Boiler Error Code Checker

Name: AR Heating & Gas
Address: 23 Wingate Grange, Houghton le Spring, Tyne and Wear, DH4 6GQ, GB
Telephone: 0191 540 2051
Price range: ££

Pick your brand, enter the code on the display, and we will tell you what it means and what to do next.

1. Select your boiler brand

2. Enter your error code

What boiler error codes actually tell you

When a modern boiler shuts down it almost always puts a code on the display first. That code is the boiler telling you which safety check it failed, which is far more useful than a flashing light. It narrows the problem down before anyone comes out, and it often tells you whether this is something you can sort yourself in five minutes or something that needs a Gas Safe engineer.

Three things are worth knowing before you look yours up.

The same fault has different codes on different brands. An ignition failure is EA on a Worcester Bosch, F28 on a Vaillant, E133 on a Baxi, L2 on an Ideal and E003 on a Navien. Same problem, five different codes, which is why brand matters when you search.

Ignition and pressure faults dominate in winter. A large share of the codes we attend between November and February come back to one of two things: a frozen condensate pipe stopping the boiler from firing, or system pressure that has dropped too low. Both are worth checking before you book anyone.

Do not keep resetting. One reset is reasonable. Repeatedly resetting a boiler that keeps locking out will not fix the fault and can turn a small problem into an expensive one, particularly on flame detection and overheat codes.

Common boiler fault codes by brand

The checker above covers more codes than these, but here are the ones we are called out to most often.

Worcester Bosch

EA — ignition failure, the most common Worcester fault. Often a frozen condensate pipe in winter. Full guide to the EA code.
E9 — the safety limiter has tripped because the boiler overheated. Usually restricted circulation from sludge or a failing pump.
D5 and CE — low water pressure. Repressurise to between 1.0 and 1.5 bar.
C6 — fan fault. Needs an engineer.
A1 — flue problem. Check the external terminal is not blocked.

Vaillant

F28 — ignition failure. Check the gas is on and thaw any external condensate pipe. Full guide to the F28 code.
F22 — low water pressure, the most common Vaillant code of all.
F29 — the flame lit and then went out. Do not keep resetting this one.
F75 — pump or pressure sensor fault, often sludge related.
F20 — overheat protection has shut the boiler down.

Baxi

E133 — ignition failure, the most common Baxi fault. Full guide to the E133 code.
E119 — low water pressure.
E125 — circulation fault, water is not moving properly through the system.
E110 — overheat.

Ideal

L2 — ignition lockout.
F1 — low water pressure.
F2 — flame failure.
FD — fan fault.

Navien

E003 — ignition failure after three attempts.
E016 — overheat.
E012 — flame lost during operation.

Not sure what your code means, or it is not listed? Use the checker at the top of the page, or read our general guide to boiler error codes.

Two things worth checking before you call anyone

The condensate pipe. Condensing boilers drain waste water through a plastic pipe, and where it runs outside a hard frost can freeze it solid. The boiler detects the blockage and shuts down on purpose. It is one of the very few boiler faults you can safely fix yourself with warm water. See how to thaw a frozen condensate pipe.

The pressure gauge. Most combis want 1.0 to 1.5 bar when cold. Sitting in the red and the boiler will refuse to fire. Topping up takes two minutes with the filling loop, but if it drops again within days you have a leak rather than a one off. See boiler pressure that keeps dropping.

If neither applies, or the code points at the fan, the PCB, a thermistor or overheat protection, it needs a Gas Safe engineer. We cover boiler repairs across Sunderland, Newcastle, Durham, Washington, Houghton le Spring and the wider Tyne and Wear area, with fixed price diagnosis and common parts carried on the van.

If it is out of hours and you have no heat at all, see emergency boiler repair. And if this is the second or third lockout this winter, our repair or replace guide is worth five minutes before you spend money on another repair.

Boiler error code FAQs

The questions we get asked most when someone rings with a code on the display.

Can I reset my boiler when it shows an error code? +

One reset is reasonable and will clear a genuine one off. What you should not do is keep resetting a boiler that locks out again straight away. On flame detection and overheat codes in particular, repeated resets can turn a contained fault into a much more expensive one. If it locks out twice, stop and call an engineer.

Why do different boilers use different codes for the same fault? +

Because there is no industry standard. Each manufacturer designs its own diagnostic scheme. An ignition failure is EA on a Worcester Bosch, F28 on a Vaillant, E133 on a Baxi, L2 on an Ideal and E003 on a Navien. That is the same underlying problem with five different labels, which is why you need to select the brand before looking a code up.

What is the most common boiler error code in winter? +

Ignition failure, and the usual cause is a frozen condensate pipe rather than anything wrong with the boiler itself. The waste water pipe freezes, the boiler detects the blockage and shuts down to protect itself. Thawing it with warm, not boiling, water often has the boiler running again within the hour.

Does an error code always mean an expensive repair? +

No. Low pressure codes are usually a two minute job with the filling loop. Frozen condensate is free to fix. Fan, PCB, thermistor and overheat codes are the ones that need an engineer and cost money. The checker tells you which category yours falls into.

My code is not in your list. What now? +

The checker covers the codes we are called to most, not every code every manufacturer has ever used. If yours is not there, ring us on 0191 540 2051 with the make, model and code and we will tell you what it means. Our engineers deal with fault codes every day.

How much does a boiler repair cost? +

Fault diagnosis starts from £89 and you get a fixed price for the repair before any work begins. If the boiler is not worth repairing we will tell you that instead of taking the money.

Code you cannot clear? We will sort it.

Fixed price fault diagnosis from a local Gas Safe engineer, often same day, with common parts carried on the van. No call centre and no hidden charges.

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