faulty gas valve
• A blocked or restricted flue
• A faulty PCB
• Inadequate gas supply pressure

The first four are worth checking yourself. The rest need a Gas Safe registered engineer.

Is The Baxi E133 Fault Dangerous?

The lockout is a safety feature working correctly — the boiler has stopped rather than continuing to release gas it cannot burn.

If you can smell gas at any point, do not touch the boiler. Turn the gas off at the meter if it is safe to do so, open windows, don’t use light switches, and call the National Gas Emergency Service on 0800 111 999.

How To Fix The Baxi E133 Fault Code

A few safe checks before you call anyone out.

1. Check whether your other gas appliances work. If the hob and gas fire are also dead, the problem is your gas supply rather than the boiler.
2. Check the gas meter is on and, if you’re on a prepayment meter, that it has credit.
3. In cold weather, check the condensate pipe — the white plastic pipe running from the boiler to an outside drain. A gurgling noise from the boiler often points to a blockage here.
4. If it’s frozen, thaw it with warm water poured along its length, or hold a hot water bottle against it. Never use boiling water, as it can crack the pipe.
5. Press the reset button and give the boiler a minute to attempt ignition.

If it fires up and stays running, you’re sorted. If it locks out again, stop.

Don’t reset more than two or three times. Repeated resetting won’t fix a failing component, and it means the boiler is repeatedly attempting to release gas into a system that isn’t lighting it.

Why Does The Baxi E133 Error Code Keep Coming Back?

If E133 clears on a reset but returns, something is preventing reliable ignition each time.

Ignition electrodes are a frequent cause — they wear, carbon up, or drift out of position over years of use, and they’re a routine replacement item. Gas valves fail less often but produce the same symptom. A partially blocked flue or an intermittently freezing condensate pipe can also cause a boiler to lock out only some of the time, which makes it feel random.

When Should You Call Us About A Baxi E133 Boiler Fault?

Call Hinckley Plumbing & Heating if:

• Your other gas appliances work but the boiler still shows E133
• The E133 fault code returns after resetting
• The condensate pipe is clear but the fault persists
• You hear repeated clicking from the boiler with no ignition
• The boiler lights briefly and then cuts out
• The fault appears intermittently over days or weeks

Anything behind the boiler casing — electrodes, gas valve, flue, PCB — is Gas Safe work. It is illegal for anyone not on the Gas Safe Register to carry it out, and that includes removing the front cover.

Book A Baxi Boiler Fault Check

If your Baxi boiler is showing an E133 fault code or E133 error code, we can help.

We cover Hinckley, Nuneaton, Leicester, Tamworth, Coventry, Rugby, and Loughborough, and we’ll give you a clear, honest assessment of whether it’s a supply issue, a worn electrode, or something more involved. Call us or use our contact form to book a boiler inspection.

Baxi E133 Fault Code FAQs

Can I fix the Baxi E133 fault code myself?

Only the basic checks — gas supply, meter credit, and a frozen condensate pipe. Everything else is Gas Safe work.

How many times can I reset a Baxi boiler showing E133?

Two or three at most. If it keeps locking out, it needs diagnosing rather than resetting.

Why does my Baxi boiler show E133 in cold weather?

Most often a frozen condensate pipe. It’s one of the most common causes of ignition lockouts during a cold snap, and it’s usually straightforward to sort.

Will the Baxi E133 error code clear on its own?

Usually no. The boiler stays locked out until reset, and it will only stay running once the underlying cause has been dealt with.