Quick answer: Baxi E133 means the boiler tried to light but couldn’t detect a flame, so it locked out. The most common causes are a break in the gas supply, such as a prepayment meter running out of credit, and, in winter, a frozen condensate pipe. Check your gas and the condensate pipe, then reset once. If E133 comes back, call a Gas Safe engineer.
E133 is one of the most searched Baxi codes in the UK, and it spikes every time the temperature drops below freezing. The reassuring part is that many E133 lockouts are fixable without an engineer. If your Baxi is over 8 years old, out of warranty and E133 keeps returning, that’s a good time to think about a replacement gas boiler in Edinburgh rather than paying for repeat call-outs.
What does the Baxi E133 error code mean?
E133 means the boiler has had an interruption to its gas supply or a flame failure during ignition. Baxi’s own fault table calls it a “gas supply fault”. The boiler tried to fire, didn’t see a flame, and stopped for safety.
On some models the display shows just “133” with a spanner or reset symbol beside it. Some people read it as “E1 33”. They’re all the same fault.
E133 appears on Baxi Duo-tec, Platinum, Assure, EcoBlue and Megaflo boilers, and on the first Baxi 600 and 800 models. Potterton and Main boilers use the same controls, so you’ll see E133 on some of those too. The newest Baxi Combi 2 range uses a different ignition code (E.04.10).
What causes a Baxi E133 fault?
Most E133 faults are caused by the gas supply or a frozen condensate pipe, not by a broken boiler.
| Cause | How common | Can you check it? |
|---|---|---|
| Gas supply interrupted (meter off, no credit, supplier fault) | Very common | Yes |
| Frozen or blocked condensate pipe | Very common in winter | Yes |
| Worn or dirty ignition or flame sensing electrode | Common | No, engineer |
| Faulty gas valve | Less common | No, engineer |
| PCB or wiring fault | Less common | No, engineer |
How do you fix a Baxi E133 error?
Check the gas first, then the condensate pipe, then reset once.
- Try your gas hob or fire. If nothing works, the problem is your gas supply, not the boiler.
- If you have a prepayment or smart pay-as-you-go meter, check the credit. Emergency credit counts too.
- Check the lever on your gas meter is in line with the pipe, which means it’s on.
- In cold weather, look at the white or grey plastic condensate pipe outside. If it’s frozen, thaw it (see below).
- Press the reset button briefly, about 1 second on most current Baxi models. Holding it too long can stop it resetting.
If the gas is fine and E133 returns after one reset, don’t keep trying. Book a boiler repair and an engineer will check the electrodes, gas pressure and gas valve.
If you smell gas, don’t reset the boiler. Turn it off, open windows and call the National Gas Emergency number on 0800 111 999.
Can a frozen condensate pipe cause E133 in Scotland?
Yes. Baxi lists E133 as one of the codes a frozen condensate pipe can trigger, and it’s one of the most common winter causes. When the pipe freezes, waste water backs up inside the boiler and it can’t run.
To thaw it safely:
- Switch the boiler off.
- Find the frozen section. It’s usually the part outside, near the ground or at a bend.
- Pour warm water over it, or hold a hot water bottle against it. Never use boiling water, as it can crack the pipe.
- Once water drains freely, switch the boiler back on and reset it.
Our guide to thawing a frozen condensate pipe has more detail. If yours freezes every winter, an engineer can reroute it or fit a wider, insulated pipe. That’s especially worthwhile in colder spots like the Borders and the Pentland Hills.
How much does it cost to fix Baxi E133?
When the gas supply or a frozen pipe is the cause, E133 costs nothing to fix. When a part has failed, expect roughly these prices.
| Repair | Typical UK cost |
|---|---|
| Topping up meter credit or thawing the condensate pipe | £0 |
| Ignition or flame sensing electrode | £90 to £240 |
| Gas valve replacement | £180 to £380 |
| PCB replacement | £330 to £540 |
Indicative prices from published UK trade guides, 2024 to 2026. Your quote depends on the model and parts needed.
Should you repair or replace a Baxi with E133?
If E133 was a one-off caused by the gas or a frozen pipe, there’s nothing to replace. If an older Baxi keeps locking out and needs a gas valve or circuit board, replacement is usually the better choice.
Boilers over 8 years old are typically out of their manufacturer warranty, so every repair comes out of your pocket. A new A-rated boiler comes with a fresh warranty, often 7 to 10 years, and runs more efficiently than an ageing one. You can get a free new boiler quote in a few minutes and compare the numbers.
Does regular servicing prevent E133?
Yes, servicing heads off most of the boiler-side causes. A boiler service includes cleaning or checking the electrodes, testing gas pressure and checking the condensate trap. We recommend booking yours in autumn, before the first frost.
When should you call an engineer for Baxi E133?
Call a Gas Safe engineer if your gas supply is working, the condensate pipe is clear, and E133 still returns after one reset.
Baxi Boiler Repairs Across Edinburgh and Scotland
The Edinburgh Boiler Company repairs, services and replaces Baxi, Potterton and Main boilers across Edinburgh, the Lothians and the Borders. We carry out boiler repairs in Bathgate and South Queensferry, boiler servicing in Penicuik, and new boiler installations as far south as Peebles, Galashiels and Hawick. If E133 has left you cold, our Gas Safe engineers can help.
Frequently Asked Questions About the Baxi E133 Error
Is E133 the same on Potterton and Main boilers?
Yes. Potterton and Main are part of the same group as Baxi and share many of the same controls, so E133 means a gas supply or ignition fault on those boilers too.
What’s the difference between Baxi E133 and E119?
E133 is a gas or ignition fault. E119 is a low water pressure fault. Topping up the pressure won’t clear E133. Our Baxi E119 guide covers pressure faults.
Why does my Baxi keep showing E133 after a reset?
If E133 keeps returning and your gas supply is fine, a part inside the boiler is likely failing, such as an electrode or the gas valve. That needs an engineer.
Is it safe to keep resetting a Baxi with E133?
No. One reset is fine. Resetting it again and again won’t fix the cause, and it can hide a fault that needs checking. If the first reset doesn’t work, call an engineer. For other Baxi codes, see our Baxi boiler error codes guide.
